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LIBRARY OF THE UNIVERSITY OF CALIFORNIA.<br />
GIPT<br />
MISS ROSE WHITING.<br />
Deceived September, i8g6.<br />
Accession No.#J} y*J0 3-<br />
Class No.
A POPULAK<br />
TREATISE 0^ GEMS
A POPULAR<br />
TREATISE ON GEMS,<br />
IN REFERENCE TO THEIR<br />
SCIENTIFIC VALUE:<br />
A GUIDE FOR THE TEACHER OF NATURAL SCIENCES<br />
THE<br />
LAPIDARY, JEWELLER, AND AMATEUR:<br />
TOGETHER WITH A<br />
DESCRIPTION OF THE ELEMENTS OF MINERALOGY, AND ALI<br />
ORNAMENTAL AND ARCHITECTURAL MATERIALS.<br />
BY<br />
DK. L. FEUCHTWANGEK,<br />
H<br />
AND MINERALOGIST, MEMBER OF THE NEW YORK LYCEUM 0V<br />
AT. HIST., AMERICAN ASSOO. OF SCIENCE, OF THE<br />
MINEBALOGICAL SOCIETIES OF JENA,<br />
ALTBNBURG, ETC.<br />
THIRD EDITION.<br />
NEW YOEK:<br />
PUBLISHED BY THE AUTHOR, No. 55 CEDAB ST.<br />
1867.
Entered according to Act of Congress, in the year 1S69.<br />
BY DK. L. FEUCIITW^NGEE,<br />
In th* Clerk's Office of the District Court of the United States for the Southern<br />
District of New York.<br />
JOHN W. AMEBMAN, PRINTKK,<br />
No. 4T Cedar St., N. Y.
PREFACE<br />
IN none of the numerous works on Mineralogy that have<br />
lately been published, have GEMS been treated in a manner<br />
commensurate with the important rank which they hold in the<br />
mineral kingdom. The author of this treatise published in<br />
1838 a small work on Gems, which was well received by the<br />
scientific world. As that edition was soon disposed of, the<br />
author intended to issue a larger and improved edition, but<br />
close application to his legitimate pursuits prevented him from<br />
accomplishing that object. In 1851 he visited the London<br />
Exhibition, where the treasures of the mineral kingdom, and the<br />
profusion of brilliant and costly gems from all quarters of the<br />
globe, formed a collection such as had never before been wit-<br />
nessed ; and he then resolved to embody the facts which he<br />
had there collected in a ne\v work on Gems, which he has been<br />
encouraged to publish by the solicitations of numerous teachers<br />
and jewellers, who had used his former treatise as a work of<br />
reference, and who wish to have a work that will impart useful<br />
and correct information in regard to tjie locality and value of<br />
Gems in the present state of scientific knowledge. As a work<br />
on Gems would be incomplete without a treatise on Mineralogy,<br />
and as the author did not wish to enter into details foreign to<br />
his subject, he was at a loss how to commence ;<br />
but on consult-<br />
ing the recent works on the Elements of Mineralogy of Pro<br />
Nichols and Zimmerman, he was conviiu:<
PREFACE.<br />
of the leading principles of Mineralogy was indispensable, as ar<br />
introduction to his main design ;<br />
and that Crystallography, the<br />
mother of Gems, should be explained, before treating them when<br />
prepared for the dealer or wearer : he concluded, therefore, to<br />
commence his treatise by following the Terminology of Nichols'<br />
Elements of Mineralogy, of which he copied the greater part,<br />
along with some remarks of Dufresnoy, from the study of whose<br />
great work on Mineralogy he derived much valuable informa-<br />
tion. He feels it incumbent on him publicly to acknowledge<br />
his obligations to the author of the Elements of Mineralogy,<br />
for the concise and lucid descriptions contained in the first<br />
part of that work, which should be read by every student of<br />
Mineralogy. In the second part of this work, which treats of<br />
Gems, the author has followed his own system in their classifi-<br />
cation j that is, he has arranged them according to their in-<br />
trinsic value, and not alphabetically, as has been done by some<br />
authors, nor as oxydized stones a system adopted by others.<br />
The diamond is placed at the head of the whole class of Gems,<br />
and the others follow in the order of their commercial value.<br />
Some minerals which are not properly Gems have been in-<br />
cluded in the list, either on account of certain specific characters<br />
which they possess, or their applicability to some useful purpose.<br />
Many mineral substances which belong properly to the geolog-<br />
ical or economical department of the science of mineralogy,<br />
have been treated in this part of the work ; but they occupy<br />
so important a position in the economy of life, that their intro-<br />
duction cannot be regarded as an intrusion. Reference is here<br />
made to the detailed account of coal, marble, granite, and<br />
sienite are they not as valuable as the Gems described in this<br />
treatise ? are they not the foundation on which is to be reared<br />
the opulence of future generations? have they not already<br />
contributed to the aggrandisement of the United States, the<br />
most enterprising nation on the globe ?<br />
The revenue arising from he annual production of eight
PREFACE. 7<br />
million tons of coal is not inconsiderable. The marble of the<br />
country, which is just beginning to be developed, bids- fair to<br />
compete with that of any other country, .and to revolutionize<br />
the civilized world. The marble from California, that from<br />
the quarry lately discovered in Pennsylvania, the Leocadia<br />
Breccia, the Verde- Antique of Vermont, and the white marble<br />
from Canaan, Conn., which is used in the construction of the<br />
Fifth Avenue Hotel, Madison Square, N. Y.,*are referred to as<br />
illustrations. Are not the sienites and the granites which<br />
have, been quarried for the last fifty years; and which have been<br />
used in the erection of all our public edifices, really<br />
as valuable<br />
as Gems ?<br />
Few persons were aware, until recently, of the existence of<br />
fancy (variegated) marbles in this country ;<br />
and Italy, Greece,<br />
and Ireland furnish the materials for ornamenting fine houses<br />
and cemeteries, because our own resources have been overlooked,<br />
or not developed. What will be the condition of things fifty<br />
years hence, when the fine arts will occupy as prominent a position<br />
in this country as in any other, and when wealth and<br />
taste will compete with the arts and sciences for the ascendency ?<br />
The Almighty has converted the vegetables of the forest into a<br />
mineral substance, the animals of the sea into building-stone,<br />
and endowed man with the faculty of exploring and developing<br />
the hidden treasures of nature, and this faculty will soon render<br />
this country independent of all other nations. The principal<br />
aim .of the author has been to explain not only the useful, but<br />
also the ornamental mineral substances, and such compositions<br />
called mosaics as are prepared from them, and he is indebted<br />
for much valuable information pertaining to this branch of the t<br />
subject to the Jury Report of the London Exhibition.
PEEFACE TO THE THIED EDITION.<br />
THE publication of 1859 having been exhausted for several years,<br />
the numerous applications from booksellers for a supply have induced<br />
the author to issue another edition, and to improve it in adding<br />
an Appendix to the work on such subjects which, in his judgment,<br />
was considered indispensable ; it was to give to his readers<br />
the chronology of mineralogical knowledge, from its first dawn to<br />
the present day, and with much perseverance and labor he accomplished<br />
this task. It was thought advisable and useful to add tables<br />
of the distinguishing characteristics of gems, so as to have at one<br />
glance a condensed survey of the physical and chemical characters<br />
of all the gems, and they were, therefore, copied from Mr. Harry<br />
Emanuel's late work on Diamonds and Precious Stones, as also<br />
many remarks on the value and market prices of gems, etc.<br />
The author was requested to have his likeness placed in front of<br />
the work, and reluctantly complied with it but while ;<br />
doing so, he<br />
is satisfied that his numerous friends on the Pacific will consider it<br />
acceptable. On account of the latter change, the former frontispiece<br />
had neeessarily to be altered, and the best place was Part III., where<br />
the individual gems were treated on page 183, but the Kohinoor<br />
and Zircon crystals were deemed best to be replaced by other gems,<br />
which his friend, Mr. G. CX Newcomb, kindly furnished him for copying<br />
; they are a large Ruby spinelle of 100 carats weight, and a<br />
large Hyacinthe, and a beautiful precious Opal, which were photographed<br />
along with various gems and executed very faithfully.<br />
In the present great Paris Exposition, according to the official<br />
catalogue, a great many valuable gems are mentioned, such as the<br />
Crown Jewels of France those from the ; Queen of Sweden ; also<br />
those of Russia and from the various ;<br />
English, German, Turkish<br />
and French jewellers ; also, a Brazilian Topaz, of 3 Ibs. weight,<br />
7 inches long and 4f inches wide, has recently been deposited.<br />
The extensive display of Corals, one set of which was valued at<br />
$2,300, and many others, but, for want of a detailed description,<br />
could not be enumerated in this Treatise.<br />
The author had latterly occasion to examine at the jewelry store<br />
of Messrs. Bishop & Rein, under the Fifth Avenue Hotel, New-York,<br />
a beautiful white Brilliant, of 14 carats weight, and a great variety<br />
of splendid pink Corals. Also, at Doucet's store, Montreal, from<br />
Thunder Bay, Lake Superior, large masses of Amethysts, weighing<br />
several hundred pounds.<br />
The author takes pleasure in recommending the Heliographic<br />
Engraving Company, under the superintendence of Baron Egloffstein.;<br />
the author's likeness having been executed by them with<br />
much skill.<br />
Praise is also due to Mr. Schnapauff, who much improved the<br />
oojoring of the gems, many of them true to nature.<br />
With these few remarks, the author commits herewith the present<br />
edition to the reader, and trusts it may prove useful and instructive,<br />
which will ever gratify the public servant,<br />
LEWIS FEUCHTWANGER, M. D.<br />
NEW-YORK, June 1, 1867.
INTRODUCTION<br />
CONTENTS.<br />
PAET I.<br />
TERMINOLOGY.<br />
PAG*<br />
13<br />
CHAPTER I. Form of minerals 19<br />
" II. Physical properties of minerals 75<br />
" in. Chemical properties of minerals 102<br />
"<br />
IV. Classification of minerals 129<br />
PAET II.<br />
THE GEMS.<br />
Division of Gems 135<br />
Color, gravity, and hardness 137<br />
Chemical characters 139<br />
Composition<br />
Artificial production of Gems and Minerals 140<br />
Geological characters 145<br />
Geographical distribution 146<br />
Practical division and nomenclature 147<br />
History of Gems 148<br />
Sculpture in Gems 151<br />
On Grinding<br />
153<br />
Forms of the diamond 161<br />
Form of Gems 163<br />
Common lapidary ....... 166<br />
Engraving<br />
Sawing and drilling Gems fc 168<br />
1*<br />
139<br />
166
10 CONTENTS.<br />
Grinding and polishing materials<br />
PAGB<br />
168<br />
Heightening the color of Gems 169<br />
Setting of Gems 171<br />
Cleaning Gems 172<br />
Imitations of Gems 172<br />
Price of, and trade in Gems '. . . . 181<br />
Gems for optical purposes<br />
181<br />
PAET III.<br />
CONSIDERATION OF THE INDIVIDUAL GEMS.<br />
Diamond 183<br />
Corundum 214<br />
Sapphire<br />
214<br />
Common corundum 223<br />
Chrysoberyl, Cymophane 225<br />
Spinelle<br />
Topaz<br />
Euclase<br />
Emerald 235<br />
Beryl, aquamarine<br />
240<br />
Zircon, Hyacinth, Jargon<br />
244<br />
Garnet 247<br />
Essonite, Cinnamon -stone 253<br />
Tourmaline, Kubellite, Siberite 254<br />
Quartz<br />
259<br />
Kock crystal<br />
260<br />
Amethyst<br />
266<br />
Common quartz rose quartz 269<br />
"<br />
"<br />
"<br />
"<br />
Cat's eye<br />
Prase<br />
270<br />
271<br />
" " Avanturine 272<br />
Jasper<br />
273<br />
Hornstone .....' 277<br />
Chalcedony<br />
277<br />
Carnelian 279<br />
Heliotrope, Bloodstone 282<br />
Agate<br />
283<br />
Chrysoprase<br />
292<br />
'<br />
227<br />
229<br />
234
CONTENTS. 11<br />
Chrysolite, Peridot, Olivin<br />
PAGB<br />
294<br />
Isolite 297<br />
Opal<br />
Fire opal<br />
Hydrophane<br />
Semi-opal m 306<br />
Cachelong<br />
307<br />
Jasper opal<br />
308<br />
Obsidian 309<br />
Axinite<br />
%<br />
311<br />
Felspar<br />
312<br />
Adularia 312<br />
Common felspar<br />
315<br />
Labrador 317<br />
Hypersthene<br />
320<br />
Idocrase 321<br />
Hauyne<br />
Lapis lazuli 322<br />
Kyanite, Sappare, Disthene 327<br />
Turquoise<br />
329<br />
Natrolite 332<br />
Fluor spar , 333<br />
Malachite .336<br />
Satin spar<br />
Alabaster 341<br />
Amber , 343<br />
Jet 353<br />
Meerschaum 357<br />
Lava , 360<br />
Jade ; 361<br />
Serpentine -. 362<br />
Marble 364<br />
Stalactite and Stalagmite<br />
380<br />
Egyptian and Italian marbles 382<br />
American marbles 383<br />
Pisolite and Oolite 386<br />
Rock of Gibralter 386<br />
Apatite<br />
Lepidolite<br />
Mica.. . 389<br />
299<br />
304<br />
305<br />
322<br />
340<br />
387<br />
389
12 CONTENTS.<br />
Pyrites ... ..<br />
PA 08<br />
390<br />
Kose manganese<br />
391<br />
Porphyry<br />
391<br />
Sienite 393<br />
Granite 396<br />
Pearls , 400<br />
Corals ......... 419<br />
Shell cameos : 425<br />
Mosaic and Pietra Dura.. . 426
INTRODUCTION.<br />
THE natural productions of our globe may be considered<br />
either in their original or in their changed condition. They<br />
are divided into two general classes which are determined,<br />
either by certain characters that do not require explana-<br />
tion or investigation, or, by the external appearances<br />
which are presented by them in their altered condition,<br />
and by investigating the causes which produced the changes<br />
of form or state.<br />
In the former case, the science is called Natural History;<br />
in the latter, Natural Philosophy.<br />
Natural History, considered in reference to the original<br />
properties of natural productions, must, therefore, be di-<br />
vided into organic and inorganic: to the former belong<br />
Zoology and Botany ;<br />
to the latter, Mineralogy.<br />
Botany and Zoology comprise bodies possessed of vitality,<br />
or beings which, increasing by the absorption of nutritive<br />
substances, mature after a certain period ; their parts are<br />
dependent upon each other, and they cannot be separated<br />
without destroying the integrity of the individual, which,<br />
after a certain period, loses its vitality and ceases to exist ;
14 INTRODUCTION.<br />
or death ensues, decomposition takes place, and the original<br />
being is entirely destroyed.<br />
Mineralogy, on the contrary, comprises<br />
those natural<br />
objects which are not possessed of life, and do not increase<br />
by absorption, but merely by accretion that is, by an ex-<br />
ternal growth or addition without any assimilation ; they<br />
do not mature by age ;<br />
their parts may be separated with-<br />
out destroying their individuality; and their formation<br />
being the result of chemical attraction, they are not liable<br />
to decomposition.<br />
Mineralogy comprises two distinct sciences : Mineralogy<br />
proper, which treats of the simple minerals, either as inde-<br />
pendent bodies, or in relation to the characters which serve<br />
to determine and distinguish them ; and G.eology, which<br />
considers both simple and mixed minerals as they exist in<br />
nature, and in their dependent relations with soils and<br />
rocks. Mineralogy describes the individual qualities of the<br />
several mineral species, Geology treats of them only- as<br />
associated in the structure of the earth.<br />
The characters of minerals are ascertained by their morphological,<br />
physical, and chemical properties. That part of<br />
Mineralogy which treats of the application of minerals to<br />
the different arts, is called Economical Mineralogy ; miner-<br />
als used by lapidaries in making ornaments, are called Gems.<br />
Geometry, Physics (Natural Philosophy), and Chemistry,<br />
form the base for the study of Mineralogy, as without a<br />
knowledge of those sciences, the true characters of a min-<br />
eral cannot be ascertained.<br />
Geology is, according to Lyell's explanation,<br />
the science<br />
which investigates the successive changes that have taken<br />
place in the organic and inorganic kingdoms of nature. It
INTRODUCTION. 15<br />
inquires into the causes of these changes, and the influence<br />
which they have exerted in modifying the surface and ex<br />
temal structure of our planet. By these researches into<br />
the state of the earth and its inhabitants at former periods,<br />
we acquire a more perfect knowledge of its present condi-<br />
tion, and* more comprehensive views concerning the laws<br />
now governing its animate and inanimate productions.<br />
When we study history, we obtain a more profound in-<br />
sight into human nature, by instituting a comparison between<br />
the present and former states of society. We trace<br />
the long series of events which have gradually led to the<br />
actual posture of affairs, and by connecting effects with<br />
their causes, we are enabled to classify and retain in the<br />
memory a multitude of complicated relations, the various<br />
peculiarities of national character, the different degrees of<br />
moral and intellectual refinement, and numerous other cir-<br />
cumstances, which, without historical associations, would<br />
be uninteresting or imperfectly understood. When we<br />
carry back similar relations into the history of nature, we<br />
likewise investigate nature's operations in former epochs.<br />
The form of a coast, the configuration of the interior of<br />
a country, the existence and extent of lakes, valleys, and<br />
mountains, can often be traced to the former prevalence of<br />
earthquakes and volcanoes in regions which have long been<br />
undisturbed. To these remote convulsions the present fer-<br />
tility of some districts, the sterile character of others, the<br />
elevation of land above the sea, the climate, and various<br />
peculiarities, may be distinctly referred. Many distinguishing<br />
features of the surface of the earth may often be as-<br />
cribed to the operation, at a remote era, of slow and tran-<br />
quil causes, to the gradual deposition or sediment in a lake
16 INTRODUCTION.<br />
or in the ocean, or to the prolific<br />
increase of testacea and<br />
corals. "We also find in certain localities subterranean de-<br />
posits of coal, consisting of vegetable matter formerly<br />
drifted into seas and lakes. These seas and lakes have<br />
since been filled up, the lands whereon the forests grevt<br />
have disappeared or changed their form, the rivers and<br />
currents which floated the vegetable masses can no longer<br />
be traced, and the plants belonged to species which for ages<br />
have passed away from the surface of our planet, yet the<br />
commercial prosperity and numerical strength of a nation<br />
may now be mainly dependent on the local distribution of<br />
fuel determined By that ancient state of things. Geology<br />
is intimately connected to almost all physical sciences, as<br />
history is to the moral. An historian should, if possible,<br />
be profoundly acquainted with ethics, politics, jurispru-<br />
dence, the military art, theology, and with all branches of<br />
knowledge, by which an insight into human affairs, or into<br />
the moral and intellectual nature of man, can be obtained.<br />
No less desirable is it for a geologist to be well versed in<br />
chemistry, natural philosophy, mineralogy, zoology, com-<br />
parative anatomy, botany, and every science relating to<br />
organic and inorganic nature. Having such accomplishments,<br />
the historian and geologist would rarely fail to draw<br />
correct and philosophical conclusions from the various<br />
monuments transmitted to them from former occurrences.<br />
They would know to what combination of causes analogous<br />
effects were referable, and would often be enabled to supply<br />
by inference information concerning many events unrecorded<br />
in the defective archives of former ages.<br />
Mineralogy is sometimes understood as comprising the<br />
natural history of every portion of inorganic nature. Here
INTRODUCTION. 17<br />
we consider it as limited to the natural history of simple<br />
minerals, or mineral species. In the strictest sense, a min-<br />
eral species is a natural inorganic body, possessing a defi-<br />
nite chemical composition, and assuming a regular deter-<br />
minate form, or series of forms. Many substances heretofore<br />
regarded as minerals will naturally be excluded such<br />
as all the artificial salts, the inorganic secretions of plants<br />
and apimals, the remains of former living beings now im-<br />
bedded in rocks. Many substances originally organic pro<br />
ducts have by common consent found a place in mineral<br />
systems such as coal, amber, and -mineral resins which<br />
also some amorphous substances,<br />
ought not to be the case ;<br />
with no forms or chemical a*s composition, some kinds of<br />
clay, have also been introduced into works on Mineralogy,<br />
but often improperly, and with no beneficial result. Aggregates<br />
of simple minerals or rocks are likewise excluded from<br />
the science of Mineralogy, though the various associations<br />
of minerals, their modes of occurrence, and their geologi-<br />
cal position, are important points in the history of the dif-<br />
ferent species. One most important object in Mineralogy is<br />
a full description of minerals, their essential properties and<br />
distinctive characters, as will enable the student to distin-<br />
guish the various species, and to. recognize them when they<br />
occur in nature.<br />
The gems, or precious stones, are obtained from miner-<br />
als. It is indispensable, therefore, to be fully acquainted<br />
with all the characters which distinguish them from one<br />
another, which is accomplished by the terminology or no-<br />
menclature of the science of Mineralogy that is, with the<br />
meaning of the terms used in describing the properties of<br />
minerals, and the various modifications they may undergo,
18<br />
and also an account of the properties themselves. The<br />
system of classification is another closely related portion of<br />
Mineralogy. It gives an account of the order in which the<br />
mineral species are arranged. A third and most important<br />
part of Mineralogy is the physiography<br />
of the various<br />
species giving an account of their characteristic marks,<br />
and a description of their appearance or external aspect<br />
and forms, their principal physical and chemical properties,<br />
their mode of occurrence, with their geological and geo-<br />
graphical distribution, and their various uses, whether in<br />
nature or whether in tne arts, or as gems for ornamental<br />
purposes,
PART I.<br />
TERMINOLOGY.<br />
CHAPTER I.<br />
FORM OF MIXERAIS.<br />
THE physical properties of a mineral comprise all those<br />
properties belonging to it as a body existing in space, and<br />
consisting of matter aggregated in a peculiar way. The<br />
more important of these are,<br />
its form as shown in crystal-<br />
lization ; its structure as determining its mode of cleavage<br />
and fracture ; its hardness and tenacity ; its weight or spe-<br />
cific gravity ;<br />
magnetism.<br />
and its relations to light, heat, electricity, and<br />
Crystalline and Amorphous. Mineral substances occur<br />
'in two distinct modes of aggregation. Some consist of<br />
minute particles simply collected together, with no regularity<br />
of structure or constancy of External form, and are<br />
named amorphous. All fluid minerals are in this condition,<br />
together with some solid bodies, which appear to have condensed<br />
either from a gelatinous condition like opal, when<br />
they are named porodine, or from a state of igneoue fluidity<br />
like, obsidian and glass, when they are named hyalite. The<br />
other class have their ultimate atoms evidently arranged<br />
according to definite law, and are named crystallim., when<br />
the regulai ity of structure appears only in the internal *is-
20 A PRACTICAL TREATISE ON GEMS.<br />
position of the parts ; and crystallized, when it also produces<br />
a determinate external form, or a crystal.<br />
CRYSTALS.<br />
Faces, Edges, Angles, Axes of Crystals. The word<br />
crystal in mineralogy designates a solid body exhibiting an<br />
original (not artificial) more or less regular polyhedric form.<br />
It is thus bounded by plane surfaces, named faces, which<br />
intersect in straight lines OY. edges, and these again meet in<br />
. points and form solid angles, bounded by three or more<br />
faces. The space occupied by a crystal is often named a<br />
form of crystallization, which is thus the mathematical<br />
figure regarded as independent of the matter that fills it.<br />
Crystals bounded by equal and similar faces are named<br />
simple forms / while those in which the faces are not equal<br />
and similar are named compound forms, or combinations,<br />
being regarded as produced by the union or combination of<br />
two or more simple forms. The cube or hexahedron (fig.<br />
1), bounded by six equal and similar squares;<br />
the octahe-<br />
dron (fig. 2), by eight equilateral triangles ; and the rhom-<br />
bohedron, by six rhombs, are thus simple forms. An axis<br />
of a crystal is a line -passing through its centre and termi-<br />
nating either in the middle of two faces, or of two edges, or<br />
in two angles ; and axes terminating in similar parts of a<br />
crystal are named similar axes. In describing a crystal, one<br />
of its axes is supposed to be vertical or upright, and is then<br />
named the principal axis, and that axis is chosen which is<br />
the only one of its kind in the figure. A few other techni-<br />
cal terms used in describing crystals will be explained as<br />
they occur. .<br />
Systems of Crystallization. The forms of crystals that<br />
occur in nature seem almost innumerable. On examining<br />
them, however, more attentively, certain relations are dis-<br />
.
FORM OF MINERALS. 21<br />
covered even between highly complex crystals. When the<br />
axes are properly chosen, and placed in a right position, the<br />
various faces are observed to group themselves in a regular<br />
and beautiful manner around these axes, and to be all so<br />
related as to compose connected series produced according<br />
to definite laws. In every mineral species there is a certain<br />
form of crystal from which, as a primary, every other form<br />
of crystal observed in that mineral species may be deduced.<br />
In each species the axes, bearing to each other definite<br />
numerical proportions, intersect at angles which are constant.<br />
So also the faces of the various forms are related to each<br />
other, and to their primary, according to certain definite<br />
laws. When viewed in this manner, amd referred to their<br />
simplest forms, the innumerable variety of crystals occurring<br />
in nature may all be reduced to six distinct groups, or, as<br />
The following<br />
they are named, systems of crystallization.<br />
are the names given to these systems of crystallization in<br />
some of the best authors :<br />
Naumann.<br />
1. Tesseral System.<br />
2. Tetragonal System.<br />
8. Hexagonal System.<br />
4. Rhombic System."<br />
5. Monoclinohedric System.<br />
6. Triclinohedric System.<br />
In the following treatise the terminology of Naumann is<br />
adopted, his method of classifying and describing crystals<br />
appearing the simplest and best adapted to promote the<br />
progress of the student.<br />
Holohedric and Hemihedric. Before describing these<br />
systems, it must be observed that certain crystals appear as<br />
the half of others, and are therefore named hemihedric ;<br />
while the crystals with the full number of faces are named<br />
holohedric. Hemihedric crystals are formed when the alter-
22 A PRACTICAL TREATISE ON GEMS.<br />
nate faces or groups of faces of a holohedric crystal increase<br />
symmetrically, so as to obliterate the other faces. Thus,<br />
if four alternate faces of the octohedron increase so as to<br />
obliterate the other four, a tetrahedron with half the num-<br />
ber of faces is formed.<br />
I. The first, or Tesseral System, named from tessera, a<br />
cube, wliich is one of the most frequent varieties, is charac-<br />
terized by three equal axes intersecting each other at right<br />
angles. Properly speaking, this system has no chief axis,<br />
as any one of them may be so named, arid placed upright<br />
in drawing and describing the crystals. Of these there are<br />
thirteen varieties, which are thus classed and named from<br />
the number of their faces :<br />
1. One Tetrahedron, or form with four faces.<br />
2. One Hexahedron, with six faces.<br />
3. One Octahedron, with eight faces.<br />
4. Four Dodecahedrons, with twelve faces.<br />
5. Five Icosi tetrahedrons, with twenty-four faces.<br />
6.r One Tetracontaoctahedron, with forty-eight faces.<br />
The dodecahedrons are further distinguished, according<br />
to the form of their faces, into rhombic, trigonal, deltoid,<br />
and some of the icositetra-<br />
and pentagonal dodecahedrons ;<br />
hedrons have also received peculiar names.<br />
Fig.1. Fig. 2
FORM OF MINERALS. 23<br />
The following is a description, with figures, of the differ-<br />
ent forms above mentioned, beginning with<br />
The Hololiedric forms.<br />
1. The hexahedron or cube (fig. 1) is bounded by sax<br />
equal squares, has twelve edges, formed by faces meeting<br />
at 90, and eight trigonal angles. The principal axes join<br />
the centre points of any two opposite faces. Examples are<br />
fluor spar, galena, boracite.<br />
2. The octahedron (fig. 2), bounded by eight equilateral<br />
triangles, has twelve equal edges, with planes meeting at<br />
109 28', and six tetragonal angles.<br />
*<br />
The principal axes<br />
join the opposite angles, two and two. Example, alum,<br />
spinel, magnetic iron ore.<br />
3. The rhombic-dodecahedron (fig. 3) is bounded by<br />
twelve equal and similar rhombs (diagonals as 1 andv^2),<br />
Fig.* Fig. 4.<br />
has twenty-four equal edges of 120, and six tetragonal and<br />
eight trigonal angles. The principal axes join two opposite<br />
tetragonal angles. Ex., garnet, boracite.<br />
4. The tetrakishexahedrons (variety of icositetrahedron,<br />
fig. 4) are bounded by twenty-four isosceles triangles, ar-<br />
ranged in six groups of four each. They have twelve longer<br />
edges which correspond to those of the primitive or in-
24 A PRACTICAL TREATISE ON GEMS.<br />
scribed tube, and twenty-four shorter edges placed over<br />
each of its faces. The angles are eight hexagonal and six<br />
tetragonal ;<br />
the latter joined two and two by the three prin-<br />
cipal axes. This form varies in general aspect, approach-<br />
on the other, to the rhom-<br />
ing, on the one hand, to the cube ;<br />
bic-dodecahedron. Ex., fluor spar, gold.<br />
5. The triakisoctahedrons (variety of icositetrahedron,<br />
fig. 5) are bounded by twenty-four isosceles triangles, in<br />
eight groups of three, and, like the previous form, vary in<br />
general aspect from the octahedron on one side, to the<br />
rhombic-dodecahedron on .the other. The edges are twelve<br />
longer, corresponding with those of the' inscribed octahedron,<br />
and twenty-four shorter, three and three over each<br />
of the faces. The angles are eight trigonal and six dite-<br />
tragonal (formed by eight faces) ; the latter angles joined<br />
two and two by the principal axes. Ex., galena, diamond.<br />
Fig. 5. Fig. 6.<br />
6. The icositetrahedrons (most common variety, fig. 6)<br />
with .four .<br />
are bounded by twenty-four deltoids or figures<br />
sides, of which two and two adjacent ones are equal. This<br />
form varies from the octahedron to the cube, sometimes<br />
approaching the former and sometimes the latter in general<br />
jispect. The edges are twenty-four longer and twentyfour<br />
shorter. The angles are six tetragonal joined by the
FORM OF MINERALS. 25<br />
principal axes, eight trigonal, and twelve rhombic, or tetra-<br />
gonal with unequal angles.<br />
7. The hexakisoctahedrons (fig. 7), bounded by forty-<br />
eight scalene triangles, vary much in general aspect, approaching<br />
more or less to all the preceding forms ; but<br />
most frequently they have the face? arranged either in six<br />
groups of eight, or eight of six, or twelve of four faces.<br />
There are twenty-four long edges, often corresponding to<br />
those of the rhombic-dodecahedron ; twenty-four interme-<br />
diate edges lying in pairs over each edge of the inscribed<br />
octahedron ;<br />
and twenty-four short edges in pairs over the<br />
edges of the inscribed cube. There are six ditetragonal<br />
angles joined by the principal axes, eight hexagonal and<br />
twelve rhombic angles. Ex., fluor spar, garnet, diamond.<br />
Fig. 7.<br />
The seven forms of crystals now described are related to<br />
each other in the most intimate manner. This will appear<br />
more distinctly from the following account of the derivation<br />
of the forms, with which is conjoined an explanation of the<br />
crystallographic signs or symbols by which they are designated.<br />
We have adopted these symbols throughout this<br />
work, in the belief that they not only mark the forms in a<br />
greatly abbreviated manner, but also exhibit the relations<br />
of the forms and combinations in a way which words could<br />
hardly accomplish.
26 A PRACTICAL TREATISE OX GEMS.<br />
The derivation of forms is -that process by which, from<br />
one form chosen for the purpose, and considered as the<br />
type the fundamental or primary form all the other<br />
forms of a system may be produced, according to fixed prin-<br />
ciples or general laws. In order to understand this process<br />
or method of derivation, the student should keep in mind<br />
that the position of any plane is fixed when the positions<br />
of any three points in it, not all in one straight line, are<br />
known. To determine the position, therefore, of the face<br />
of a crystal, it is only necessary to know the distance of<br />
three points in it from the centre of the crystal, or the<br />
points in which the face or its supposed extension would intersect<br />
the three axes of the crystal. The portion of the<br />
axes between this point and the centre are named parameters,<br />
and the position of the face is sufficiently known when<br />
the relative length or proportion of these parameters is<br />
ascertained. When the position of one face of a simple<br />
form is thus fixed or described, all the other faces are in<br />
like manner fixed, since they are all equal and similar, and<br />
all intersect the axes in a uniform manner ; and the expression<br />
which marks or describes one face, marks and describes<br />
the whole figure.<br />
The octahedron is generally adopted as the primary or<br />
fundamental form of the tessera! system, and distinguished<br />
by the first letter of the name, O. Its faces cut the half<br />
axes at equal distances from the centre ; so that these semi-<br />
axes, or the parameters of the faces, have to each other the<br />
proportion 1:1:1. In order to derive the other forms<br />
from the octahedron, the following construction is em-<br />
ployed. The numbers refer to the descriptions above.<br />
Suppose a plane so placed in each angle of the octahedron<br />
as to be vertical to the axis passing through that<br />
angle and consequently parallel to the two other axes (or<br />
to cut them at an infinite distance = 00); then the hexa-
FORM OF MINERALS. 27<br />
hedron or cube (l)<br />
is produced, designated by the crystal-<br />
of the<br />
lographic sign oo O oo ; expressing the proportion<br />
parameters of its faces, or oo : oo : 1. If a plane is sup-<br />
posed placed in each edge parallel to one axis, and cut-<br />
ting the two other axes at equal distances, the resulting<br />
figure is the rhombic dodecahedron (3), designated by the<br />
sign oo O, the proportion of the parameters of its faces be-<br />
arises when on<br />
ing oo : 1 : 1. The triakisoctahedron (5)<br />
each edge of the octahedron planes are placed cutting the<br />
axis not belonging to that edge at a distance from the centre<br />
m which is a rational number greater than 1. The<br />
is therefore mil 1, and its<br />
proportion of its : parameters<br />
sign mO ;<br />
the most common varieties being fO, 2O, and<br />
3O. When, on the other hand, from a similar distance m<br />
in each two semiaxes prolonged, a plane is drawn to the<br />
other semiaxis, or to each angle, an ikositetrahedron (6) is<br />
formed the ; parameters of its faces<br />
proportion m : 1 : m, and its sign is<br />
have consequently the<br />
mOm the most common<br />
varieties being 2O2 and 303, the former very frequent<br />
in leucite, analcime, and garnet. When, again, planes are<br />
drawn from each angle, or the end of one semiaxis of the<br />
octahedron, parallel to a second axis, and cutting the third<br />
at a distance rc, greater than 1, then the tetrakishexahedron<br />
(4) is formed, the parameter of its faces oo : 1 : n ; its sign<br />
3>On; and the most common varieties in nature ooOf,<br />
oc O2, and oo O3. Finally, if in each semiaxis of the octahedron<br />
two distances, m and ft, be taken, each greater than<br />
1, and m also greater than n, and planes be drawn from<br />
each angle to these points, so that the two planes lying<br />
over each edge cut the second semiaxis belonging to that<br />
edge, at the smaller distance n, and the third axis at the<br />
greater distance m, then the hexakisoctahedron (7) is produced,<br />
the parameters of which are m : n : 1, its sign mOn,<br />
and the most common varieties 3Of, 4O2, and 5Of .
28 A PRACTICAL TREATISE ON GEMS.<br />
The next class of crystals are the semi-tesseral form,s; and<br />
first, those with oblique faces, often named tetrahedral, from<br />
their relation to the tetrahedron. (1.) This form (fig. 8)<br />
Fig. 8.<br />
Fig. 9.<br />
is bounded by four equilateral triangles, has six equal edges<br />
with faces meeting at 70 32 ', and four trigonal angles.<br />
The principal axes join the middle points of each two op-<br />
posite edges. Ex., gray-copper ore, boracite, and helvine.<br />
(2.) The trigonal dodecahedrons (fig. 9) are bounded by<br />
twelve isosceles triangles, and vary in general form from<br />
the tetrahedron to the hexahedron. There are six longer<br />
edges corresponding to those of the inscribed tetrahedron,<br />
and twelve shorter placed three and three over each of its<br />
faces ; and four hexagonal and four trigonal angles. Ex.,<br />
gray-copper ore, and bismuth-blende. (3.) The deltoiddodecahedrons<br />
(fig. 10) are bounded by twelve deltoids,<br />
and vary in general form from the tetrahedron on the one<br />
hand, to the rhombic-dodecahedron on the other. They<br />
have twelve longer edges lying in pairs over the edges of<br />
the inscribed tetrahedron ;<br />
and twelve shorter edges, three<br />
and three over each of its faces. The angles are six tetra-<br />
gonal (rhombic), four acute trigonal,<br />
and four obtuse tri-<br />
gonal angles. The principal axes join two and two opposite<br />
rhombic angles. Ex., gray-copper ore. (4.) The hex-<br />
akistetrahedrons (fig. 11) are bounded by twenty-four
FORM OF MINERALS. 29<br />
scalene triangles, and most commonly have their faces<br />
grouped in four systems of six each. The edges are twelve<br />
shorter and twelve longer, lying in groups of three over<br />
Fig. 10. Fig. 11.<br />
each face of the inscribed tetrahedron, and twelve interme<br />
diate in pairs over its edges. The angles are six rhombic,<br />
joined in pairs by the principal axes, and four acuter and<br />
four obtuser hexagonal angles. Ex., diamond.<br />
The derivation and signs of these forms are as follows :<br />
The tetrahedron arises when four alternate faces of the<br />
octahedron are enlarged, so as to obliterate the other four,<br />
and its sign is hence . But, as either four faces may be<br />
thus enlarged or obliterated, two tetrahedrons can be formed<br />
similar in all respects except in position, and together mak-<br />
ing up the octahedron. These are distinguished by the<br />
signs + and , added to the above symbol, but only the<br />
latter in general expressed thus . In ah 1<br />
hemihedric<br />
systems two forms similarly related occur, which may thus<br />
be named complementary forms. The trigonal dodecahe-<br />
dron is derived from the icositetrahedron, by the expansion<br />
of the alternate trigonal groups of faces. Its sign is -<br />
,
30 A PRACTICAL TREATISE ON GEMS.<br />
2O2<br />
the most common variety being , found in gray-copper<br />
ore. The deltoid-dodecahedron is in like manner the result<br />
of the increase of the alternate trigonal groups of faces of the<br />
triakisoctahedron, and its sign is . Lastly,<br />
the hexakis-<br />
tetrahedron arises in the development of alternate hexa-<br />
gonal groups of faces in the hexakisoctahedron, and its sign<br />
.<br />
mOn ~'<br />
The parallel-faced semitesseral forms are two. (1.) The<br />
pentagonal dodecahedrons (fig. 12) are bounded by twelve<br />
Fig. 12. Fig. 13.<br />
symmetrical pentagons, and vary in general aspect between<br />
the hexahedron and rhombic-dodecahedron. They<br />
have six regular (and in general longer) edges, lying<br />
over the faces of the inscribed hexahedron, and twenty-<br />
four generally shorter (seldom longer) edges, usually lying<br />
in pairs over its edges. The angles are eight of three equal<br />
angles, and twelve of three unequal angles. Each princi-<br />
pal axis unites two opposite regular edges. This form is<br />
derived from the tetrakishexahedron, and its sign is ,<br />
one of the most common varieties being , found fre-<br />
quently in iron pyrites and cobaltine. (2.) The dyakisdo-
FORM OF MINERALS. 31<br />
decahedron (fig. 13), bounded by twenty-four trapezoids<br />
with two sides equal, has twelve short, twelve long, and<br />
twenty-four intermediate edges. The angles are six equi-<br />
angular rhombic, united in pairs by the principal axes, eight<br />
trigonal, and twenty-four irregular tetragonal angles.<br />
derived from the hexakisoctahedron, and its sign is F '<br />
It is<br />
the brackets being used to distinguish it from the hexakiste-<br />
Fig. 14. Fig. 15.<br />
trahedron, also derived from the same primary form. It<br />
occurs in iron pyrites and cobaltine. There are two other<br />
tetrahedral forms, the pentagonal dodecahedron (fig. 14),<br />
and the pentagonal icositetrahedron (fig. 15), both bounded<br />
by irregular pentagons, but not yet observed in nature.<br />
Combinations. These forms of the tesseral system (and<br />
this is true also of the five other systems of crystallization)<br />
not only occur singly, but often two, three, or more are united<br />
in the same crystal, forming what are named combinations.<br />
In this case it is evident that no one of the individual forms<br />
can be completely developed, because the faces of one form<br />
must partially interfere with the faces of the other forms.<br />
A combination therefore implies that the faces of one form<br />
shall appear symmetrically disposed between the faces of<br />
other forms, and consequently in the room of certain of<br />
their edges and angles.<br />
, J<br />
These edges and angles are thus,
32 A PRACTICAL TREATISE ON GEMS.<br />
as it were, cut off, and new ones produced in their place,<br />
which properly belong neither to the one form nor the other,<br />
but are edges or angles of combination. Usually, one form<br />
predominates more than the others, or has more influence on<br />
the general aspect of the crystal, and hence is distinguished<br />
as the predominant form, the others being named subordi-<br />
nate. The following terms used on this subject require ex-<br />
planation. A combination is developed when all the forms<br />
contributing to its formation are pointed out ; and its sign<br />
consists of the signs of these forms, written in the order oi<br />
their influence on the combination, with a point between.<br />
An angle or edge is said to be replaced when it is cut ofl<br />
by one or more secondary planes ;<br />
by one plane, forming equal angles with the adjacent faces ;<br />
and an edge is bevelled when replaced by two planes, which<br />
are equally inclined to the adjacent faces.<br />
it is truncated when cut<br />
It will be readily seen that such combinations may be<br />
exceedingly numerous, or rather infinite ;<br />
and only a few<br />
of the more common can be noticed, simply as specimens<br />
of the class. Many others more complicated will occur in<br />
the descriptive part of this treatise. Among plenotesseral<br />
combinations, the cube, octahedron, and also the rhombicdodecahedron,<br />
are the predominant forms. In fig. 16 the<br />
Fig. 16. Fig. 17.<br />
cube has its angles replaced by the faces of the octahedron,<br />
and the sign of this combination is ooOoo . O. In fig. 17<br />
this process may be regarded as having proceeded still fur-
FORM OF MINERALS. 33<br />
ther, so that the faces of the octahedron now predominate,<br />
and the sign, of the same two elements but in reverse order,<br />
is O . ooOoo. In fig. 18 the cube has its edgesre placed<br />
Fig. la Fig. 19.<br />
by the faces of the rhombic-dodecahedron, the sign being<br />
oo Goo . ccO; while in fig. 19 there is the same combina-<br />
tion, but with the faces of the cube subordinate, and hence<br />
the symbol is ooO . ooOoo . The former figure, it will be<br />
seen, has more the general aspect of the cube ;<br />
the dodecahedron.<br />
the latter of<br />
In combinations of semitesseral forms with oblique faces,<br />
the tetahedron, the rhombic-dodecahedron, or even the<br />
hexahedron, seldomer a trigonal-dodecahedron, are the more<br />
Fig. 20. Fig. 2L<br />
common predominant forms. In fig.<br />
20 two tetrahedrons<br />
in opposite positions, -^ are combined. In 21 a<br />
fig.<br />
2*
34 A PRACTICAL TREATISE ON GEMS.<br />
very complex combination of seven forms is represented in<br />
a crystal of gray-copper ore, its full sign being<br />
(0 .ooOcc (/) . ^<br />
(o).<br />
the letters in brackets connecting them with the respective<br />
faces of the figure. As examples of combinations of semitesseral<br />
forms with parallel faces, we may take fig. 22, in<br />
Fig. 22. Fig. 23.<br />
which each of the angles of the cube is unsymmetrically<br />
replaced by three faces of the dyakisdodecahedron, and<br />
hence ccOoo . I I ; or fig. 23, in which the pentagonal-<br />
dodecahedron has its trigonal angles replaced by the faces<br />
oo02<br />
of the octahedron, consequently with the sign . O.<br />
Figure 24 represents the same combination<br />
but with greater predomi-<br />
nance of the faces of the octahedron,<br />
the crystal being bounded by eight<br />
equilateral<br />
angles.<br />
and twelve isosceles tri-<br />
II. Tetragonal System. This system<br />
has three axes at right angles,<br />
Fig. 24.<br />
two of them equal and one unequal. The last is the principal<br />
axis, and when it is brought into a vertical position the<br />
crystal is said to be placed upright. Its ends are named
FORM OF MINERALS. 38<br />
poles, and the edges connected with them polar edges. The<br />
two other axes are named subordinate or lateral axes, and<br />
a plane passing through them is named the basis of the<br />
crystal. The two planes that pass through the principal<br />
and one of the lateral axes are named normal chief sections,<br />
and a plane through the chief axis intermediate to them, a<br />
diagonal chief section. The name tetragonal<br />
from the form of the basis, which is usually quadratic.<br />
is derived<br />
There are eight tetragonal forms, of which five are closed,<br />
that is, bounded on ah 1<br />
sides by planes, and of definite<br />
extent, and three open, which in certain directions are not<br />
bounded, and consequently of indefinite extent.<br />
The description of the varieties is as follows, it being<br />
premised that a crystallographic pyramid is equivalent to<br />
two geometrical pyramids joined base to base.<br />
Fig. 25. Fig. 26.<br />
Closed forms. (1.) Tetragonal pyramids (figs. 25, 26) are<br />
inclosed by eight isosceles triangles, with four middle edges<br />
all in one plane, and eight polar edges. There are three<br />
kinds of this form, distinguished by the position of the lat-<br />
eral axes. In the first these axes unite the opposite angles ;<br />
in the second they intersect the middle edges equally;
C A PRACTICAL TREATISE ON GEMS.<br />
and in the third they lie in an intermediate position, or<br />
divide these edges unequally ;<br />
the latter being hemihedral<br />
forms. These pyramids are also distinguished as obtuse<br />
(fig. 25) or acute (fig. 26), according as the vertical angle<br />
is greater or less than in the octahedron, which, though<br />
intermediate, is never a tetragonal form. (2.) Ditetragonal<br />
pyramids (fig. 27) are bounded by sixteen scalene triangles,<br />
Fig. 27. Fig. 28.<br />
whose base lines are all in one plane. This form rarely<br />
occurs except in combinations. (3.) Tetragonal sphenoids<br />
(fig. 28), bounded by four isosceles triangles, are the hemihedral<br />
forms of the first variety of tetragonal pyramids.<br />
(4.) The tetragonal scalenohedron (fig. 29), bounded by<br />
eight scalene triangles, whose bases rise and fall in a zig-zag<br />
line, is the hemihedral form of the ditetragonal pyramid.<br />
The latter two forms are rare.<br />
Open forms. Tetragonal prisms (fig. 30) bounded by<br />
four planes parallel to the principal axis; ditetragonal<br />
prisms by eight similar planes. In these prisms the prin-<br />
or to be<br />
cipal axis is supposed to be prolonged infinitely,<br />
unbounded. Where it is very short and the lateral axes
FORM OF MINERALS. 87<br />
infinite, the basal piriacoid is formed, consisting merely ot<br />
two parallel faces.<br />
The various series of tetragonal crystals are distinguished<br />
from each other only by their relative dimensions. To<br />
Fig. 29. Fig. 80.<br />
determine these, one of the series must be chosen as the<br />
fundamental form, and for this purpose a tetragonal pyramid<br />
of the first variety, designated by P as its sign, is selected.<br />
The angle of one of its edges, especially the middle edge,<br />
found by measurement, determines its angular dimensions ;<br />
while the proportion of the principal axis (a) to the lateral<br />
axes supposed equal to 1, gives its linear dimensions. The<br />
parameters, therefore, of each face of the fundamental form<br />
are 1 : 1 : a.<br />
Now if m be any (rational) number, either less or greater<br />
than 1, and if from any distance ma in the principal axis<br />
planes be drawn to the middle edge of P, then new tetra-<br />
gonal pyramids of the first kind, but more or less acute or<br />
obtuse than P, are formed. The general sign of these<br />
pyramids is mP, and the most common varieties ^P, 2P,<br />
3P ; with the chief axis equal to ^, twice or thrice that of<br />
P. If m becomes infinite, or = o>, then the pyramid passes<br />
into a prism, indefinitely extended along the principal axis,
A PBACTICAL TREATISE ON GEMS.<br />
and with the sign ooP; if m=0, which is the case when<br />
the lateral axes are supposed infinite, then it becomes a<br />
pinacoid, consisting properly of two basal faces, open towards<br />
the lateral axes, and designated by the sign OP. The<br />
ditetragonal pyramids are produced by taking in each lateral<br />
axis distances n greater than 1, and drawing two planes to<br />
these points from each of the intermediate polar edges.<br />
The parameters of these planes are therefore m : I : n, and<br />
the general sign of the form mPn, the most common values<br />
of n being J, 2, 3, and oo. When n = oo, a tetragonal<br />
pyramid of the second kind arises, designated generally by<br />
mP oo, the most common in the mineral kingdom being P oo<br />
and 2P oo. The relation of these to pyramids of the first<br />
Fig. 81.<br />
Fig. 32.<br />
kind is shown in fig. 31, where ABBBX is the first, and<br />
ACCCX the second kind of pyramid. In like manner from<br />
the prism ooP, the ditetragonal prisms ooPn are derived,<br />
arid finally when n = oo, the tetragonal prism of the sec-<br />
ond kind, whose sign is oopoo .<br />
The combinations of the tetragonal system are either<br />
holohedric or hemihedric ; but the latter are rare. Prisms<br />
and pinacoids must always be terminated on the open sides<br />
by other forms. Thus in fig. 32 a square prism of the first<br />
kind is terminated by the primary pyramid, and has its
FORM OF MINERALS. 39<br />
lateral angles again replaced by another more acute pyra-<br />
. 2Poo.<br />
mid of the second kind, so that its P sign is ooP .<br />
In fig. 33 a prism of the second kind is first bounded by<br />
Fig. 33. Fig. 84.<br />
the fundamental pyramid, and then has its edges of combi-<br />
nation replaced by a ditetragonal<br />
pyramid, and its sign is here<br />
ooPoo . P<br />
.<br />
3P3. In fig. 34 the<br />
polar edges of the pyramid are<br />
replaced by another pyramid, its<br />
sign being P. Poo . In fig.<br />
35 a<br />
hemihedric form very characteris-<br />
tic of copper pyrites is represented,<br />
P and P' being the two sphenoids,<br />
Fi s- ;35-<br />
a the basal pinacoid, and 5, c, two ditetragonl pyramids.<br />
III. The Hexagonal System. The essential character of<br />
this system is, that it has four axes, three equal lateral axes<br />
intersecting each other in one plane at 60, and one principal<br />
axis at right angles to them. The extremities of the principal<br />
axis are named poles, and sections through it and one<br />
lateral axis, normal chief sections. The plane through the<br />
lateral axes is the basis, and from its hexagonal form gives<br />
the name to the system. As in the last system, its forms<br />
are either closed or open / and are divided into holohedral,
40 A PRACTICAL TREATISE ON GEMS.<br />
hemihedral, and tetartohedral, the last forms with only a<br />
fourth part of their faces developed. The tetartohedral and<br />
many of the hemihedral forms are of rare occurrence, and<br />
only a few of the more common require to be here described.<br />
The hexagonal pyramids (figs. 36, 37) are bounded by<br />
twelve isosceles triangles, and are of three kinds, according<br />
Fig. 36. Fig. 37.<br />
as the lateral axes fall in the angles, in the middle of the<br />
lateral edges, or in another point of these edges, the latter<br />
being hemihedral forms. They are also classed as acute<br />
or obtuse, but without any very precise limits. The trigonal<br />
pyramid is bounded by six triangles, and may be viewed<br />
as the hemihedral form of the hexagonal. The dihexago-<br />
nal pyramid is bounded by twenty-four scalene triangles,<br />
but has never been observed alone, and rarely even in com-<br />
binations. The more common prisms are the hexagonal of<br />
six sides, and the dihexagonal of twelve sides.<br />
As the fundamental form of this system, a particular pyramid<br />
P is chosen, and its dimensions determined either<br />
from the proportion of the lateral to the principal axis<br />
From this<br />
(1 : a), or from the measurement of its angles.<br />
form (mP) others are derived exactly as in the tetragonal
POKM OF MINERALS. 41<br />
system. Thus dihexagonal pyramids are produced with<br />
the general sign wPn, the chief peculiarity being that,<br />
whereas in the tetragonal system n might have any rational<br />
value from 1 to oo, in the hexagonal system it can only<br />
vary from 1 to 2, in consequence of the geometric charac-<br />
ter of the figure. When n=2 the dihexagonal changes<br />
into an hexagonal pyramid of the second kind, whose sign<br />
is raP2. When m is = oo various prisms arise from similar<br />
changes in the value of n ;<br />
and when w=0, the basal pina-<br />
coid.<br />
Few hexagonal mineral species form perfect holohedric<br />
combinations. Though quartz and apatite appear as such,<br />
Fig. 33. Fig. 39.<br />
yet properly the former is a tetartohedral, the latter a hemihedral<br />
species. In holohedric species the predominant<br />
faces are usually those of the two hexagonal prisms ooP<br />
and oo P2, or of the pinacoid OP; while the pyramids P<br />
and 2P2 are the most common subordinate forms. Figure<br />
38 represents the prism, bounded on the extremities by two<br />
pyramids ; one, P, forming the point, the other 2P2, the<br />
rhombic faces on the angles, or ocP . P . 2P2. In some<br />
crystals the lateral edges of the prism are replaced by the
42 A PRACTICAL TREATISE ON GEMS.<br />
second prism o>P2, producing an equiangular twelve-sided<br />
prism, which always represents the combination ooP. ooP2,<br />
and cannot occur as a simple form. An example of a more<br />
complicated combination is seen in fig. 39, of a crystal<br />
of apatite, whose sign with the corresponding letters is<br />
ooP2(e) . OP(P) . $P(r) . P()<br />
. 2P(z) . P2() .<br />
Hexagonal minerals more frequently crystallize in those<br />
series of hemihedral forms that are named rhombohedral,<br />
from the prevalence in them of rhombohedrons. These<br />
are bounded by six rhombs (fig. 40), whose lateral edges do<br />
Fig 40.<br />
not lie in one plane, but vise and fall in a zig-zag manner.<br />
The principal axis unites the two trigonal angles, formed by<br />
three equal plane angles, and in the most common variety<br />
the secondary axes join the middle points of two opposite<br />
edges. When the polar edges form an angle of more than<br />
90, the rhombohedrons are named obtuse ; when of less,<br />
are bounded<br />
acute. Hexagonal scalenohedrons (fig. 41)<br />
do not lie<br />
by twelve scalene triangles, whose lateral edges<br />
in one plane. The principal axis joins the two hexagonal<br />
angles, and the secondary axes the middle points of two<br />
opposite lateral edges.<br />
The rhombohedron is derived from the first kind of<br />
hexagonal pyramid by the hemihedric development<br />
of its<br />
alternate faces. Its general sign should therefore be ;<br />
2
FORM OF MINERALS. 43<br />
but on several grounds it is found better to designate it by<br />
R or raR, and its complimentary figure by niR. When<br />
the prism or pinacoid arise as its limiting forms, they are<br />
designated by ooR and OR, though in no respect changed<br />
from the limiting forms 00 P and OP of the pyramid. The<br />
scalenohedron is properly the hemihedric form of the<br />
but is better derived from the<br />
dihexagonal pyramid,<br />
inscribed rhombohedron mR. If the halves of the prin-<br />
cipal axis of this are multiplied by a definite number n^<br />
Fig. 41.<br />
and then planes drawn from the extremities of this enlarged<br />
axis to the lateral edges of the rhombohedron, as in figure<br />
42, the scalenohedron is constructed. Hence it is designated<br />
by wiR", the n being written on the right hand, like<br />
an algebraic exponent : and the dihexagonal prism is in<br />
like manner designated by ooR".
44 A PRACTICAL TREATISE ON GEMS.<br />
The combinations of rhombohedric forms are very nu-<br />
merous, some hundreds being described in calc-spar alone.<br />
Among the more common is the prism in combination with<br />
a rhombohedron, as in the twin crystal of calc-spar (fig. 43),<br />
Fig. 48. Fig. 44.<br />
with the sign coR. iR, the lower half being<br />
the same<br />
form with the upper, but turned round 180. In figure<br />
44, the rhombohedron mR has its polar edges replaced by<br />
Fig. 45. Fig. 46.<br />
another rhombohedron JwR ; and in figure<br />
45 its lateral<br />
edges bevelled by the scalenohedron mR*. A more com-
FORM OF MINERALS. 45<br />
plex combination of five forms is represented in the crystal<br />
of calc-spar, fig. 46, its sign with the letters on the faces<br />
being R 5<br />
(y) . R<br />
3<br />
(r) . R(P) . 4R(m) . oo R(c). Tetartohedric<br />
combinations are seen most distinctly in pure quartz or rock-<br />
crystal, the pyramids of the first kind appearing as rhom-<br />
bohedrons, those of the second kind as trigonal pyramids,<br />
the dihexahedral prisms as ditrigonal prisms, and the prism<br />
oo P2 as a trigonal prism. Most of these forms, however,<br />
in the combinations<br />
occupy but a very subordinate place<br />
which consist essentially of the prism ooP, and the rhomp<br />
bohedron R .<br />
IV. Rhombic System. The rhombic system is charac-<br />
terized by three axes, all unequal, but at right angles to<br />
each other. One of these is assumed as the chief axis,<br />
when the others are named subordinate. The plane passing<br />
through the secondary axes, or the basis, forms a<br />
rhomb, and from this the name is derived. This system<br />
comprises only a few varieties of forms that are essentially<br />
distinct, and its relations are consequently very simple.<br />
Fig. 47. Fig. 43.<br />
The closed forms are, (1st.) The rhombic pyramids<br />
(figs. 47, 48), bounded by eight scalene triangles, whose
46 A POPULAR TKEATISE ON GEMS.<br />
lateral edges lie in one plane, and form a rhomb. They<br />
have eight polar edges, four acute and four more obtuse.<br />
and four lateral edges, and six rhombic angles, the most<br />
acute at the extremities of the longest axis. (2cl) The<br />
rhombic sphenoids (fig. 49)<br />
are bounded by four scalene<br />
triangles with their lateral<br />
edges not in one plane ;<br />
and are a hemihedric form<br />
of the rhombic pyramid of<br />
unfrequent occurrence. The<br />
open forms again are, (3d.)<br />
Rhombic prisms bounded<br />
by four planes parallel to Fig. 49.<br />
one of the axes which is<br />
indefinitely extended. They are divided into upright and<br />
horizontal prisms, according as either the principal or one of<br />
the lateral axes is supposed to become infinite. For the<br />
latter form the name doma or dome has been used ;<br />
and<br />
two kinds, the macrodome and the brachydome, have been<br />
distinguished. Rhombic pinacoids also arise when one axis<br />
becomes =0, and the two others are indefinitely extended.<br />
In deriving these forms from a primary, a particular<br />
rhombic pyramid P is chosen, and its dimensions determined<br />
either from the angular measurement of two of its edges,<br />
or by the linear proportion of its axes a : b: c\ the greater<br />
lateral axis b being assumed equal to 1. To the greater<br />
lateral axis the name macrodiagonal is frequently given ;<br />
to the shorter, that of brachydiagonal ; and the two principal<br />
sections are in like manner named macrodiagonal and<br />
brachydiagonal, according to the axis they intersect. The<br />
same terms are applied throughout all the derived forms,<br />
where they consequently mark only the position<br />
of the<br />
faces in respect to the axes of the fundamental crystal,
FORM OF MINERALS. 47<br />
without reference to the relative magnitude of the derived<br />
axes.<br />
By multiplying the principal axis by any rational number<br />
m, greater or less than 1, a series of pyramids arise,<br />
whose general sign is mP, and their limits the prism and<br />
pinacoid, the whole series being contained in this formula,<br />
OP rnP P - mP ooP ; which is<br />
the fundamental series, the lateral axes always remaining<br />
From<br />
unchanged.<br />
each member a new<br />
series may, however,<br />
be developed in two<br />
directions by increas-<br />
ing one or other<br />
of the lateral axes.<br />
When the macrodia-<br />
gonal is thus multiplied<br />
by any number<br />
n greater than 1, and<br />
planes drawn from<br />
the distance n to the<br />
polar edges, a new<br />
pyramid is produced,<br />
named a macropyra-<br />
mid, with the sign<br />
wP/i, the mark over<br />
the P pointing out<br />
the axis enlarged.<br />
When M=QO a macrodome<br />
results,with<br />
Fig. 50.<br />
Fig. 51.<br />
the sign mPoo . If the shorter axis is multiplied, then bra-<br />
chypyramids and brachydomes are produced with the signs<br />
?nPn and mPcc . So also from the prism ooP, on the one<br />
side, numerous macroprisms ooP^, with the limiting ma-
48 A POPULAR TREATISE 05* GEMS.<br />
cropinacoid coPoo; on the other, numerous brachyprisma<br />
ooPft,, with the limit form ooPoo, or the brachypinacoid.<br />
In figs. 50, 51, the two domes are shown in their relation<br />
to the primitive pyramid.<br />
The pyramids seldom occur independent, or even as the<br />
predominant forms in a combination, sulphur, however,<br />
being an exception. Prisms or pinacoids usually give the<br />
general character to the crystal, which then appears either<br />
in a columnar or tabular, or even in a rectangular pyramidal<br />
form. The determination of the position of these crystals,<br />
Fig. 52. Fig. 54.<br />
as vertical or horizontal, depends on the choice of the chief<br />
axis of the fundamental form. In the topaz crystal (fig. 52)<br />
the brachyprism and the pyramid are the predominant ele-<br />
ments, associated with the prism, its sign and letters being<br />
53 of stilbite is another ex-<br />
ooP2(Q . P(o) . ooP(m). Fig.<br />
combined with<br />
ample, the macropinacoid co Poo or M, being<br />
the pyramid P(?"), the brachypinacoid ooPoo (T), and the<br />
basal pinacoid OP (P). Another instance is fig. 54 of a<br />
lievrite crystal, where the brachyprism and pyramid com-<br />
bine with the macrodome, P<br />
or coP2 . . Poo . The follow-<br />
ing figures are very common forms of barytes ; figs. 55 and
FORM OF MINERALS. 49<br />
56 being both composed of the pinacoid, a brachydome, and<br />
macrodome, with sign OP<br />
(c).Poo(/)iPoo(d),the<br />
variation in aspect arising<br />
from the predominance of<br />
different faces ;<br />
consisting<br />
and fig. 57<br />
of the macro-<br />
dome -|P oo , the prism<br />
a>P(^), and the pinacoid<br />
OP.<br />
V. The Monodinohe-<br />
dric System. This system<br />
is characterized by three<br />
unequal axes, two of which<br />
intersect each other at an<br />
Fig. 55.<br />
Fig. 53.<br />
oblique angle, and are cut<br />
by the third at right angles.<br />
One of the Fig.<br />
oblique<br />
axes is chosen as the chief axis, and the other axes are then<br />
57.<br />
distinguished as the orthodiagonal (right-angled) and clinodiagonal<br />
(oblique-angled). The same terms are applied to<br />
the chief sections, and the name of the system refers to the<br />
fact that these two planes and the base, together with two<br />
right angles, form also one oblique angle C.<br />
The forms of this system approach very near to those of<br />
the rhombic series, but the inclination of the axes, even<br />
when almost a right angle, gives them a peculiar character,<br />
by which they are always readily distinguished. Each<br />
pyramid thus separates into two altogether independent<br />
forms or hemipyramids. Three varieties of prism also oc-<br />
cur, vertical, inclined, and horizontal, with faces parallel<br />
to the chief axis, the clinodiagonal or the orthodiagonal.<br />
The horizontal prisms, like the pyramids, separate into two<br />
independent partial forms, named hemiprisms or hemi-<br />
3
50 A POPULAR TREATISE ON GEMS.<br />
domes. The inclined prisms are often designated clino-<br />
domes, the term prism being restricted to the vertical<br />
forms. Orthopinacoids and clinopinacoids<br />
are also distinguished<br />
from their position in relation to the axes.<br />
The monoclinohedric pyramids (fig. 58) are bounded by<br />
A eight scalene triangles of two<br />
kinds, four and four only be-<br />
ing similar. Their lateral<br />
&<br />
edges lie all in one plane,<br />
and the similar triangles are<br />
placed in pairs on the clinodiagonal<br />
polar edges. The<br />
two pairs<br />
in the acute angle<br />
between the orthodiagonal<br />
and basal section are desig-<br />
nated the positive hemipyra-<br />
while the two pairs in<br />
mid ;<br />
the obtuse angles of the same<br />
sections form together the negative hemipyramid. But as<br />
these hemipyramids are wholly independent of each other,<br />
they are rarely observed combined. More frequently each<br />
occurs alone, and then forms a prism-like figure, with faces<br />
parallel to the polar edges, and open at the extremities.<br />
Hence, like all prisms, they can only appear in combination<br />
with other forms. The vertical prisms are bounded by<br />
four equal faces parallel to the principal axis, and the cross<br />
section is a rhomb ; the clinodomes have a similar form<br />
and section ; while the horizontal prisms or domes have<br />
unequal faces, and their section is a rhomboid.<br />
The mode of derivation of these forms closely resembles<br />
that of the rhombic series. A complete pyramid is assumed<br />
as the fundamental form, and designated =b P, in<br />
order to express the two portions of which it consists. Its<br />
dimensioRS a.re given when the proportion of its axes $;: c,
FORM OF MINERALS. 51<br />
and the angular inclination of the oblique axes (7, which is<br />
also that of the orthodiagonal section to the basis, are<br />
known.<br />
dbwP<br />
The fundamental series<br />
P mP<br />
of forms is OP<br />
ooP from each of<br />
;<br />
whose members, by changing the dimensions of the other<br />
axes, new forms may be again derived. Thus from mP,<br />
by multiplying the orthodiagonal by any number n, a series<br />
of orthopyramids rtraP/*, is produced with the orthodomes<br />
raPoo , as limiting forms. The clinodiagonal produces a<br />
similar series, distinguished from the former by the sign<br />
being put in brackets, thus, db(wPw), with the limiting<br />
clinodome ( mP ) always completely formed, and therefore<br />
without the signs attached. From o>P arise ortho-<br />
prisms oo Ptt, and the orthopinacoid ooPoo; and clino-<br />
prisms (ooPtt), and the clinopinacoid (ooPoo).<br />
The combinations of this system may be easily under-<br />
stood from their resemblance to those of the rhombic ;<br />
the<br />
chief difficulty being in the occurrence of partial forms,<br />
which, however, closely resemble the hemihedric forms of<br />
the previous systems. We shall therefore only select a few<br />
examples frequently observed in the mineral kingdom.<br />
Fig. 59 represents a very common form of gypsum crystals<br />
Fig. 59. Fig. 60.<br />
(ooPoo) (P) . ooP(/) . P(&).<br />
The most common form of<br />
augite is represented in fig. 60, with the sign ct>P(m) .
52 A POPULAR TREATISE ON GEMS.<br />
oo Poo (r) . ( ooPoo ) (I) . P(s). Fig. 61 is a crystal of com<br />
mon felspar or orthoclase, composed of the clinopinacoid<br />
(ooPoo) (Jf), the prism ooP(f T<br />
), the basal pinacoid OP<br />
(P), and the hemidomes 2P (y) : to which, in fig.<br />
Fig. 61. Fig. 62.<br />
62 of<br />
the same mineral, the hemipyramid P(o), and the clinodome<br />
( 2Poo ) (rc), are added.<br />
VI. Tridinohedric System. This is the least regular of<br />
all the systems, and departs the most widely from symmetry<br />
of form. The axes are all unequal, and inclined at angles<br />
none of which are right angles, so that to determine any<br />
crystal or series of forms the proportion of the axes a : b : c,<br />
and also their angles, or those of the inclination of the chief<br />
sections, must be known. As in the previous system, one<br />
axis is chosen as the principal axis, and the two others dis-<br />
tinguished as the macrodiagonal and brachydiagonal axes.<br />
In consequence of the oblique position of the principal sec-<br />
tions, this system consists entirely of partial forms wholly<br />
independent on each other, and each composed only of two<br />
parallel faces. The complete pyramid is thus broken up<br />
into four distinct quarter pyramids, and the prism into two<br />
hemiprisms. Each of these partial forms is thus nothing<br />
more than a pair of parallel planes, and the various forms<br />
mere individual faces. This circumstance<br />
consequently
FORM OF MINERALS. 53<br />
renders many triclinohedric crystals very unsymmetrical in<br />
appearance.<br />
Triclinohedric pyramids (fig. 63)<br />
are bounded by eight triangles, whose<br />
lateral edges lie in one plane. They<br />
are equal and parallel two and two<br />
to each other ;<br />
each pair forming, as<br />
just stated, a tetartopyramid or open<br />
form, only limited by combination<br />
with other forms, or, as we may suppose,<br />
by the chief sections. The<br />
prisms are again either vertical or in-<br />
the latter named domes, and<br />
clined ;<br />
their section is always rhomboidal. In deriving the forms,<br />
the fundamental pyramid is placed upright with its brachy-<br />
diagonal axis to the spectator, and the .partial forms desig-<br />
nated, the two upper by 'P and P', the two lower by ,P<br />
The further derivation now follows<br />
and P y , as hi the figure.<br />
Fig. 63.<br />
as in the rhombic system, with the modifications already<br />
mentioned, so that we need not delay on it longer, especially<br />
as the minerals crystallizing in these forms are not numerous.<br />
Fig. 64<br />
Some combinations of this system, as the series exhibited<br />
by most of the felspars, approach very near to the mono-<br />
clinohedric system ; while others, as the blue copper, 01
A POPULAR TREATISE ON GEMS.<br />
vitiiol, and axinite, show great incompleteness and want of<br />
symmetry. In the latter case the determination of the<br />
forms is often difficult and requires great attention. As<br />
specimens, we may notice the albite crystal (fig. 64), in<br />
which P is the basal piuacoid OP; J/the brachydiagonal<br />
pinacoid ooPco; s the upper right pyramid P'; Zthe right<br />
hemiprism ooP'; T the left hemiprism oo'P; and x the<br />
hemidome 'P'oo . Figures 65 and 66 are crystals of axinite,<br />
Fig. 65. Fig. 6G.<br />
the former from Dauphine, the latter very common in Corn-<br />
wall, of whose faces the following is the : development r<br />
the macropinacoid ooPoo ; P<br />
the left upper quarter pyramid 'P ;<br />
pyramid 2'P; s the left upper partial<br />
pyramid 3'P3 ;<br />
the left hemiprism co'P; u<br />
and x the hemidome 2'P,oo .<br />
Imperfections of Crystals.<br />
I the left upper quarter<br />
form of the macro-<br />
In the foregoing description of the forms of crystals the<br />
planes have been supposed smooth and even, the faces<br />
equal and uniform, or at the same distance from the centre<br />
or point of intersection of the axes, and each crystal also<br />
perfect or fully formed and complete on every side. In<br />
nature, however, these conditions are rarely if ever realized,<br />
and the edges of crystals are seldom straight lines, or<br />
the faces mathematical plane surfaces. A very interesting<br />
variety of these irregularities, which pervades all the systems<br />
except the tesseral, is named hemimorphism. In this
FORM OP MIXEEALS. 55<br />
the crystals are bounded on the opposite ends of their chiet<br />
axis by faces belonging to distinct forms, and hence only<br />
the upper or under half of each form is produced, or the<br />
crystal, as the name implies, is half-formed. Figure 67 represents<br />
a common variety of tourmaline, bounded on the<br />
Fig. 67. Fig. 63.<br />
upper end by the planes of the rhombohedrons R and 2R,<br />
and on the lower end by the basal piuacoid. In fig. 68 of<br />
electric calamine the upper extremity shows the basis &,<br />
two brachydomes o and p, and two macrodomes m and l\<br />
while on the lower end it is bounded by ;the faces P of the<br />
primary form. This appearance becomes more interesting<br />
from the fact that most hemimorphic crystals acquire polar<br />
electricity from heat, that is, exhibit opposite kinds of<br />
electricity at opposite ends of the crystal.<br />
The faces of crystals are very frequently rendered im-<br />
perfect by striae, or minute linear and parallel elevations<br />
and depressions. These arise in the oscillatory combination<br />
of two crystal forms, alternately prevailing through small<br />
spaces. The striae, therefore, are in reality the edges of<br />
combined forms. They are very common on quartz, shorl,<br />
and some other minerals ; and frequently indicate combina-<br />
tions where only a simple form would otherwise appear to<br />
exist. The cubes and pentagonal dodecahedrons of iron
56 A POPULAR TREATISE ON GEMS.<br />
pyrites are frequently striated, and in three directions at<br />
right angles to each other. In calc-spar the faces of the<br />
rhombohedron, JR (g in fig. 43 above) are almost never<br />
without striae parallel to the oblique diagonal. The stria-<br />
tion is said to be simple when only one series of parallel<br />
lines appears on each face, or feathered when two systems<br />
diverge from a common line. In other crystals the faces,<br />
then said to be drusy, are covered by numerous projecting<br />
angles of smaller crystals; an imperfection often seen in<br />
fluor spar. The faces of crystals occasionally appear curved<br />
either, as in tourmaline and beryl, from the peculiar oscil-<br />
latory combination mentioned, or by the union of several<br />
crystals at obtuse angles, like stones in a vault, as in stilbite<br />
and prehnite. A true curvature of the faces probably oc-<br />
curs in the saddle-shaped rhombohedrons of brown spar<br />
and siderite, in the lens-like crystals of gypsum, and in the<br />
curved faces so common on diamond crystals. In chabasite<br />
similar curved faces occur, but concave. In galena and<br />
augite the crystals are often rounded on the corners, as if by<br />
an incipient state effusion. On other crystals the faces are<br />
rendered uneven from inequalities following no certain rule.<br />
These imperfections furnish valuable assistance in develop-<br />
ing very complex combinations, all the faces of each individual<br />
form being distinguished by the same peculiarity of<br />
surface.<br />
Irregularities in the forms of crystals are produced when<br />
the corresponding faces are placed at unequal distances<br />
from the centre, and consequently differ in form and size.<br />
Thus the cubes and octahedrons of iron pyrites, galena, and<br />
fluor spar, are often lengthened along one axis. Quartz is<br />
subject to many such irregularities, which are seen in a very<br />
remarkable manner on the beautiful transparent and sharply<br />
angular crystals from Dauphine. In such irregular forms,<br />
instead of one line, the axes are then represented by an
FOKM OF MINERALS. 57<br />
infinite number of lines, parallel to the ideal axis of the<br />
figure. The same irregularity carried to a greater extent<br />
frequently causes certain faces required for the symmetry<br />
of the form, altogether to disappear. Again, some crystals<br />
do not fill the space marked out by their outline, holes and<br />
vacancies being left in the faces, occasionally to such an<br />
extent that they seem little more than mere skeletons.<br />
This appearance is very common on crystals produced artificially,<br />
as in common salt, alum, bismuth, silver, &c. A<br />
perfect crystal can only be produced when, during its formation,<br />
it is completely isolated, so as to have full room to<br />
expand on every side. Hence the most perfect crystals<br />
have been originally imbedded singly in some uniform rock<br />
mass. Next to them in perfection are forms that grow<br />
singly, on the surface of some mass of similar or distinct<br />
composition, especially when the point of adherence is<br />
small. An incompleteness of form, or at least a difficulty<br />
in determining it, arises from the minuteness of some crys-<br />
tals, or from their contracted dimensions in certain direc-<br />
tions. Thus some appear mere tabular or lamellar planes,<br />
while others run out into acicular, needle-shaped, or capillary<br />
crystals. Amid all these modifications of the general<br />
form of the crystal, of the condition and aspect of its indi-<br />
vidual faces, or of its linear dimensions, one important ele-<br />
ment, the angular measurement, remains constant. In some<br />
monoaxial crystals, indeed, increase of temperature produces<br />
an unequal expansion in different directions, slightly changing<br />
the relative inclination of the faces, but so small as to<br />
be scarcely perceptible in common measurements, and hence<br />
producing no ambiguity. More important are the angular<br />
changes which in many species accompany slight changes<br />
in chemical composition, particularly<br />
in the relative proportions<br />
of certain isomorphous elements. But notwithstanding<br />
these limitations, the great truth of the permanence of
58 A POPULAR TREATISE ON GEMS.<br />
the angular dimensions of crystals, announced by Rome de<br />
1'Isle, remains unaffected; only, as Mohs well states, it<br />
must not be interpreted with a rigid immutability, incon-<br />
sistent with the whole analogy of other parts of nature.<br />
The Goniometer and Measurement of Crystals.<br />
The fact just stated of the permanence of the angular di-<br />
mensions of crystals, shows the importance of some accurate<br />
method of measuring their angles ; that is, the inclination<br />
of two faces to each other.<br />
Two instruments have been<br />
specially used for this purpose,<br />
the common or contact<br />
goniometer, invented by Ca-<br />
ringeau, and the reflecting goniometer<br />
of Wollaston. The<br />
former is simply two brass<br />
rulers turning on a common<br />
centre, between which the<br />
crystal is so placed<br />
that its<br />
faces coincide with the edges<br />
of the rulers, and the angle is<br />
then measured on a graduated<br />
arc. This instrument is suffi-<br />
ciently accurate for many pur-<br />
poses and for large crystals ;<br />
but for precise determination<br />
is far inferior to the reflecting<br />
goniometer. This requires<br />
smooth and even faces, but<br />
these may be very small, even<br />
Fig. 69.<br />
the hundredth of an inch, in skilful hands ; and as small<br />
crystals are generally most perfect, far greater accuracy can
FORM OF MINERALS. 59<br />
be attained, and the measurement depended on to one<br />
minute (!').<br />
The reflecting goniometer is represented in fig. 69. It<br />
consists essentially of a graduated circle mm, divided on its<br />
edge into twice 180, or more often into half degrees, the<br />
minutes being read off by the vernier hh. This circle turns<br />
this the<br />
on an axis connected with ft, so that by turning<br />
circle is moved round, but is stopped at 1 80, when moving<br />
in one direction, by a spring at k. The other part of the<br />
instrument is intended to attach and adjust the crystal to<br />
be measured. The first axis of mm is hollow, and a second<br />
axis, , passes through it from ss, so that this and all the<br />
connected parts from b tof can be turned without moving<br />
the circle mm. The axis d passes through a hole in be, so<br />
that it can turn the arm de into any required position ; f is<br />
a similar axis turning the arm og and ; pq a fourth axis, in<br />
like manner movable in g, and with a small knob at q, to<br />
which the crystal to be measured is attached.<br />
When about to use the instrument, it should be placed<br />
on a table, with its base horizontal, which is readily done<br />
by the screws in it, and opposite to a window at about 12<br />
or 15 feet distance, so that its axis shall be parallel to the<br />
horizontal bars of the window. One of the upper bars of<br />
the window, and also the lower bar, or, instead of the lat-<br />
ter, a white line on the floor or table parallel to the window,<br />
should then be chosen in order to adjust the crystal. The<br />
observer places himself behind the instrument with the side<br />
a at his right hand. The crystal is then attached to q by<br />
a piece of wax, with the two faces to be measured upward.<br />
The axis fo is made parallel to o#, and the eye being<br />
brought near to the first face of the crystal, the axes aa<br />
and p are turned till the image of the window is seen reflected<br />
in the face with the horizontal and vertical bars in<br />
their position. The axis d is then turned through a con-
60 A POPULAR TREATISE ON GEMS.<br />
siderable angle (say 60), and the image of the window<br />
again sought and brought into its proper place by turning<br />
the axis/", without moving p. When this is done, that face<br />
is brought into its true position, normal to d, so that no<br />
motion of d can disarrange it. Hence the image of the<br />
window may now be sought in the second face and brought<br />
into its true position, with the horizontal bars seen horizon-<br />
tal, by moving the axes d and a. When this is done the<br />
crystal is properly adjusted, and the angle is thus measured.<br />
First bring the zero of the circle and vernier to coincide,<br />
and then turn the inner axis a or as, and move the eye till<br />
the image of the upper bar of the window reflected from<br />
the more distant face of the crystal coincides with the lower<br />
bar or horizontal line seen directly. Keeping the eye in<br />
its place, turn the outer axis tt till the reflected image of<br />
the upper bar in the other face in like manner coincides<br />
with the lower line, and the angle of the two faces is then<br />
read off on the divided circle. As the angle measured is<br />
not directly that of the faces, but of the rays of light re-<br />
flected from them, or the difference of the angle wanted<br />
from 180, the circle has the degrees numbered in the reverse<br />
direction, so as to give the angle without the trouble<br />
of subtracting the one from the other.<br />
The above apparatus for adjusting the crystal is an im-<br />
provement suggested by Naumann. In the original instrument<br />
the axis fo was made to push in or out in a sheath,<br />
and had a small brass plate, bent at right angles, inserted<br />
in a cleft at o, to which the crystal was attached. The crystal<br />
was adjusted, as formerly, by moving the plate, or the<br />
axis/b, and by slight motion of the arm de, which should<br />
be at right angles nearly to be when used. A considerable<br />
improvement is, to have a small mirror fixed on the stand<br />
below the crystal, with its face parallel to the axis aa, and<br />
inclined at 45 to the window, when the lower line can be
FORM OF MINERALS. 61<br />
dispensed with, and the instrument used for various other<br />
purposes of angular measurement. Many alterations have<br />
been suggested for the purpose of insuring greater accuracy,<br />
but the simple instrument is sufficient for all purposes of determinative<br />
mineralogy, and the error from the instrument<br />
will in most cases be less than the actual variations in the<br />
dimensions of the crystals. Greater simplicity is indeed<br />
rather desirable, and the student will often find it sufficient<br />
to attach the crystal by a piece of wax to the axis a directly,<br />
and give it the further adjustment by the hand. The only<br />
use of the parts from b to q is to enable the observer to<br />
place the crystal properly ; that is, with the edge to be<br />
measured parallel to the axis of the instrument, and as<br />
nearly as possible coinciding with its centre. This is<br />
effected when the reflection of the horizontal bar in the<br />
two faces appears parallel to that edge.<br />
Modes or Twin Crystals.<br />
When two similar crystals of a mineral species are united<br />
with their similar faces and axes parallel, the one forms<br />
merely a continuation or enlargement of the other, and<br />
every crystal may be regarded as thus built up of a number<br />
of smaller crystals. Frequently, however, crystals are<br />
united according to precise laws, though all their similar<br />
faces and axes are not parallel, and then are named macles<br />
or twin crystals. In one class of macles the axes of the<br />
two crystals are parallel, and in another they are inclined.<br />
The former only occur among hemihedric forms, and the<br />
two crystals are then combined in the exact position in<br />
which they would be derived from or reproduce the pri-<br />
mary holohedric form. The second class, with oblique<br />
axes, occur both in holohedric and hemihedric forms, and<br />
the two individuals are placed in perfect symmetry to each
62 A POPULAR TREATISE ON GEMS.<br />
other, in reference to a particular face of the crystal which<br />
forms the plane of union, or the equator of the made. We<br />
may also suppose the two crystals originally parallel, and<br />
the one turned round the normal of the united faces by 180<br />
(often 90 or 60), while the other is stationary.<br />
Or we<br />
may suppose a crystal cut into halves in a particular direc-<br />
tion, and one half turned 1 80 on the other ; and hence the<br />
name of hemitrope given to them by Hauy. The position<br />
of the two individuals in this case corresponds with that of<br />
an object and its image in a mirror, whose surface then<br />
represents the plane of union.<br />
The manner in which the crystals unite also differs.<br />
Some are merely opposed or in simple contact ; others are,<br />
as it were, grown together, and mutually interpenetrate,<br />
occasionally so completely as to appear like one individual.<br />
The twin edges and angles in which the two unite are often<br />
when the<br />
re-entering ; or they may coincide in one plane,<br />
line of union is either imperceptible, or is only marked by<br />
the meeting of two systems of striae, or other diversity in<br />
the physical characters of the two faces.<br />
The formation of twin crystals may be again repeated,<br />
forming groups of three, four, or more. When the faces of<br />
union are parallel to each other, the crystals form rows of<br />
indeterminate extent; where they are not parallel, they<br />
may return into each other in circles, or form bouquet-like<br />
or other groups. Where crystals are merely in juxtaposition,<br />
they are sometimes much shortened in the direction<br />
occur in a series with<br />
of the twin axis ; and where many<br />
parallel position, are often compressed into very thin plates,<br />
frequently not thicker than paper, giving to the surface of<br />
the aggregate a peculiar striated aspect.<br />
Only a few twin crystals in the different systems can be<br />
noticed, chiefly as examples of this mode of formation. In<br />
the tesseral system, forms that unite with parallel axes pro-
F011M OF MINERALS. 63<br />
duce intersecting macles like the pentagonal dodecahedrons<br />
of iron pyrites in fig. 70, and the tetrahedrons of gray-cop-<br />
Fig. 70. Fig. 71.<br />
per or fhhlore in fig. 71, a similar formation also occurring '<br />
in the diamond. In macles with inclined axes the two<br />
forms almost always unite by a face of the octahedron, and<br />
the two individuals are then generally apposed and short-<br />
ened in the direction of the twin axis by one half, so that<br />
they appear like a crystal that has been divided by a plane<br />
parallel to one of its faces, and the two halves turned round<br />
on each other by an angle of 180. In this manner two<br />
octahedrons of the spinel, magnetic iron ore, or automolite<br />
Fig. 72. Fig. 73.<br />
(fig. 72), are frequently united. The same law prevails in<br />
the intersecting cubes of fluor spar, iron pyrites, and galena,
64 A POPULAR TREATISE ON GEMS.<br />
represented in fig. 73. In fig. 74 of zinc-blende, two rhombic<br />
dodecahedrons are united by a face of the octahedron.<br />
In the Tetragonal system, twin crystals with parallel axes<br />
Fig. 74. Fig. 75.<br />
rarely occur, but are seen in chalcopyrite, and one or two<br />
other minerals. Where the axes are inclined the plane of<br />
union is very often one of the faces of the pyramid Poo , or<br />
one of those faces that would regularly replace the polar<br />
edges of the fundamental form P. The crystals of tin ore<br />
obey this law, as seen in fig. 75, where the individuals are<br />
pyramidal, and in the knee-shaped crystal (fig. 76), where<br />
Fig. 76. Fig. 77.<br />
they are more prismatic.<br />
Hausmanite appears like fig. 77,<br />
in which the fundamental pyramid P prevails, on whose polar<br />
edges other crystals are often very symmetrically repeated.
FORM OF MINERALS. 65<br />
a central individual appearing like the support of all the<br />
others. Almost identical forms occur in chalcopyrite.<br />
In the Hexagonal system, twin crystals with parallel axes<br />
are common, as in calc-spar, chabasite, hematite, and other<br />
rhombohedric minerals. In calc-spar they often form very<br />
regular crystals, the two individuals uniting by a plane<br />
parallel to the base, so as to appear like a single crystal, as<br />
in fig. 78, where each end shows the forms ooR. R, but<br />
in a complementary position ; or in fig. 79 of two scaleno-<br />
hedrons R3 from Derbyshire. The rhombohedric crystals<br />
of chabasite often appear intersecting each other, like those<br />
of fluor spar in fig. 73. The purer varieties of quartz or<br />
Fig. 78. Fig. 79. Fig. 80.<br />
rock crystal, in consequence of the tetartohedric character<br />
of its crystallization, often exhibit twins. In these the<br />
pyramid P separates into two rhombohedrons P and z,<br />
which, though geometrically similar, are yet physically<br />
distinct. In fig. 80 the two individuals are only grown to-<br />
gether, but more commonly they penetrate each other in<br />
an irregular manner, forming apparently a single crystal.<br />
Twins with oblique axes are also common, the plane of<br />
union being usually one face of the rhombohedron. Thus<br />
in calc-spar two rhombohedrons are often joined by a face
66 A POPULAR TREATISE ON GEMS.<br />
of gll, the two axes forming an angle of 127 34'; occa-<br />
sionally a third individual is interposed in a lamellar form,<br />
as in fig. 81, when the two outer crystals become parallel.<br />
Fig. 81. Fig. 82.<br />
This latter arrangement is very common in the highly<br />
cleavable varieties of Iceland spar. When the crystals<br />
unite in a face of the rhombohedron R, fig. 82, they form<br />
an angle of 89 8', differing little from a right angle, by<br />
which the occurrence of this law is very easily recognized,<br />
especially in prismatic varieties.<br />
In the rhombic system, twin crystals with parallel axes<br />
are very rare, but those with oblique axes common, the<br />
GO P.<br />
plane of union being one of the faces of the prism<br />
Twins of this kind are very distinctly seen in arragonite,<br />
Fig. S3. Fig. 84 Fig. 85.<br />
carbonate of lead, marcasite, stephanite, mispickel, and<br />
other minerals. In arragonite the crystals partly interpen-
FORM OF MINERALS. 6-7<br />
etrate, partly are in mere juxtaposition, as in fig. 83, where<br />
the individuals are formed by the Combination ooP(Jlf) .<br />
oo Poo (A), Poo (&), and in figure 84 where several crystals<br />
of the same combination form a series with parallel planes<br />
of union ; the inner members being so shortened that they<br />
appear like mere lamellar plates producing<br />
striae on the<br />
faces Poo and ooPoo of the made. In fig. 85 four crystals,<br />
each of the combination ooP . 2Poo , having united in in-<br />
clined planes, form a circular group, returning into itself.<br />
The carbonate of lead often occurs in macles in all respects<br />
Fig. 86. Fi . ? 87.<br />
similar. In staurolite, individuals of the prismatic combition<br />
oo P . oo Poo . OP, combine either, as in<br />
fig. 86, by a<br />
face of the braehydome |Poo , with their<br />
chief axes almost at right angles; or, as in<br />
fig. 87, by a face of th brachypyramid<br />
fP|, the chief axes and the brachypinacoids<br />
(o) of the two single crystals meeting<br />
at an angle of about 60. Finally, in fig.<br />
88, two harmotome crystals of the most<br />
common combination ooPoo . ooPoo . P .<br />
Poo , intersect each other so nearly at right<br />
angles, that their principal axes seem to Fig.88.<br />
coincide, and the brachypiuacoid (q) of the one crystal
68 A POPULAR TREATISE ON GEMS.<br />
(with a rhombic striae) is parallel to the macropinacoid (q)<br />
of the other.<br />
In -the monoclinohedric system the most common macles<br />
are those in which the principal axes and the chief sections<br />
of the two crystals are parallel to each other, and conse-<br />
quently the principal axis is also the twin axis. Usually<br />
the two individuals are united by a face parallel to the or-<br />
thodiagonal chief section, as in figure 89 of gypsum, where<br />
two crystals of the combination (ooPco).ooP. P, shown<br />
in fig. 59, unite so regularly that the faces of the pinacoids<br />
(P and P') form only one plane.<br />
In a similar manner the<br />
augite crystals of the combination ooP. ooPoo . (ooPoo).<br />
P, represented singly in fig. 60, are in fig.<br />
90 united in a<br />
Fig. 89. Fig. 90. Fig. 91.<br />
macle so very symmetrical and regular that the line of<br />
junction cannot be observed on tlie face of the clinopinacoid.<br />
The two hemipyramids P (s) (like P (I) in the gypsum<br />
crystal above) form on one side a re-entering, on the other<br />
a salient angle. Hornblende, wolfram, and other minerals<br />
exhibit a similar appearance. In other cases the individuals<br />
partially penetrate each other, being, as it were, crushed<br />
together in the direction of the orthodiagonal. This mode<br />
of union is not uncommon in gypsum, and very frequent in<br />
orthoclase felspar. Two crystals of the latter, of the com-
FOKM OF MINERALS. 69<br />
bination ( ooPoo ) . ooP . OP . 2Poo , as in fig. 61 above, are<br />
often pushed sidewise into each other, as shown in fig. 91.<br />
In the triclinohedric system, some twin formations are of<br />
great importance as a means of distinguishing the triclinohedric<br />
from the monoclinohedric species of felspar. In one<br />
variety the twin axis is the normal to the brachydiagonal<br />
chief section. But in the triclinohedric felspars this sec-<br />
tion is not, as it is in the monoclinohedric species, perpendicular<br />
to the basis, and consequently the two bases form<br />
on one side a re-entering, on the other a salient angle ;<br />
whereas in the monoclinohedric felspars (where the brachydiagonal<br />
chief section corresponds to the clinodiagonal), no<br />
twin crystals can be produced in conformity to this law, and<br />
the two bases fah 1<br />
in one plane. The albite and oligoclase<br />
very often exhibit such twins, as in figure 92, where the<br />
Fig. 92.<br />
very obtuse angles formed by the faces of OP, or P and P'<br />
(as well as those of 'P'oo , or x and #'), are a very charac-<br />
teristic appearance, marking out this mineral at once as a<br />
triclinohedric species. Usually the twin formation is re-<br />
peated, three or more crystals being combined, when those<br />
in the centre are reduced to mere plates. When very nu-<br />
merous, the surfaces P and x are covered with fine striae,<br />
often only perceptible with a microscope. A second law
A POPULAR TREATISE ON GEMS.<br />
observed in triclinohedric felspars, particularly the albite<br />
and labradorite, is that the twin axis corresponds with that<br />
normal of the brachydiagonal which is<br />
situated in the plane of the base. In<br />
pericline, a variety of albite, these twins<br />
appear as in fig. 93, where the two crystals<br />
are united by a face of the basal<br />
pinacoid P, while the faces of the two<br />
brachypinacoids (Jffand M') form edges<br />
with very obtuse angles (1*73 22'), re-<br />
entering on the one side and salient on<br />
the other. These edges, or the line of<br />
Fig. 93.<br />
junction between JbTand Jtf'9 are also parallel to the edges<br />
formed by these faces and the base, or those between M<br />
and P. In this case also the macles are occasionally sev-<br />
eral times repeated when the faces appear covered with fine<br />
stria3.<br />
Irregular Aggregation of Crystals.<br />
Besides the regular unions now described, crystals are<br />
often aggregated in peculiar ways, to which no fixed law<br />
can be assigned. Thus some crystals, apparently simple,<br />
are composed of concentric crusts or shells, which may be<br />
removed one after the other, always leaving a smaller crys-<br />
tal like a kernel, with smooth distinct faces. Some speci-<br />
mens of quartz from Beeralston in Devonshire consist apparently<br />
of hollow hexagonal pyramids placed one within<br />
another. Other minerals, as fluor spar, apatite, heavy spar,<br />
and calc-spar, exhibited a similar structure by bands of dif-<br />
ferent colors.<br />
Many large crystals, again, appear like an aggregate of<br />
numerous small crystals, partly of the same, partly of different<br />
forms. Thus some octahedrons of fluor spar from<br />
Schlaggenwald are made up of small dark violet-blue cubes,
FORM OF MINERALS. 71<br />
whose projecting angles give a drusy character to the faces<br />
of the larger form. Such polysynthetic crystals, as they<br />
may be called, are very common in calc-spar.<br />
A similar, but still more remarkable formation, is where<br />
two crystals of distinct species are conjoined. Such unions<br />
of cyanite and staurolite have been long well known, and<br />
the graphic-granite exhibits a similar union between large<br />
felspar crystals and many smaller ones of mica and quartz.<br />
Forms of Crystalline Aggregates. Crystals have often<br />
been produced under conditions preventing the free de-<br />
velopment of their forms. They then compose crystalline<br />
aggregates, of which the following may be distinguished :<br />
Granular, formed of grains, generally angular, but rarely<br />
rounded or flattened. Lamellar consist of broad plates,<br />
which are tabular when of uniform thickness, lenticular<br />
when becoming thinner on the edges, icedge-shaped when<br />
sharpened towards one edge, and scaly when the plates are<br />
very small. Columnar, in which the individuals are drawn<br />
out in one direction more than in the others ; bacittary or<br />
rod-like, in which the columns are of uniform thickness ;<br />
acicular or needle-shaped,, in which they are pointed; and<br />
fibrous, in which they are very fine. In the broad-columnar<br />
the columns are, as it were, compressed, or broader in<br />
one direction than the other. The distinctions of large,<br />
coarse, small, or fine-granular ; thick or thin scaly ; straight,<br />
curved, or twisted- columnar ; parallel, diverging, or con-<br />
fused-fibrous ;<br />
and such like, are easily understood.<br />
Aggregates which have been able to crystallize, at least,<br />
with a certain degree of freedom, have been distinguished<br />
by Mohs into crystal groups and druses : the former includ-<br />
ing all unions of several imbedded crystals ; the latter those<br />
of crystals that have grown together on a common support.<br />
In the groups, crystals with their faces otherwise perfect<br />
are conjoined in various ways. Sometimes they radiate, as
72 A POPULAR TREATISE ON GEMS.<br />
it were, from a common centre, and produce spheroidal, el-<br />
lipsoidal, or other forms, frequent in gypsum, iron pyrites,<br />
and other minerals imbedded in clay. Where many such<br />
masses are united, they are named botryoidal when like<br />
bunches of grapes, mammellated where the spheres are<br />
larger and less distinct, and reniform or kidney-shaped<br />
where the masses are still larger. Some groups are partially<br />
attached by a small point ; but the mass is generally<br />
free.<br />
Crystals are often grouped in rows or in one direction,<br />
forming, when they are very small, capillary or hair-like,<br />
and filiform, thread, or wire-like forms, which are common<br />
among native metals, as gold, silver, copper, and bismuth,<br />
in silver glance and a few other materials. Sometimes the<br />
masses are dentiform, consisting of portions resembling<br />
teeth ; as is very common in silver. Often these groups<br />
expand in several directions, and produce arborescent,<br />
dendritic, foliated, feathered, or other forms, very common<br />
in copper. In these groups, however, a certain dependence<br />
on the crystallographic character of the species may be<br />
observed. The lamellar minerals often form fan-shaped,<br />
wheel-like, almond-shaped, comb-like, or other groups.<br />
The fibrous types, again, are disposed in parallel or diverging<br />
bundles, or in radiating, stellar, and other masses.<br />
Coralloidal (like coral), fruticose (like cauliflower), and other<br />
forms, have also been observed.<br />
In druses, many crystals rise side by side from a common<br />
support sometimes ;<br />
only the granular mass composed of<br />
their united bases, at other times some distinct body. The<br />
form of a druse is determined by that of the surface on<br />
which it grows, and consequently is often very irregular or<br />
wholly accidental. Where completely inclosed they have<br />
been named drusy cavities, and when of a spheroidal form,<br />
geodes. A drusy crust, again, consists of a thin layer of
FORM OF MINERALS. 73<br />
small crystals investing the surface of a large crystal or" of<br />
some othep body.<br />
The minute or cryptocrystalline minerals form similar<br />
aggregates. In the globular or the oolitic, the minute crystals<br />
often appear to radiate from a centre, or form concen-<br />
tric crusts. Somewhat -similar are the stalactites and sta-<br />
lagmites, in which the mineral, especially rock-salt, lime-<br />
stone, chalcedony, opal, limonite, has been deposited from<br />
a fluid dropping slowly from some overhanging body. In<br />
this case the principal axis of the figure, generally a hollow<br />
tube, is vertical, while the individual parts are arranged at<br />
right angles to this direction. In other cases the mineral<br />
has. apparently been deposited from a fluid mass moving<br />
slowly in a particular direction, which may be regarded as<br />
the chief axis- of the figure, while the axes of the indi-<br />
vidual crystals may assume a different position.<br />
By far the largest masses of the mineral kingdom have,<br />
however, been produced under conditions in which a free<br />
development of their forms was excluded. This has been<br />
the case with the greater portion of the minerals composing<br />
rocks or filling veins and dykes. The structure of these<br />
masses on the large scale belongs to geology, but some<br />
varieties of the texture visible even in hand specimens may<br />
be noticed. The individual grains or masses have seldom<br />
any regular form, but appear round, long, or flat, according<br />
.to circumstances, and as each has been more or less checked<br />
in the process of formation. Even then, however, a cer-<br />
tain regularity in the position of the parts is often observ-<br />
able, as in granite, in which the cleavage planes, and con-<br />
sequently the axes of the felspar crystals, are parallel.<br />
Where these grains are all pretty similar in size and shape,<br />
the rock is named massive when they are small, or granular<br />
when they are larger and more distinct. Sometimes the rock<br />
becomes slaty, dividing into thin plates ;<br />
4<br />
or concretionary,
74 A POPULAR TREATISE ON 'GEMS.<br />
forming roundish masses ; at other times the interposition<br />
of some foreign substance (gas or vapor) has renderetl it<br />
porous, cellular or vesicular, giving rise to drusy cavities.<br />
These cavities are often empty, but have occasionally been<br />
filled by other minerals, when the rock is named amygdaloidal,<br />
from the almond-like shape of the inclosed masses.<br />
Many of the above external forms appear also in the<br />
amorphous solid minerals, in which no trace of individual<br />
parts, and consequently of internal structure, is observable.<br />
They are not unfrequently. disposed in parallel or concen-<br />
tric layers, of uniform or distinct colors ; and may assume<br />
spherical, cylindrical, stalactitic, and other appearances.<br />
Pseudomorphism. When the substance of one mineral<br />
assumes the external form of some other mineral, it is named<br />
a.pseudomorph. In some named incrusting pseudomorphs<br />
the original crystal is covered by a rough or drusy surface<br />
of the second mineral, frequently not thicker than paper.<br />
Occasionally the first crystal has been removed, and noth-<br />
ing but the shell remains ;<br />
or the cavity has been filled by<br />
a distinct mineral species, or a crystalloid, as it may .be<br />
named, forming an exact representation of the original, but<br />
of a different substance.<br />
More commonly the new mineral substance has gradually<br />
expelled the old, and replacing it, as it were, atom by atom,<br />
has assumed its exact form. In other cases not the whole<br />
substance of the original crystal, but only one or more of<br />
its elements, has been changed, or the whole matter has<br />
remained, but in a new condition. Thus arragonite crystals<br />
have been converted into calc-spar, the chemical com-<br />
position of both being identical ; or gaylussite<br />
has been<br />
changed into calc-spar, andalusite into cyanite, by the loss<br />
of certain elements. On the other hand, anhydrite be-<br />
comes gypsum, red-copper .<br />
ore malachite, by addition of<br />
new matter. Or-tho elements are partially changed, as
. FORM OP MINERALS. 75<br />
felspar T-to kaolin, quartz or pearl spar into talc, iron pyrites<br />
or iron glance into brown-iron ore> azurite into malachite,<br />
augite into green earth. The true nature of such bodies is<br />
shown by the internal structure, having no relation to the<br />
external form or apparent system of crystallization.<br />
The process of petrifaction of organic bodies is in reality<br />
a species of pseud oinorphic formation, and lias been pro-<br />
duced in all the above modes. External and internal casts<br />
of organic bodies are not uncommon. In other cases the<br />
original substance has been replaced by some mineral which<br />
has preserved not merely the external form, but ev'en the<br />
"minutest detail of internal structure ; so that the different<br />
kinds of wood have been distinguished in their silicified<br />
trunks. The most common petrifying substances are silica<br />
and carbonate of lime. In encrynites, echinites, belemnites,<br />
and other fossils, the crystals of calc-spar often occur in<br />
In some varieties of petrified wood<br />
very regular positions.<br />
both the ligneous structure and the cleavage of the calc-<br />
spar are observable.<br />
Different from the above are mineralized bodies, in which<br />
the original structure is still retained, but their chemical<br />
nature partially changed. In these a complete series may<br />
be often traced, as from wood or peat, through the varie-<br />
ties of brown coal, common coal, anthracite, and graphite,<br />
perhaps even to the diamond.<br />
CHAPTER II.<br />
PHYSICAL PROPERTIES OF MINERALS.<br />
THE physical characters of minerals comprehend, 1st.<br />
Those properties derived from the nature of the substance<br />
itself, as coherence, mode of fracturej elasticity, and density
7G A POPULAR TREATISE ON" GEMS. .<br />
or specific gravity ; 2cl Those phenomena called forth in<br />
minerals by the influence of some external power or agent,<br />
as their optical, electric, or thermal relations; and, 3d.<br />
Other characters depending on the personal sensation of<br />
the observer on his taste, smell, and touch. All these<br />
properties furnish useful characters in distinguishing and<br />
describing mineral species.<br />
Cleavage and Fracture.<br />
In many species there are certain planes at right* angles<br />
to which cohesion seems to be at a minimum, so that the<br />
mineral separates along or parallel to these planes far more<br />
readily than in any other direction. This property is named<br />
cleavage, and these planes cleavage-planes. They have a<br />
strictly definite position, and do not show any transition or<br />
gradual passage into the greater coherence in other direc-<br />
tions. The number of these parallel cleavage-planes is alto-<br />
gether indefinite ; so that the only limit that can be as-<br />
signed to the divisibility of some minerals, as gypsum and<br />
mica, arises from the coarseness of our instruments.<br />
These minima of coherence or cleavage-planes are always<br />
parallel to some face of the crystal, and similar equal minima<br />
occur parallel to every other face of the same form.<br />
Hence they are always equal in number to the faces of the<br />
form, and the figures produced by cleavage agree in every<br />
point with true crystals, except that they are artificial.<br />
They are thus most simply and conveniently described by<br />
the same terms and signs as the faces of crystals. Some<br />
minerals cleave in several directions parallel to the faces of<br />
different forms, but the cleavage is generally more easily<br />
obtained and more perfect in one direction than in the<br />
others, This complex cleavage is well seen in calc-spar<br />
and fluor spar, and very remarkably in zinc-blende, where
PHYSICAL PROPERTIES OF MINERALS. 77<br />
it takes place in no less than six directions. As in each of<br />
these the division may be indefinitely continued,<br />
it is clear<br />
that no lamellar structure in any proper sense can be as-<br />
signed to the mineral. All that can be affirmed is, that<br />
atoms have less coherence in the normal of these<br />
contiguous<br />
planes than in other directions. When the cleavage takes<br />
place in three directions, it of course produces a perfect<br />
crystal form, from which the system of crystallization and<br />
angular dimensions of the species may be discovered, and<br />
is thus often of very great importance.<br />
The common cleavage in the different systems is as fol-<br />
lows, those of most frequent occurrence being put in italics.<br />
(1.) In the tessera), Octahedric, O, along<br />
the faces of the<br />
octahedron ; Bexahedric, ooOoo , alonij those of the cube ,<br />
and Dodecahedric, o>O. (2.) In the tetragonal system,<br />
Pyramidal, P or 2Poo ; Prismatic, ooP or ooPoo; or Ba-<br />
sal, OP. (3.) In the hexagonal system<br />
with holohedric<br />
forms, Pyramidal, P or P2 ; Prismatic, ooP or ooP2 or<br />
;<br />
Basal, OP with rhombohedral ;<br />
forms, EhomboJiedric, R ;<br />
Prismatic, oo R ; or Basal, OR. (4.) In the rhombic sys-<br />
tem, Pyramidal, P; Prismatic, ooP; Makro or Brachy-<br />
domatic, Poo or Poo; Basal, OP; Macrodiagonal, ooPoo;<br />
or Br'achy'diagonal, ooPoo .<br />
(5.) In the monoclinohedric<br />
system, Hemipyramidal, P or P; Prismatic, ooP; Clinodomatie<br />
(P^o) ; Hemidomatic, Poo or Poo; Basal, OP;<br />
Orthodiagonal, ooPoo; or Clinodiagonal (ooPoo). (6.)<br />
In the triclinohedric system, Hemiprismatic, ooP' oroo'P;<br />
Hemidomatic either along the macrodome or brachydome ;<br />
Basal, OP; Macrodiagonal, ooPoo; or Br achydiagonal,<br />
00 P 00. .<br />
In some minerals the cleavage is readily procured ; in<br />
others only with extreme difficulty.<br />
The planes produced<br />
also vary much in their degree of perfection, being highly<br />
perfect in some, as mica and gypsum ; imperfect in others,
78 A POPULAR TREATISE ON GESTS.<br />
as garnet and quartz. In a very few crystalline minerals<br />
cleavage-planes can hardly be said to exist. Cleavage must<br />
be carefully distinguished from the planes of union in twin<br />
crystals, and the division-planes in the laminar minerals.<br />
Fraeture surfaces are formed when a mineral breaks in<br />
a direction different from the cleavage-planes. They are<br />
consequently most readily observed when the cleavage is<br />
least perfect. The form of the fracture is named conchoidal<br />
when composed of concave and convex surfaces like shells,<br />
even when nearly free from inequalities. The character of<br />
the surface is smooth / or splintery when covered by small<br />
wedge-shaped splinters adhering by the thicker end; or<br />
hackly when covered by small slightly-bent inequalities, as<br />
in iron and other malleable bodies ;<br />
only fine dust.<br />
Hardness and Tenacity.<br />
or earthy when it shows<br />
The hardness of minerals, or their power of resisting any<br />
attempt to separate their parts, is also an important charac-<br />
ter. As it differs considerably in the same species, accord-<br />
ing to the direction and the surface on which the trial is<br />
made, its accurate determination is difficult, and the utmost<br />
that can usually be obtained is a mere approximation found<br />
by comparing different minerals one with another. For<br />
this purpose Mobs has given the following scale :<br />
1. Talc, of a white or greenish color.<br />
2. Rock-salt, a pure cleavable variety, or semi-transparent uncrystallizea<br />
gypsum,, the transparent and crystallized varieties being generally too soft.<br />
8. Calcareous spar, a cleavable variety.<br />
4. Fluor spar, in which the cleavage is distinct.<br />
5. Apatite,\.\\Q asparagus-stone, or phosphate of lime.<br />
6. Adularia felspar, any cleavable variety.<br />
7. Rock- crystal, a transparent variety.<br />
8. "Prismatic topaz, any simple variety.<br />
9. Corundum, from India, which affords smooth cleavage surfaces.<br />
10. The Diamond.
PHYSICAL PROPERTIES OF MINERALS. 79<br />
Two other degrees are obtained by interposing foliated<br />
mica between 2 and 3, and scapolite, a crystalline variety,<br />
between 5 and 6. The former is .numbered 2'5, the lat-<br />
ter 5*5.<br />
To ascertain the hardness of a mineral, first try which of<br />
the members of the scale is scratched by it, and in order to<br />
save the specimens, begin with the highest numbers, and<br />
proceed downward, until reaching one which is scratched.<br />
Then take a finer hard file, and draw along its surface, with<br />
the least possible force, the specimen to be examined, and<br />
also that mineral in the scale whose hardness is immediately<br />
above the one which has been scratched. From the resist-<br />
ance they offer to the file, from the noise occasioned by<br />
their passing along it, and from the quantity of powder left<br />
on its surface, their relative hardness is deduced. When,<br />
after repeated trials, we are satisfied to which member of<br />
the scale of hardness the mineral is most nearly allied, we<br />
say its hardness (suppose it to be felspar) is equal to 6, and<br />
write after it H.=:6'0. If the mineral do not exactly cor-<br />
respond with any degree of the scale, but is found to be<br />
between two of them, it is marked by the lower with a de-<br />
cimal figure added. Thus, if more than 6 but less than 7,<br />
it is expressed H.=6'5. In these experiments we must be<br />
careful to employ specimens which nearly agree in form<br />
and size, and also as much as possible in the shape of their<br />
angles.<br />
Where the scale of hardness is wanting, or for a first<br />
rough determination, the following experiments may<br />
serve :<br />
Every mineral that is scratched by the finger-nail has H. = 2-5 or less.<br />
Minerals that scratch copper have H. = 3 or more.<br />
Polished white iron has H. = 4-5.<br />
JVindow-glass has H. = 5 to 5*5.<br />
Steel point or file has H. = 6 to 7.<br />
Hence every mineral that will cut or scratch with, a good penknife has<br />
H. less than 6.
80 A POPULAR TREATISE ON GEMS.<br />
Flint has H. = 7, and only about a dozen minerals, including the precious<br />
atones or gems, are harder.<br />
Precious stones have latterly been divided and arranged<br />
according to their hardness, in the following three classes<br />
1. HARD OEMS ; OB THOSE HARDER THAN QUARTZ.<br />
Diamond. Topaz.<br />
Sapphire.<br />
Emerald.<br />
Ruby. Hyacinth.<br />
Chrysoberyl.<br />
Essonite.<br />
Spinelle.<br />
Garnet.<br />
2. SEMI-HARD JEWELS.<br />
Eock Crystal. Opal.<br />
Amethyst. Chrysolite<br />
Chalcedony.<br />
Lazulite.<br />
Carnelian, and other Obsidian,<br />
similar ones. Turquoise.<br />
3. SOFT PRECIOUS STONES.<br />
Those softer than Fluor-spar ; Malachite, Amber, and Jet.<br />
Closely allied to hardness is the TENACITY of minerals, of<br />
which the following varieties have been distinguished : A<br />
mineral is said to be brittle when, as in quartz, on attempting<br />
to cut it with a knife, it emits a grating noise, and the<br />
particles fly away in the form of dust. It is sectile or mild<br />
when, as in galena and some varieties of mica, on cutting,<br />
the particles lose their connection in a considerable degree ;<br />
but this takes place without noise, and they do not fly off,<br />
but remain on the knife. And* a mineral is said to be soft<br />
or 'ductile when, like native gold or lead, it can be cut into<br />
slices with a knife, extended under the hammer, and drawn<br />
into wire. From tenacity it is usual to distinguish frang I-<br />
bility) or the resistance which minerals oppose when we at-<br />
tempt to break them into pieces or fragments. This prop-<br />
erty must not be confounded with, hardness. Quartz is<br />
hard, and hornblende comparatively soft ; yet<br />
><br />
the latter is
PHYSICAL PROPERTIES OP MINERALS. 81<br />
||<br />
more difficultly frangible than the former.<br />
Flexibility<br />
again expresses the property possessed by some minerals<br />
of bending without breaking. They are elastic, like mica,<br />
if, when bent, they spring back again into their former di-<br />
rection ;<br />
or merely flexible, when they can be - bent in dif-<br />
ferent directions without breaking, but remain in their new<br />
position, as gypsum, talc, asbestus, and all malleable min-<br />
erals.<br />
Specific Gravity.<br />
The density or the relative weight o*f a mineral, com-<br />
is named<br />
pared with an equal volume of pure distilled water,<br />
its specific gravity. This is a<br />
most important character for dis-<br />
tinguishing minerals,<br />
as it varies<br />
considerably in different species,<br />
and can be readily ascertained<br />
with much accuracy, and in many<br />
cases without at ah 1<br />
injuring the<br />
specimen. The whole process con-<br />
sists in weighing the body, first in<br />
air, and then immersed in water,<br />
the difference in the weight being<br />
that of an equal bulk of the latter<br />
fluid. Hence, assuming, as is com-<br />
monly done, the specific gravity<br />
of pure distilled water to be equal<br />
. Fig. 94.<br />
to 1 or unity, the specific gravity<br />
(G) of the other body is equal to its weight in air (w), divided<br />
by the loss or difference (G) of weight in water (or<br />
G=5. A simple and portable instrument for finding the<br />
specific gravity is a hydrometer of Nicholson, fig.<br />
94. A<br />
delicate hydrostatic balance gives the gravity with far more<br />
40
82 A POPULAR TREATISE ON GEMS.<br />
accuracy; and even a good common balance is often pieferable.<br />
The mineral may be suspended from one arm or<br />
scale by a fine silk thread or hair, and its weight ascer-<br />
tained, first in the air, and then in water.<br />
There are a few precautions necessary to insure accuracy.<br />
Thus, a pure specimen must be selected which is not intermixed<br />
with other substances, and when weighed in air it<br />
should be quite dry. It must also be free from cavities,<br />
and care must be taken that when weighed in water no<br />
globules of air adhere to its surface, which render it lighter.<br />
If the body imbibos moisture, it should be allowed to remain<br />
till fully saturated before determining its weight when<br />
immersed, and it is sometimes even necessary to boil the<br />
specimen in order to expel the air from its pores. Small<br />
crystals or fragments, whose freedom from mixture can be<br />
seen, are best adapted for this purpose. The specimen<br />
experimented on should not be too heavy ; thirty grains<br />
being enough where the gravity is low, and even less where<br />
it is high. It is also of importance to repeat the trial, if<br />
possible with different -specimens, which will show whether<br />
any cause of error exists, and to take the mean of the<br />
whole. A correction should be made for the variation of<br />
the temperature of the water from 60 Fahr., which is that<br />
usually chosen as the standard in mineralogical works.<br />
Where the difference, however, does not exceed ten or fif-<br />
teen degrees, this correction may be neglected, as it only<br />
affects the third or second decimal figure of the result.<br />
By determining the specific gravity of minerals with the<br />
hydrostatic balance, we proceed, for instance : an unknown,<br />
mineral having been weighed first in the air, and then fast-<br />
ened by means of a hair and weighed in water. Such as<br />
in the air 17 "65; in water 12*35. The loss in water is,<br />
therefore, 5 '30; and this number indicates the loss of so<br />
much bulk of water displaced by the mineral putting the
PfiYSICAL PROPERTIES OF MINERALS. 83<br />
specific gravity of water 1*00: x dividing 5 into 17'65,<br />
make it equal to 3 '5 3, which is the exact specific gravity<br />
of the mineral, and which is that of essonite. Instead of a<br />
hydrostatic balance, we may as "well use Nicholson's hydrometer,<br />
a simple and A^ery convenient instrument, cot><br />
sisting of a hollow glass cylinder (A), and two dishes (B<br />
and C) filled with lead, in order to keep the instrument<br />
upright. The hydrometer is put-in a glass vessel (E), filled<br />
with water, and used as follows :<br />
1st. The weight is determined which is required to sink<br />
the instrument to the mark D in water.<br />
2d. The mineral is put in the dish A over the weight<br />
noted, that 'is required, in addition to the mineral, to sink<br />
the hydrometer to D.<br />
3d. The same experiment is repeated by putting the<br />
mineral, after being moistened and washed with water, in<br />
the dish C ; and now is A B the weight of the mineral in<br />
the air, and B b the weight of a quantity of water equal<br />
in volume to that of the mineral.<br />
For instance, let A = 32'8<br />
B = 7-3<br />
C = 15'8<br />
there is (A b) 32*8 7*3 = 25*5 the weight of the mineral<br />
in the air.<br />
(C b) 15*8 7*3 = 8*5 the weight of an equal quantity<br />
of water, and proceed 8*5 : 25*5 = 1 : x<br />
8-5<br />
= 3*00, which is the proper specific<br />
gravity. For determining the specific gravity of substances<br />
or minerals lighter than water, or which float in water, it<br />
is necessary to adhere to the same method by the hydrometer.<br />
A heavier body, such as lead, after determining the
84 A POPULAR TREATISE ON GEMS.<br />
difference of weight, within or without the water, of both<br />
together, and then of the heavier body alone, the specific<br />
gravity of the lighter substance is the result. And for determining<br />
the specific gravity of liquids, by means of the<br />
hydrostatic balance, a glass ball is applied to one of the<br />
arms (its<br />
loss of weight in pure water being known), and,<br />
dipping the same in the liquid to be examined, any addition<br />
and abstraction will result in the specific gravity of the<br />
liquid. The hydrometers of Beaume for the different<br />
liquids to be examined, are employed with satisfactory<br />
results.<br />
That the specific gravity has been known as far back as<br />
the thirteenth century, and applied by the Oriental nations<br />
for determining the character of precious stones, is sufficiently<br />
proved by a work written in that century by Mohammed<br />
Ben Manner. In fact, the specific gravity is often,<br />
in connection with the color, quite essential in determining<br />
a gem.<br />
Optical Properties of Minerals.<br />
There are few more interesting departments of science<br />
than the relations of mineral bodies to light, and the modi-<br />
fications which it undergoes either when passing through<br />
them or when reflected from their surface. In this place,<br />
however, we can only notice these phenomena so far as<br />
they point out distinctions in the internal constitution of<br />
minerals, or furnish characters for distinguishing one species<br />
from another.<br />
Minerals, and even different specimens of the same spe-<br />
cies, vary much in pellucidity or in the quantity of light<br />
which can pass through them. Some transmit so much<br />
light, that small objects can be clearly seen, or letters read<br />
when placed behind them, and are named transparent.<br />
They are semi-transparent when the object is only seen
PHYSICAL PROPERTIES OF MINERALS. 85<br />
and translucent when the light<br />
dimly, as through a cloud ;<br />
that passes through it is so obscured that the objects can<br />
be no longer discerned. Some minerals are only thus trans<br />
lucent on the thinnest edges, and hi others even these trans<br />
mit no light, and the body is named opaque or untranspa<br />
rent. These degrees pass gradually into each other, and<br />
cannot be separated by any precise line ; and' this is also<br />
the case in nature, where some minerals pass through the<br />
whole scale, as quartz, from the fine transparent rock-crystal<br />
to opaque dark-black varieties. Such minerals may be<br />
described generally as pellucid. This change often arises<br />
from some mixture in their composition, especially of me-<br />
tallic substances. Perfect opacity is chieny found in the<br />
metals or their compounds with sulphur, though even these<br />
seem to transmit light when reduced to Iamina3 of sufficient<br />
thinness.<br />
Double Refraction. When a ray of light passes ob-<br />
liquely from one medium into another of different density,<br />
it is bent or refracted from its former course. The line<br />
which it then follows forms an angle with the perpendicular,<br />
which in each body bears a certain proportion to<br />
that at which the ray fell upon, it ; or, as definitely stated,<br />
the sine of the angle of refraction has a fixed ratio to the<br />
sine of the angle of incidence, this ratio being named the<br />
index of refraction. This simple refraction is common to all<br />
transparent bodies, whether crystalline, amorphous, or fluid ;<br />
but some crystals produce a still more remarkable result.<br />
The ray of light which entered them as one is divided into<br />
two rays, each following different angles, or is doubly re-<br />
fracted. In minerals of the tesseral system this property<br />
does not exist, but it has been always observed in minerals<br />
belonging to the other systems, though in many only after<br />
they have been cut in a. particular manner, or have been<br />
otherwise properly prepared. It is most distinctly seen in
86 A POPULAR TREATISE ON GEMS.<br />
crystals of calc-spar, especially in the beautiful transparent<br />
variety from Iceland, in which it was first observed and<br />
described by Erasmus Bartholin in a work published at<br />
in 1669.<br />
Copenhagen<br />
The subjoined figure will illustrate this singular proper-<br />
ty. It represents a<br />
rhomb of Iceland<br />
spar, on the surface<br />
of which a ray of<br />
light E r falls. As<br />
seen in the figure,<br />
this ray divides into<br />
two, one of which<br />
rod follows the ordi-<br />
nary law of refraction,<br />
or the sines of<br />
the angles of incidence and refraction maintain a constant<br />
ratio. This is named the ordinary ray O. The other,<br />
hence named the extraordinary ray E, does not obey the<br />
usual law of the sines, and has no general index of refrac-<br />
tion. In the plane perpendicular to the axis it is most<br />
widely separated from the ordinary ray, but in others ob-<br />
lique to it approaches nearer to O, and in one at right<br />
angles coincides, or there is no double refraction. This<br />
plane, or rather direction, in which there is no double refraction,<br />
is named the optical axis of the crystal, or the<br />
axis of double refraction. Now, in certain minerals, it is<br />
found that there is only one plane with this property, where-<br />
as in others there are two such planes, and they have in<br />
consequence been divided into monoaxial and binaxial. To<br />
the former (monoaxial) belong all crystals of the tetrago-<br />
nal and hexagonal systems ; to the latter (binaxial) all<br />
those of the three other systems. In the former the optic<br />
axis coincides with, or is parallel to, the crystallographic
PHYSICAL PKOPEKTIES OF MINERALS. 87<br />
chief axis. In some crystals the index of refraction for the<br />
extraordinary ray E is greater than for the ordinary ray O ;<br />
and in others it is smaller. The former are said to have<br />
positive (or attractive), the latter negative (or repulsive),<br />
double refraction. Quartz is an example of the former,<br />
the index of refraction, according to Malus, being for O=<br />
T5484, for E=l*5582; and calc-spar of the latter, the<br />
index of O being= 1*6543, of E=l*4833. The index of<br />
E is in both cases taken at its maximum.<br />
According to Dufrenoy, the following<br />
table shows the<br />
index of refraction of a great number of minerals :<br />
Chromate of lead ................................ 2-500 to 2-974<br />
Diamond ........................................ 2-439 to 2'755<br />
Native sulphur ................................... 2-115<br />
Carbonate of lead ................................. 2-084<br />
Zircon ........................................... 1-950<br />
Garnet ........................................... 1-815<br />
Spinelle .......................................... 1-812<br />
Blue corundum (sapphire).. . ...................... 1*794<br />
Red<br />
White<br />
"<br />
"<br />
(ruby) ...... '. ..................... 1-779<br />
(sapphire) ........................ 1-768<br />
Adularia ......................................... 1-764<br />
Cymophane (oriental chrysolite) .................... 1-760<br />
Boracite .......................................... 1-701<br />
Carbonate strontia ................................ 1*700<br />
Carbonate lime i extraordinary ray<br />
( ordinary ray .......................... 1-693<br />
Arragomte {<br />
i extraordinary ray ..................... I'o3o<br />
one of the rays .................... 1*635<br />
(<br />
Sulphate baryta ,<br />
the other ray ..................... 1'620<br />
J<br />
J<br />
{ one of the rays ..................... 1*640<br />
Yellow topaz -I<br />
..<br />
,<br />
tfon<br />
{ the other ray ....................... 1 '632<br />
White topaz ...................................... l'10<br />
the rays ....................... 1'624<br />
J<br />
ie<br />
i ordinary ray<br />
1 extraordinary ray<br />
* 1*642<br />
1*663<br />
r ordinary ray<br />
Quartz<br />
{ extraordinary ray<br />
1'548<br />
*..1'558
'<br />
88 A POPULAR TREATISE ON GEMS.<br />
Eock salt 1-557<br />
Chalcedony<br />
Gypsum<br />
Opal<br />
1'553<br />
1 '525<br />
1-479<br />
Borax . 1 '475<br />
Alum 1'457<br />
Fluor spar<br />
1*486<br />
The higher the index of refraction, the more valuable<br />
appear to be the individual minerals, as may be seen by<br />
the corundum and topaz.<br />
Double refraction, whether positive or negative, being<br />
inherent in the respective mineral substances, forms a very<br />
important distinctive character, and the following minerals<br />
are arranged according to this property :<br />
CRYSTALS WITH ONE AXIS AND NEGATIVE DOUBLE EEFBACTION.<br />
Iceland spar.<br />
Dolomite.<br />
Anatase.<br />
Tourmaline.<br />
Carbonate iron. . Kubellite.<br />
Carbonate zinc. Corundum.<br />
Meionite. Emerald.<br />
Somervillite. Phosphate lime.<br />
Edingtonate.<br />
Idocrase.<br />
Wernerite. Mellite.<br />
Mica. Arseniate copper.<br />
Phosphate lead. Arseniate "<br />
Nepheline.<br />
Eed silver.<br />
Molybdate<br />
"<br />
Dioptase.<br />
Cinnabar.<br />
Alum.<br />
CRYSTALS WITH ONE AXIS AND POSITIVE DOUBLE REFRACTION.<br />
Zircon. Hydrate magnesia.<br />
Quartz.<br />
Eutil.<br />
Hydroxide iron. Oxahverite.<br />
'Oxide tin. Calcareous Scheelite.<br />
Apophyllite.<br />
Iron.<br />
It should be observed that the optic axes are not single<br />
lines, but directions parallel to a line, or innumerable par-
PHYSICAL PROPERTIES OF MINERALS. 89<br />
allel lines, passing through every atom of the crystal. It<br />
is also important to remark that this property divides the<br />
systems of crystallization into three precise groups, the<br />
tesseral, with single refraction ; the tetragonal and hexagonal,<br />
with double refraction, and monoaxial ; the other three<br />
systems also double, but binaxial. It is therefore of use to<br />
determine the system to which a mineral belongs, but is<br />
not of great value as a character for distinguishing species.<br />
Polarization of Light. Intimately connected with this<br />
property is that of the polarization of light, which being<br />
more easily and precisely observable than double refraction,<br />
is in many cases of higher value as a mineralogical character.<br />
By this term is meant a peculiar modification which a ray<br />
of light undergoes, in consequence of which its capability<br />
of being transmitted or reflected towards particular sides<br />
is either wholly or partially destroyed. Thus, if from a<br />
transparent prism of tourmaline two thin plates are cut<br />
parallel to its axis, they will transmit light, as well as the<br />
prism itself, when" they are placed above each other with<br />
the chief axis of both in the same direction. But when<br />
the one slip of tourmaline is turned at right angles to the<br />
other, either no light at all or very little is transmitted, and<br />
the plates consequently appear black. Hence, in passing<br />
through the first slip the rays of light have acquired a pe-<br />
culiar property, which renders them incapable of being<br />
transmitted through th*e second, except in a parallel posi-<br />
tion, and they are then said to be polarized.<br />
The same<br />
property is acquired by a ray of light when reflected, at<br />
an angle of 35^ (or angle of incidence 54^), from a plate<br />
of glass, one side of which is blackened, or from some<br />
other non-metallic body. When such a ray falls on a<br />
second similar mirror at an equal angle, but so that the<br />
plane of reflection in the second is at right angles to that<br />
in the first, it is no longer reflected, but wholly absorbed.
90 A POPULAR TREATISE ON GEMS.<br />
When, on the other hand, the planes of reflection are<br />
parallel, the ray is wholly and at any intermediate angle<br />
partially reflected. A ray of light polarized by reflection<br />
is also incapable of transmission through a tourmaline slip<br />
in one position, which, however, is' at right angles to that<br />
in which a ray polarized by passing through another slip<br />
is not transmitted.<br />
In order to observe the polarization of light, a very sim-<br />
ple instrument will<br />
be found useful (fig.<br />
96). At one end of<br />
a horizontal board<br />
B a black mirror a<br />
is fixed. In the<br />
middle is a pillar<br />
to which a tube c d<br />
is fastened, with its<br />
axis directed to the<br />
mirror at an angle<br />
of 35. On the<br />
lower end is a cover c, with a small hole in the centre, and<br />
at the upper end another cover with a small black mirror<br />
m attached to it by two arms, as in the figure, and also at<br />
an angle of 35 . With this instrument the mirror m can<br />
be so placed in relation to a that the planes of reflection<br />
shall have any desirable inclination to exhibit the simple<br />
polarization of light.<br />
Fig. 96.<br />
. This instrument furnishes a simple test whether minerals<br />
that cleave readily into, thin lamella? are optically mono-<br />
axial or binaxial. Place the two mirrors with their, polarization-planes<br />
at right angles, and fix a plate of the mineral<br />
with a little wax over the hole c, and then observe what<br />
takes place in the second mirror during the time that the<br />
cover c is turned round. If the mineral belongs to the bi
PHYSICAL PROPERTIES OP MINERALS. 91<br />
naxial system, the light from the first mirror , in passing<br />
through it, is doubly refracted and has its polarization<br />
changed, and consequently can be again reflected from the<br />
second mirror m, and in each revolution of.c will show four<br />
maxima and four minima of<br />
intensity. If, on the contrary,<br />
the mineral is monoaxial,\the<br />
ray will pass through the lamina<br />
unaltered, and will not be<br />
reflected from the second mir-<br />
ror in any position of c.<br />
Another beautiful phenom-<br />
enon of polarized light, in like<br />
manner connected with the<br />
crystalline structure of minerals,<br />
is the colored rings which<br />
Fig. 98. Fig. 99.<br />
laminse of the doubly-refracting species, when of a proper<br />
th ckness, exhibit in certain positions. These rings are
92 A POPULAR TREATISE ON GEMS.<br />
easily seen in the above apparatus by interposing a thir:<br />
plate of gypsum or mica between the two mirrors. When<br />
the interposed plate belongs to a monoaxial mineral, there<br />
is seen in the second mirror a system of circular concentric<br />
colored rings intersected by a black cross (fig. 97). If the<br />
mineral is binaxial, one or two systems of elliptical colored<br />
rings appear, each intersected by a black stripe (fig. 98).<br />
In certain cases this stripe is curved, or the two systems of<br />
rings unite in a lemniscoidal form (fig. 99). When the<br />
planes of polarization are parallel, the<br />
black cross and stripe appear white<br />
.(fig. 100), showing<br />
that in this direc-<br />
tion the crystals act like singly-refract-<br />
ing minerals. Quartz, again, in close<br />
relation to its system of 'crystalliza-<br />
tion, exhibits a Circular polarization<br />
of splendid prismatic colors, which,<br />
on turning the plate, change in each<br />
point in the order of the spectrum,<br />
from red to yellow, green, and blue. In order to produce<br />
these changes, however, in some specimens the plate must-<br />
be turned to the right, in others to the left, showing a dif-<br />
ference in the Crystalline structure.<br />
Pleochroism. Closely connected with double refraction<br />
is that property of transparent minerals named pleochroism<br />
(many-colored), in consequence of which they exhibit dis-<br />
tinct colors when viewed by transmitted light in different<br />
directions. Crystals of the tesseral system<br />
do not show<br />
this property ; while in those of the other systems it ap-<br />
pears in more or less perfection ;<br />
and in the tetragonal and<br />
hexagonal minerals as dichroism (two colors), in the rhombic<br />
and clinohedric systems as trichroism (three colors).<br />
In most cases these changes of color are not very decided,<br />
and appear rather as different tints or shades than as dis-
PHYSICAL PKOPERTIKS OF MINERALS. 9c<br />
tinct colors. The most remarkable of dichromatic minerals<br />
are the magnesian mica from Vesuvius, the tourmaline and<br />
ripidolite ; of trichromatic, the iolite, the andalusite from<br />
Brazil, the diaspore from Schemnitz, and the axinite.<br />
Change of Colors Changing Colors Iridescence.<br />
Some crystalline minerals exhibit a very lively play or<br />
change of colors from reflected light in certain Directions.<br />
It is well seen in many various hues on the cleavage-planes<br />
of Labrador felspar, and seems produced by a multitude of<br />
very thin quadrangular pores, interposed in the mineral<br />
like minute parallel lamina?. On the cleavage-planes of the<br />
hypersthene it appears copper-red, and is occasioned by<br />
numerous small brown or black laminae of some foreign<br />
O<br />
substance interposed in a parallel position between -the<br />
planes of the hypersthene. The chatoyant, or changing<br />
colors of the sun-stone, arise from scales of iron-glance simi-<br />
larly interposed. The play of color in the noble opal seems<br />
to be produced very nearly in the same manner with that<br />
in the labradorite. A similar opalescence is seen in certain<br />
minerals when cut in particular forms. In the" sapphire,<br />
cut hemispherically over the chief axis, it appears like a<br />
star with six rays ; in certain varieties of chrysoberyl and<br />
adularia it has a bluish tint ;<br />
and is also very remarkable in<br />
the cat's-eye variety of quartz. Iridescence often arises<br />
from very fine fissures, producing semicircular arches of<br />
prismatic tints, which, like the colors of thin plates in gen-<br />
eral, are referred to the interference of light.<br />
Lustre and Color.<br />
:<br />
"^ ;'<br />
"<br />
* .<br />
Though these properties admit of no precise or mathematical<br />
determination, they are of considerable value in
94 A POPULAR TREATISE ON GEMS.<br />
mineralogy. One highly important distinction founded on<br />
them is that of minerals of metallic and non-metallrc aspect<br />
or character. This distinction can hardly be described in<br />
words, and the student will best learn to distinguish metallic<br />
colors and lustre from non-metallic by observing them<br />
in nature. Transparency and opacity nearly coincide with<br />
this division, the metallic minerals being almost constantly<br />
opaque ; the non-metallic more or less transparent. Min-<br />
erals which are perfectly opaque, and show metallic color<br />
and lustre, are named metallic; those with only two of<br />
and those<br />
these three properties, semi-metallic or metalloid ;<br />
with the opposite properties non-metallic.<br />
I/ustre has reference to the intensity and quality of the<br />
reflected light, considered as 'distinct from color. Several<br />
degrees in intensity have been named, (l.) Splendent,<br />
when a mineral reflects light so perfectly as to be visible at<br />
a great distance, and lively, well-defined images are formed<br />
in its faces, as galena, rock-crystal, or calc-spar. (2.)<br />
Shining, when the reflected light is weak, and only forms<br />
indistinct and cloudy images, as heavy spar. (3.) Glisten-<br />
ing, when the reflected light is so feeble as not to be observable<br />
at a greater distance than arm's length, and the-<br />
surface can no longer form an image. (4.) Glimmering,<br />
when the mineral held near the eye in full clear daylight<br />
presents only a number of small shining points, as red<br />
haematite and granular limestone. When, as in chalk, the<br />
lustre is so feeble as to be indiscernible, it is said to be dull.<br />
In regard to the kind or quality of the lustre, the follow-<br />
ing varieties are distinguished: (1.) The metallic, seen in<br />
much perfection in native metals and their compounds with<br />
sulphur, and imperfectly in glance coal. (2.) Adamantine,<br />
found in beautiful perfection in the diamond, and in some<br />
varieties of blende and carbonate of lead. (3.)<br />
Vitreous or<br />
glassy, seen in rock-crystal or common glass, or inclining
PHYSICAL PROPERTIES OP MTJTERALS. 95<br />
to adamantine in flint-glass. (4..) Resinous, when the body<br />
appears as if smeared with oil, as in pitch-stone and garnet.<br />
(5.) Pearly, like mother-of-pearl, seen in stilbite, gypsum,<br />
mica. (6.) Silky, the glimmering lustre seen on fine fibrous<br />
aggregates like amianthus.<br />
Color. This property is not in all cases of equal value<br />
as a character. Thus some minerals are naturally colored,<br />
showing<br />
in all modes of their occurrence one determinate<br />
color, which is therefore essential, and forms a characteristic<br />
of the species. This class includes the metals, pyrites,<br />
blendes, with many metallic oxides and salts. A second<br />
class of minerals are colorless, their purest forms being<br />
white, or clear like water, as ice, calc-spar, quartz, adularia,<br />
and many silicates. But these minerals are occasionally<br />
colored that is, accidentally tinged, sometimes from the<br />
chemical or mechanical admixture of some coloring sub-<br />
stance, as a metallic oxide, carbon, or particles of colored<br />
at other times from the substitution of a colored<br />
minerals ;<br />
for an uncolored isomorphous element. The colors of these<br />
minerals therefore vary indefinitely, and can never charac-<br />
terize the species, but only its varieties. Thus, quartz,<br />
calc-spar, fluor spar, gypsum, and felspar are often colored<br />
and horn-<br />
accidentally by pigments mechanically mixed ;<br />
blende, augite, garnet, and other colorless silicates, acquire<br />
green, brown, red, or black tints from the introduction of<br />
the isomorphic coloring elements.<br />
"Werner, who bestowed much attention on this portion<br />
of mineralogy, distinguished eight principal colors, white,<br />
gray, black, blue, green, yellow, red, and brown, each<br />
with several varieties or shades arising from intermixture<br />
with the other colors. He also divided them into metallic<br />
and non-metallic as follows :
96 A POPULAR TREATISE ON GEMS.<br />
METALLIC COLORS.<br />
1. White. (1.) Silver-white, as in Icucopyrite and native silver. (2.)<br />
Tin-white'; native antimony.<br />
2. .Gray. (1.) Lead-gray; galena or lead glance. (2.) Steel-gray; na-<br />
tive platina.<br />
8. Black. (1.) Iron-black; magnetite.<br />
4. Yellow. (1.) Brass-yellow; chalcopyrite. (2.) Bronze-yellow; iron<br />
pyrites. (3.) Gold-yellqw ; native gold.<br />
5. Red. (1.) Copper-red; native copper and nickeline.<br />
NON-METALLIC COLORS.<br />
1. White. (1.) Snow-white ; new-fallen snow, Carrara marble, and<br />
common quartz. (2.) Eeddish-white ; heavy spar. (3.) Yellowish-white;<br />
chalk. (4.) Grayish-white ; quartz. (5.) Greenish-white ; amianthus.<br />
(0.) Milk-white; skimmed milk, chalcedony.<br />
2. Gray. (1.) Bluish-gray; limestone. (2.) Pearl-gray; porcelain jas-<br />
per, and rarely quartz.. (3.) Smoke-gray or brownish-gray; dense smoke,<br />
dark varieties of flint. (4.) Greenish-gray; clay-slate and-whet-slate. (5.)<br />
Yellowish-gray; chalcedony. (6.) Ash-gray; wood-ashes, zoisite, zircon,<br />
and slate-clay.<br />
3. Slack. (1.) Grayish-black; basalt, Lydia'n stone, and lucullite.. (2.)<br />
Velvet-black; obsidian and schorl. (3.) Pitch-black or brownish-black;<br />
cobalt ochre, bituminous coal, and some varieties of mica. (4.) Greenish-<br />
black or raven- black; hornblende. (5.) Bluish-black; fluorspar.<br />
4. Blue. (1.) Blackish-blue; dark varieties of azurite. (2.) Azure-blue;<br />
bright varieties of azurite and lapis lazuli. (3.) Violet- blue; amethyst<br />
and fluor spar. (4.) Lavender-blue; lithomarge and porcelain jasper.<br />
(5.) Plum-blue; spinel and fluor spar. (6.) Berlin-blue; sapphire, rocksalt,<br />
cyanite. (7.) Smalt-blue ; pale-colored smalt, gypsum. (8.) Duckblue<br />
talc and corundum. ; (9.) Indigo-blue ; earthy-blue iron or vivianite.<br />
(10.) Sky-blue ; liroconite, some varieties of fluor spar and of blue spar.<br />
5. Green. (1.) Verdigris-green; amazon stone and liroconite. (2.) Cel-<br />
andine-green; green earth, Siberian and Brazilian beryl. (3.) Mountain-<br />
green; beryl, aqua-marine topaz. (4.) Leek-green; common actynolite<br />
and prase. (5.) Emerald-green; emerald, and some varieties of green<br />
malachite. (6.) Apple-green; chrysoprase. (7.) Grass-green; uranite,<br />
pmaragdite, (8.) Blackish-green; augite and precious serpentine. (9.)<br />
Pistachio-green; chrysolite and epidote. (10.) Asparagus-green; the<br />
apatite or asparagus-stone from Spain and Salzburg. (11.) Olive-green ;<br />
garnet, pitch-stone, and olivine. (12.) Oil-green; olive-oil, blende, beryl.<br />
(13.) Siskin-green; uranite, and some varieties of pyromorphite.<br />
6. Yellow. (1.) Sulphur-yellow; native sulphur. (2.) Straw-yellow;
PHYSICAL PROPERTIES OP MINERALS. 97<br />
pycnite and karpholite. (3.) "Wax-yellow; opal and wulfenite. (4.) Hon-<br />
ey-yellow; dark honey, fluor spar, and beryl. (5.) Lemon-yellow; rind<br />
of ripe lemons, orpiment. (6.) Ochre-yellow; yellow-earth and jasper.<br />
(7.) Wine-yellow ; Saxon and Brazilian topaz and fluor spar. (8.) Cream-<br />
yellow or Isabella-yellow ; bole from Strigau, and compact limestone. (9.)<br />
Orange-yellow, rind of the ripe orange, uran-ochre, and some varieties of<br />
wulfenite.<br />
7. Red. (1.) Aurora, or morning-red ; realgar. (2.) Hyacinth-red; hya-<br />
cinth or zircon, and garnet. (3.) Tile-red ; fresh-burned bricks, porcelainjasper,<br />
and heulandite. (.4.) Scarlet-red; light-red cinnabar. (5.) Blood-<br />
red; blood, pyrope. (6.) Flesh-red; felspar and barytes. (7.) Carmine-<br />
red; carmine, spinel, particularly in thin splinters. (8.) Cochineal-red;<br />
cinnabar and certain garnets. (9.) Crimson-red ; . oriental ruby and eryth-<br />
rine. (10.) Cclumbine-red ; precious garnet. (11.) Rose-red; diallogite<br />
and rose-quartz. (12.) Peach-blossom red ; blossoms of the peach, red<br />
cobalt-ochre. (13.) Cherry-red; spinel, kermes, and precious garnet.<br />
(14.) Brownish-red; reddle and columnar-clay ironstone.<br />
8. JBrotcn. (1.) Reddish- brown; brown blende from the Hartz, and<br />
zircon. (2.) Clove-brown ; the clove, rock-crystal, and axinite. (3.) Hairbrown<br />
; wood-opal and limonite. (4.) Broccoli-brown ; zircon. (5.)<br />
Chestnut-brown; Egyptian jasper. (6.) Yellowish-brown; iron flint and<br />
jasper. (7.) Pinchbeck-brown; tarnished pinchbeck, mica. (8.) Woodbrown<br />
; mountain wood and old rotten wood. (9.) Liver-brown ; boiled<br />
liver, common jasper. (10.) Blackish-brown ; mineral pitch and brown<br />
coal.<br />
The accidentally-colored minerals sometimes present two<br />
or more colors or tints, even on a single, crystal; very re-<br />
markable examples occurring in fluor spar, apatite, sapphire,<br />
This is still more com-<br />
amethyst, tourmaline, and cyanite.<br />
mon in compound minerals, on which the colors are va-<br />
riously arranged in points, streaks, clouds, veins, stripes,<br />
bands,<br />
or in brecciated and ruin-like forms. . Some miner-<br />
als again change their color from exposure to the light,<br />
the air, or damp. Sometimes merely the surface is affected<br />
or tarnished, and then appears covered as with a thin film,<br />
producing in some minerals, as silver, arsenic, bismuth, only<br />
one color ; in others, as copper pyrites, hematite, stibine,<br />
and common coal, various or iridescent hues. Occasionally<br />
the change pervades the whole mineral, the color some-<br />
V" 5
98 A POPULAR TEEATISE ON GEMS.<br />
times becoming paler, or disappearing, as in ehrysoprase<br />
and rose-quartz ; at other times darker, as in brown spar,<br />
siderite, and rhodonite. In a few minerals a complete<br />
change of color takes place, as in the chlorophaeite of the<br />
Western Isles, which, on exposure for a few hours, passes<br />
from a transparent yellow-gre'en to black. These mutations<br />
seem generally connected with some chemical change. The<br />
tarnished colors sometimes only appear on certain faces of<br />
a crystal belonging to a peculiar form. Thus a crystal of<br />
copper pyrites (like fig. 35) has one face P' free from tar-<br />
nish ; the faces b and c, close to P', are dark blue ; the re-<br />
mainder of c, first violet, and then, close to P, gold-yellow.<br />
The color of the powder formed when a mineral is scratched<br />
by a hard body<br />
is often *different from that of the solid<br />
mass. This is named the streak, and is very characteristic<br />
of many minerals. It also often shows a peculiar lustre<br />
where the mineral is soft, as in talc and steatite.<br />
Phosphorescence, Electricity, Magnetism.<br />
Phosphorescence is the property possessed by particular<br />
minerals of producing light in certain circumstances with-<br />
out combustion or ignition. Thus some minerals appear<br />
luminous when taken into the dark after being for a time<br />
exposed to the sun's rays, or even to the ordinary daylight.<br />
Many diamonds and calcined barytes exhibit this property<br />
in a remarkable degree ; less so, arragonite, calc-spar, and<br />
chalk ;<br />
and in a still inferior degree, rock-salt, fibrous gyp-<br />
sum, and fluor spar. Many minerals, including the greater<br />
part of those thus rendered -phosphorescent by the influence<br />
of the sun, also become so through heat. Thus some<br />
topazes, diamonds, and varieties of fluor spar, become luminous<br />
by the heat of the hand ; other varieties of fluor spar<br />
and the phosphorite require a temperature near that of boil-
PHYSICAL PEOPEETIES OF ]Sn> T ERALS. 99<br />
ing water; while calc-spar and many silicates are only<br />
phosphorescent at from 400 to 700 Fahr. Electricity<br />
produces it in some minerals, as in green fluor spar and<br />
calcined barytes. In others it is excited when they are<br />
struck, rubbed, split, or broken ; as many<br />
varieties of zinc-<br />
blende and dolomite when scratched with a quill, pieces of<br />
quartz when rubbed on each other, and plates of mica when<br />
suddenly separated.<br />
Friction, pressure, and heat also excite electricity in<br />
minerals. To observe this property; delicate electroscopes<br />
are required, formed of a light needle, terminating at both<br />
ends in small balls, and suspended horizontally on a steel<br />
pivot by an agate cup. Such an instrument can be nega-<br />
tively electrified by touching it with a stick of sealing-wax,<br />
excited by rubbing, or positively when the wax is only<br />
brought so n^ear as to attract the needle. When the instrument<br />
is in this state the mineral, if also rendered elec-<br />
tric by heat or friction, will attract or repel the needle ac-<br />
cording as it has acquired electricity of an opposite or<br />
similar kind ; but if the mineral is not electric, it will at-<br />
tract the needle in both conditions alike. Most precious<br />
stones become electrical from friction, and are either positive<br />
or negative according as their surface is smooth or<br />
rough. Pressure even between the fingers will excite dis-<br />
tinct positive electricity in pieces of transparent double-<br />
refracting calc-spar. Topaz, arragonite, fluor spar, carbonate<br />
of lead, quartz, and other minerals show this<br />
property.<br />
Heat or change of temperature excites electricity in many<br />
crystals, as in tourmaline, calamine, topaz, calc-spar, beryl,<br />
barytes, fluor spar, diamond, garnet, and others, which are<br />
hence said to be thermo or pyroelectric. Some acquire<br />
polar pyro-electricity, or the two electricities appear in opposite<br />
parts of the crystal, which are named, its electric
100 A POPULAR TREATISE ON GEMS.<br />
poles. Each pole is alternately positive and negative, the<br />
one when the mineral is heating, the other when it is cool-<br />
ing. The poles that become positive during an increase of<br />
temperature are named analogue ; those that become negative<br />
in the same condition, antilogue poles, as shown in this<br />
table :<br />
As already noticed, many polar electric minerals are also<br />
remarkable for their hemimorphic crystal forms. The num-<br />
ber and distribution of the poles likewise vary. In many<br />
monoaxial minerals, as tourmaline and calamine, there are<br />
only two poles, one at each end of the chief a^is ;<br />
whereas<br />
boracite has eight poles corresponding to the angles of the<br />
cube. In prehnite and- topaz, again, two antilogue poles<br />
occur on the obtuse lateral edges of the prism ooP, and<br />
one analogue pole corresponding to the macrodiagonal<br />
chief section, or in the middle of the diagonal joining the<br />
obtuse edges. The power of retaining the electricity ac-<br />
quired by rubbing, for a longer time, varies in different<br />
minerals and gems ; and as the latter are all electric, this<br />
property may sometimes be used as a distinguishing character<br />
as to the length of retaining the electricity. Abbe<br />
Haily found, in his experiments, that many precious stones<br />
lose their electric power after a few moments, whereas some<br />
will retain the same for twenty-four hours longer. The<br />
Brazilian topaz affected the needle, even after thirty-two<br />
hours.<br />
Magnetism, or the power to act on the magnetic needle,<br />
is very characteristic of the few minerals in which it occurs,<br />
chiefly ores of iron or nickel. It is either simple, attracting
PHYSICAL PROPERTIES OF MINERALS. 101<br />
both 'poles of the needle ;<br />
or polar, when one part attracts,<br />
and another repels the same pole. Some magnetic iron<br />
ores, or natural magnets, possess polar magnetism ; while<br />
the common varieties, meteoric iron, magnetic pyrites,<br />
precious garnet, and other minerals, are simply magnetic.<br />
Most minerals 'are only attracted by the magnet, but do<br />
not themselves attract iron.<br />
Smell, taste,. and. touch furnish a few characters of min-<br />
erals. Most have no smell, but some give out a peculiar<br />
odor when rubbed : as quartz, an empyreumatic- odor, or<br />
smell of burning ; fluor spar, of chlorine ; clay, of clay ;<br />
some limestones and marls, of bitumen, or a fetid odor.<br />
Aluminous minerals acquire a smell when breathed on.<br />
Other odors caused by heat, and often highly character-<br />
istic, are noticed under tests by the blo\vpipe.<br />
Taste is produced by all the salts soluble in water.<br />
Some are saline, like common salt ; sweetish astringent,<br />
like alum ; astringent like blue vitriol ; bitter, like epsom<br />
salts; cooling, like saltpetre; pungent, like sal-ammoniac;<br />
acid or sour, like sassoline, &c.<br />
alkaline, like soda ;<br />
Touch. Some minerals are distinguished by a greasy<br />
feeling, like talc ; others feel meagre, like clay others cold.<br />
;<br />
The last character readily distinguishes true gems from<br />
their imitations in glass..
102 A POPULAR TREATISE ON GEMS.<br />
CHAPTER III.<br />
CHEMICAL PROPERTIES OF MINERALS.<br />
THE consideration of the chemical nature of minerals,<br />
that is, of the elements that enter into their composition,<br />
of the manner in which these elements combine, and the<br />
variations in proportion which they may undergo without<br />
destroying the.identity of the species, forms an important<br />
branch of mineralogical science. The. methods of detect-<br />
ing the different elements, and the characters which are<br />
thus furnished for the discrimination of minerals, are also<br />
of much value. This is especially true of the metallic ores<br />
and other .substances, sought not as objects of curiosity,<br />
but for their economic qualities.<br />
Composition of Minerals.<br />
At present about sixty elements, or substances which<br />
have not been decomposed, are known. These are divided<br />
into metallic and non-metallic, a distinction of importance<br />
in mineralogy, though not always to be carried out with<br />
precision. The non-metallic elements are rarely of semimetallic<br />
aspect, and are bad conductors of heat and elec-<br />
tricity. Some are commonly gaseous oxygen, hydrogen,<br />
nitrogen, chlorine, and fluorine ; one fluid bromine ; the<br />
others solid carbon, phosphorus, 'sulphur, boron, selenium,<br />
and iodine. The metallic elements are, except mercury,<br />
solid at usual temperatures, have generally a metallic aspect,<br />
and are good conductors of heat and electricity. They are<br />
divided into light and heavy metals, the former with a
CHEMICAL PROPERTIES OF MINERALS. 103<br />
specific gravity under 5, and a great affinity for oxygen,<br />
and again distinguished as either alkali-metals, potassium<br />
(or kalium), sodium (or natrium), lithium, barium, stron-<br />
tium, and calcium ;<br />
or earth-metals, magnesium, lanthani-<br />
um, yttrium, glucinum, aluminium, zirconium, silicium.<br />
The heavy metals, with a specific gravity above 5, are<br />
divided into noble, which can be reduced or separated, from-<br />
oxygen, by heat alone ; and ignoble, whose affinity for<br />
oxygen renders them irreducible without other agents.<br />
Some of the latter are brittle and difficultly fusible, tho-<br />
rium, titanium, tantalium (columbium), tungsten (wolframium),<br />
molybdenum, vanadium, chromium, uranium, manganese,<br />
and cerium ; others are brittle and easily fusible or<br />
volatile arsenic, antimony, tellurium, and bismuth; and<br />
others malleable zinc, cadmium, tin, lead, iron, cobalt,<br />
nickel, and copper. The noble metals are, quicksilver,<br />
silver, gold, platinum, palladium, rhodium, iridium, and<br />
osmium.<br />
All the chemical combinations observed in the mineral<br />
kingdom follow the law of definite proportions; that is,<br />
two elements always combine either in the same proportion,<br />
or so that the quantity of the one is multiplied by two,<br />
three, four, or some other definite number seldom very<br />
large. As the same law prevails throughout the whole<br />
range of elements, by assuming any one, usually hydrogen<br />
or oxygen, as unity or 1, and determining froqfc experiment<br />
the simple proportion in which the others combine with it,<br />
a series of numbers is obtained which als"o expresses the<br />
proportions in which all these elements combine<br />
with each<br />
other. These numbers, therefore, mark the combining<br />
proportions or equivalents, as they are named, of the elements.<br />
They are also named atomic weights, on the sup-<br />
position that matter consists of definite atoms, and that its<br />
combinations consist of one atom (or sometimes two atoms)
104 A POPULAR TREATISE ON GEMS.<br />
of one substance, with one, two, three, or more atoms of<br />
another. This theory is not free from difficulties, but the<br />
language is often convenient. To designate the elements,<br />
chemists generally employ the first letter or letters of their<br />
Latin names. These signs also .indicate one atom or<br />
equivalent of the element. Thus, O means oxygen in the<br />
proportion of one atom ; H, hydrogen in the same proportion<br />
; N", an atom of nitrogen ; Na, an equivalent propor-<br />
tion of natrium or sodium. These signs and the equivalent<br />
weights are given in the table on next page, in one column<br />
of which hydrogen is taken as unity, in the other oxygen.<br />
Thte elements are arranged according to Berzelius, beginning<br />
with the most electro-positive, and ending with the<br />
most electro-negative.<br />
All these elements occur in minerals, but not more than<br />
twenty are common, and only about twelve abundant.<br />
They are also very rare in their simple or uncombined state ;<br />
only 'carbon in the diamond and graphite, sulphur, and<br />
about a dozen of the native metals, being thus known.<br />
More frequently minerals consist of two or more elements<br />
combined in accordance with those laws which prevail in<br />
inorganic compounds. The most important of these laws<br />
is that the combinations are binary; that is, that the ele-<br />
ments unite in pairs, which may again unite either with<br />
another compound of two, or with a single element. Inor-<br />
ganic compdtnds also are generally distinguished<br />
ganic by their greater simplicity.<br />
from or
CHEMICAL PROPERTIES OF MINERALS. 105<br />
TABLE I.<br />
Elements arranged in Electro- Chemical order.<br />
The above list includes ammonium, usually considered -a<br />
compound body, and omits the two new metals, erbium<br />
.and" terbium.<br />
The following principles are observed in designating the<br />
combinations of these elementary<br />
5-<br />
substances : For those of
106 A POPULAR TEEATISE ON GEMS.<br />
the first order the signs of the two components are conjoined,<br />
and the number of atoms or equivalents of each ex-<br />
pressed by a number following the sign like an algebraic<br />
exponent. Thus, SO, SO 2<br />
, SO3 , are the combinations of<br />
one atom sulphur with one, two, and three atoms of oxygen ;<br />
FeS, FeS 2<br />
, of one atom of iron with one or two of sulphur.<br />
But as combinations with oxygen and sulphur are very<br />
numerous in the mineral kingdom, Berzelius, to whom<br />
science is indebted for this system of signs, marks the atoms<br />
of oxygen by dots over the, sign of the other element, and<br />
those of sulphur by an accent ; the above compounds being<br />
then designated thus S, S, S, and Fe', Fe". In some cases<br />
two atoms of a base combine with three or five of oxygen<br />
or sulphur, as APO 3 Fe , 2<br />
S 3<br />
. In such cases Berzelius marks<br />
the double atom by a line drawn through the sign<br />
of the<br />
single atom ; thus, Al is two atoms aluminium with three<br />
of oxygen, or alumina ; -On, two of copper with one of oxygen,<br />
or oxide of copper. Where a number is prefixed to the<br />
sign like a coefficient in algebra, it includes both elements of<br />
the combination ; thus H is one atom water, 2 H two ; CaC<br />
is one atom carbonate of lime, 2 CaC two atoms, includ-<br />
ing, of course, two of calcium, two of carbon, and six of<br />
oxygen.<br />
The most common and important binary compounds are<br />
those with oxygen, contained in the following table, with<br />
their signs, atomic numbers, and amount of oxygen in 100<br />
parts. The more electro-negative are named acids, which<br />
are often soluble in water, and then render blue vegetable<br />
colors red. The more electro-positive are named oxides or<br />
bases, and show great affinity or attractive power for the<br />
former. The most powerful are the alkaline bases, which<br />
are colorless and soluble in water ; less powerful are the<br />
earths, also colorless, but insoluble in water :
TABLE II. Binary Compounds with Oxygen. 107
108 A POPULAR TREATISE ON GEMS.<br />
Similar to the compounds of oxygen are those with sul-<br />
phur, usually named sulphurets, and considered analogous<br />
to the oxidized bases. A few of more electro-negative<br />
character, resembling acids, have been distinguished as sulphides.<br />
Some other compounds have been named haloid<br />
gaits, and consist of certain electro-negative elements, com-<br />
bined with electro-positive ones, as bases.<br />
Many of these combinations occur as independent species<br />
in the mineral kingdom, especially those with, oxygen and<br />
sulphur. Thus the most abundant of all minerals, quartz,<br />
is an oxide, and corundum is of similar nature. Many<br />
oxides of the heavy metals, as of iron, tin, copper, and anti-<br />
mony ; and some super-oxides, as of lead and manganese<br />
(pyrolusite), are very common. Compounds with sulphur<br />
also abound, either as sulphides, with the character of<br />
acids, like realgar, orpiment, and stibine ; or as sulphurets,<br />
resembling bases, like galena, argentite, and pyrite. Less<br />
frequent are haloid salts, with chlorine and fluorine, as<br />
common salt and fluor spar; and still rarer those with<br />
iodine and bromine. On the other hand, metallic alloys,<br />
or combinations of electro-negative with electro-positive<br />
metals, are far from uncommon, especially those with<br />
arsenic, tellurium, or antimony.<br />
Combinations of these binary compounds with each other<br />
are still more common, the greater number of minerals<br />
being composed of an acid and base. By far the greater<br />
number are oxygen-salts, distinguished by giving to the<br />
acid the termination ate ; thu-s sulphate of .lead, silicate of<br />
lime, and in like manner numerous carbonates, phosphates,<br />
arseniates, aluminates. The sulphur-salts (two metals combined<br />
with sulphur, and these again combined with each<br />
other) are next in number, and perform a most important<br />
part in the mineral kingdom. The hydrates, or combinations<br />
of an oxide with water, are also common, and much
CHEMICAL PROPERTIES OF MINERALS. 109<br />
resemble the oxygen salts, the water sometimes acting as<br />
an electro-positive, at other times as an electro-negative<br />
element. Combinations of a higher order are likewise<br />
common, especially the double salts, or the union of two<br />
salts into a new body and even these ; again wr ith water,<br />
as alum and many hydrous silicates. The chemical formulas<br />
for these compound salts are formed by writing the signs<br />
of the simple salts with the sign of addition between them :<br />
thus Ca C-f-'Mg C, i. e., carbonate of lime and carbonate of<br />
magnesia, or brown spar ; Al Si 3 + K Si 3<br />
,<br />
or orthoclase ;<br />
3 Na F + Al 2 F 3<br />
,* or cryolite, composed of three compound<br />
atoms of fluorine and sodium united to one compound atom,<br />
consisting of three of fluorine and two of aluminium.<br />
Influence of the Chemical Composition on the External<br />
Characters of Minerals.<br />
That the characters of the compound must in some way<br />
or other depend on those of its component elements, seems,<br />
as a general proposition, to admit of no doubt. Hence it<br />
might be supposed possible, from a knowledge of the composition<br />
of a mineral, to draw conclusions in reference to<br />
its form and other properties; but practically this. has not<br />
yet been effected'. The distinction between the mineral-<br />
izing and mineralizable, or the forming and formed, elements,<br />
lies at the foundation .of all such inquiries. Certain<br />
elements hi a compound apparently exert more than an<br />
equal share of influence in determining its physical prop-<br />
erties. Thus the more important non-metallic elements,<br />
as oxygen, sulphur, chlorine, fluorine, are remarkable for<br />
the influence they exert on the character of the compound.<br />
The sulphurets, for example, have more similarity among<br />
themselves than the various compounds of one and the<br />
same metal with the non-metallic bodies. Still more gen-
110 A PO?ULAK TKEATISE ON GEMS.<br />
erally it would appear that the electro-negative element in<br />
the compound is the most influential, or exerts the greatest<br />
degree of active forming power. After the non-metallic<br />
elements the brittle, easily fusible metals rank next in<br />
power; then the ductile ignoble metals;<br />
then the noble<br />
metals ; then the brittle, difficultly fusible ; and last of all,<br />
the metals of the earths and alkalies.<br />
It is sometimes stated that each particular substance can<br />
crystallize only in one particular form or series of forms.<br />
This is, however, only partially true; and sulphur, for in-<br />
stance, which usually crystallizes in the rhombic system,<br />
when melted may form monoclinohedric crystals. This<br />
property is named dimorphism ; and hence the same chemical<br />
substance may form two, or even more distinct bodies<br />
or mineral species. Thus carbon in one form is the dia-<br />
mond, in another graphite ; carbonate of lime appears as<br />
calc-spar or arragonite ; the bisulphuret of iron, as pyrite<br />
and marcasite. An example of trimorphism occurs in the<br />
titanic acid, forming the three distinct species, anatase,<br />
rutile, and brookite. Even the . temperature at which a<br />
substance crystallizes -influences its forms, and so far its<br />
composition, as seen in 'an-agonite, Glauber salt, natron,<br />
and borax.<br />
Still more important is the doctrine of isomorphism, des-<br />
ignating the fact that two or more simple or compound<br />
substances crystallize in one and the same form ; or often<br />
in forms which, though not identical, yet approximate very<br />
closely. This similarity of form is generally combined with<br />
a similarity in other physical properties. Among minerals<br />
that crystallize in the tesseral form, isomorphism is of course<br />
common and perfect, there being no diversity in the dimen-<br />
sions of the primary form ; but for this very reason it is of<br />
less interest. It is of more importance among mono-axial<br />
crystals, the various series of which are separated from each
CHEMICAL PKOPERTIES OF MINERALS. Ill<br />
other by differences in the proportion of the primary form<br />
In these, perfect identity is seldom observed, but only very<br />
great similarity.<br />
The more important isomorphic substances are the fol-<br />
lowing :<br />
I. Simple substances :<br />
(l.) Fluorine and chlorine.<br />
(2.) Sulphur and selenium.<br />
(3.) Arsenic, antimony, tellurium.<br />
(4.) Cobalt, iron, nickel.<br />
(5.) Copper, silver, quicksilver, gold (?).<br />
II. Combinations with oxygen :<br />
(1.) Of the formula B.<br />
(a.) Lime, magnesia, protoxide of iron, protoxide<br />
of manganese, oxide of zinc, oxide of nickel,<br />
oxide of cobalt, potassa, soda.<br />
(b.) Lime, baryta, strontia, lead-oxide.<br />
(2.) Of the formula S.<br />
(a.) Alumina, peroxide of iron, peroxide of manganese,<br />
oxide of chromium.<br />
(b.) Antimony oxide, arsenious acid.<br />
(3.) Formula R. Tin-oxide, titanium-oxide.<br />
(4.) Formula R. Phosphoric acid, arsenic acid.<br />
(5.)<br />
Formula R.<br />
(a.) Sulphuric acid,.selenic acid, chromic acid, man-<br />
ganese acid.<br />
(b.) Tungstic acid, molybdic acid.<br />
HI. Combinations with : sulphur<br />
Formula Rf . Sulphuret of iron Fe', and sulphu-<br />
(1.)<br />
ret of zinc Zn'.<br />
(2.) Formula ft'". Sulphuret of^antimony Sb'<br />
1<br />
and<br />
',<br />
sulphuret of Arsenic As'".<br />
(3.) Formula -R'. Sulphuret of copper -0u', and sul-<br />
phuret of silver Ag'.
112 A POPULAR TREATISE ON GEMS.<br />
These substances are named vicarious, from the singular<br />
property that in chemical compounds they can mutually<br />
replace each other in indefinite proportions, and very often<br />
without producing any important change in the form or<br />
other physical properties. But there are numerous in-<br />
stances among the silicates, where the mutual replacement<br />
of the isomorphic bodies, especially when the oxides of the<br />
heavy metals come in the room of the earths and alkalies,<br />
exerts a most essential influence on the external aspect oi<br />
the species, particularly in regard to color, specific gravity,<br />
and transparency. The varieties of hornblende, augite,<br />
garnet, epidote, and many other minerals, are remarkable<br />
proofs of this influence. This intermixture *of isomorphic<br />
elements confers many valuable properties on minerals, and<br />
.to it this department of nature owes much of its variety and<br />
beauty. Without the occasional presence of the coloring<br />
substances, especially the oxides . of iron and manganese,<br />
the non-metallic combinations would have exhibited a very<br />
monotonous aspect. It is also remarkable, that in some<br />
silicates the substitution of a certain portion of the metallic<br />
oxides for the earthy bases seems to be almost a regular<br />
occurrence; while in others, as the felspars and zeolites,<br />
this rarely happens. This fact is of very great economic<br />
importance, as drawing attention to important elements<br />
often combined with others of less value. Thus iron oxide<br />
and chrome oxide, sulphuret of copper and sulphuret of<br />
silver, nickel and cobalt, may be looked for in connection.<br />
The general chemical formula for such compounds is formed<br />
by writing R (= radicle or basis) for the whole isomorphic<br />
elements; and in special instances to place their signs<br />
either one below the other, connected by a bracket, or, as<br />
is more convenient, to inclose them in brackets one after<br />
the other, separated by a comma. Thus the general sign<br />
for the is garnet R 3<br />
Si 2+R Si, which, wThen fully expressed.
CHEMICAL PROPERTIES OF MINERALS. 113<br />
;-,<br />
becomes Fe 1 1 Si'+^- [ Si; or(Ca !<br />
,Fe 3<br />
,Mn 3<br />
)Si'+(Al,e)Si,<br />
fin'}<br />
and the mineral forms many varieties, as the one or other<br />
element predominates.<br />
Chemical Reaction of Minerals.<br />
The object pf the chemical examination of minerals is<br />
the discovery of those elementary substances of which the j<br />
consist. This examination is named qualitative when the<br />
nature of the elements alone, quantitative when also their<br />
relative amount, is sought to be determined. Mineralogists<br />
are in general content with such an examination as will<br />
discover the more important elements, and which can be<br />
carried on with a simple apparatus, and small quantities of<br />
the substance investigated. The indications thus furnished<br />
of the true character of the mineral are, however, frequently<br />
of high importance. Two methods of testing minerals are<br />
employed, the one by heat chiefly applied through the blowpipe,<br />
the second by acids and other reagents in solution.<br />
Use of the Blowpipe-<br />
The blowpipe in its simplest form is merely a conical<br />
tube of brass or othei* metal, curved round at the smaller<br />
extremity, and terminating in a minute circular aperture<br />
not larger than a fine needle. Other forms have been<br />
proposed, one of the" most useful being a cone of tin, open<br />
for the application of the mouth at the smaller end, and<br />
with a brass or platina beak projecting from the side near<br />
the other or broad end. With this instrument a stream of<br />
air is conveyed from the mouth to the flame of a lamp or<br />
candle, so that this can be turned aside, concentrated, and
114 A POPULAR TREATISE ON GEMS.<br />
directed upon any small object. The flame thus acted on<br />
consists of two parts the one nearest the beak of the blow-<br />
pipe forming a blue obscure cone, the other external to this<br />
being of a shining yellow or reddish-yellow color. The<br />
blue cone consists of the inflammable gases not yet fully<br />
incandescent, and the greatest heat is just beyond its point,<br />
where this is fully effected. The blue flame still needs<br />
oxygen for its support, and consequently tends to withdraw<br />
it from any body placed within its influence, and is named<br />
the reducing flame. At the extremity of the yellow cone,<br />
on the other hand, the whole gases being consumed and<br />
the external air having free access, bodies are combined<br />
with oxygen, and this part is named the oxidating flame.<br />
Their action being so distinct, it is of great importance for<br />
the student to learn to distinguish accurately these two<br />
portions of the flame. This is best done by experimenting<br />
on a piece of metallic tin, which can only be kept pure in a<br />
good reducing flame, and acquires a white crust when acted<br />
on by the oxidating flame.<br />
The portion of the mineral to be examined should not<br />
be larger than a peppercorn, or a fine splinter a line or two<br />
long.<br />
It is supported in the flame either by a pair of fine<br />
pincers pointed with platinum, or on slips of platinum-foil,<br />
or on charcoal. Platinum is best for the siliceous minerals,<br />
whereas for metallic substances charcoal must be employed.<br />
For this purpose solid uniform pieces are chosen, and a<br />
small cavity formed in the surface in which the mineral to<br />
be tested can be deposited.<br />
In examining a mineral by heat,<br />
it should be first tested<br />
alone, and then with various reagents. When placed alone<br />
in a matrass or tube of glass closed at one end, and heated<br />
over a spirit-lamp, water or other volatile ingredients, mer-<br />
cury, arsenic, tellurium, often sulphur, may readily be de-<br />
tected, being deposited in the cooler part of the tube, or,
CHEMICAL PROPERTIES OF MINERALS. 115<br />
like fluorine, acting on the glass. It may next be tried in<br />
an open tube of glass, through which a more or less strong<br />
current of air passes according to the inclination at which<br />
the tube is held, so that volatile oxides or acids may be<br />
formed ;<br />
and in this way the chief combinations of sulphur,<br />
selenium, tellurium, and arsenic are detected. On char-<br />
coal, in the reducing flame, arsenic, and in the oxidating<br />
flame, selenium or sulphur, are shown by their peculiar<br />
odor ; antimony, zinc, lead, and bismuth leave a mark or<br />
colored ring on the charcoal ; and other oxides and sul-<br />
phurets are reduced to the pure metal. On charcoal or in<br />
the platinum pincers the fusibility of minerals is tested, and<br />
some other phenomena should be observed as whether<br />
they intumesce (bubble up), effervesce, give out fumes, become<br />
shining, or impart a color to the flame. The color is<br />
seen when the assay is heated at the point of the inner<br />
flame, and is<br />
Reddish-yellow, from soda and its'salts ; 9<br />
Violet, from potash and most of its salts ;<br />
Red, from litliia, strontia, and lime ;<br />
Green, from baryta, phosphoric acid, boracic acid, molybdic acid,<br />
copper oxide, and tellurium oxide ;.<br />
Blue, from chloride of copper, bromide of copper, selenium, arsenic,<br />
antimony, and lead.<br />
The fusibility, or ease with which a mineral is melted,<br />
should also be observed; and to render this character more<br />
precise, Yon Kobell has proposed this scale: (l.) Antimony<br />
glance, which melts readily in the mere candle flame ;<br />
(2.) Xatrolite, which in fine needles also melts in the candle<br />
flame, and in large pieces readily before the blowpipe ; (3.)<br />
Almandine (garnet from Zillerthal), which does not melt<br />
in the candle flame even in fine splinters, but in large pieces<br />
before the blowpipe ; (4.) Strahlstein (hornblende from<br />
Zillerthal) melts with some difficulty, but still more readily<br />
than (5.) Orthoclase (or adularia felspar) ; and (6.) Bron-
116 A POPULAR TREATISE ON GEMS.<br />
zite or diallage, of which only the finest fibres can be<br />
rounded by the blowpipe. In employing this scale, fine<br />
fragments of the test minerals and of that to be tried, and<br />
nearly of equal size, should be exposed at the same time to<br />
the flame. A more common mode of expressing fusibility<br />
is to state whether it is observable in large or small grains,<br />
in fine splinters, or only on sharp angles. The result or<br />
product of fusion also yields important characters, being<br />
sometimes a glass, clear, opaque, or colored ; at other times<br />
an enamel, or a mere slag.<br />
The most important reagents for testing minerals with<br />
the blowpipe are the following: (1.) Soda (the carbonate),<br />
acting as a flux for quartz and many silicates, and especially<br />
for reducing the metallic oxides. For the' latter purpose,<br />
the assay (or mineral to be tried) is reduced to powder,<br />
kneaded up with moist soda into a small ball, and placed<br />
in a cavity of the charcoal. Very often both the soda and<br />
assa^ sink into the charcoal, 'but by continuing the opera-<br />
tion they either again appear on the surface, or, when it is<br />
completed, the charcoal containing the mass is finely pounded<br />
and washed away with water, when the reduced metal is<br />
found in the bottom of the vessel. (2.) Borax (biborate of<br />
soda) serves as a flux for many minerals, which are best,<br />
fused in- small splinters on platina wire. The borax when<br />
first exposed to the flame swells up or intumesces greatly,<br />
and it should therefore be first melted into a small bead, in<br />
which the assay is placed. During the process the student<br />
should observe whether the assay melts easily or difficultly,<br />
with or without effervescence, what color it .imparts to the<br />
product both when warm and when cold, and also the effect<br />
both of the oxidating and reducing flames. (3.) Microcos-<br />
mic salt, or salt of phosphorus (phosphate of soda and am-<br />
monia), is specially important as a test for metallic oxides,<br />
which exhibit far more decided colors with it than with
CHEMICAL PROPERTIES OP MINERALS. 117<br />
borax. It is also a useful reagent for many silicates, whose<br />
silica is separated from the base and feraains undissolved<br />
in the melted salt.<br />
(4.) Solution of cobalt (nitrate<br />
of co-<br />
balt dissolved in water), or dry oxalate of cobalt, serve as<br />
tests of alumina, magnesia, and zinc oxide.<br />
In examining minerals in th*e moist way, the first point<br />
to be considered is their solubility, of which three .degrees<br />
may be noted : (!) minerals soluble in water ; (2) minerals<br />
soluble in hydrochloric or nitric acid; and (3) those un-<br />
affected by any of these fluids. The minerals soluble in<br />
water are either acids (almost only the boracic acid or sas-<br />
solin and the arsenious acid), or oxygen or haloid salts.<br />
These are easily tested, one part of the solution being em-<br />
ployed to find the electro-positive element or basis, the<br />
other the electro-negative or acid.<br />
Minerals insoluble in water may next be tested with the<br />
above acids; the nitric acid being preferable when it is<br />
probable, from the aspect of the mineral or its conduct be-<br />
fore the blowpipe, that it contains an alloy, a sulphuret,<br />
or arseniate of some metal. In this manner the carbonic,<br />
phosphoric, arsenic, and chromic acid salts, many hydrous<br />
and anhydrous silicates, many sulphurets, arseniates, and<br />
other metallic compounds, are* dissolved, so that further<br />
tests may be employed.<br />
The minerals insoluble either in water or these acids are"<br />
sulphur, graphite, cinnabar, some metallic oxides, some<br />
sulphates, and compounds with chlorine and fluorine, and<br />
especially quartz, and various silicates. For many of these<br />
no test is required, or those furnished by the blowpipe are<br />
be fused with four<br />
sufficient. The silicates and others may<br />
times their weight of anhydrous carbonate of soda when<br />
they are rendered soluble, so that further tests may be ap-<br />
plied.
118 A POPULAR TREATISE ON GEMS.<br />
Chemical Reaction of the, more Important Element*.<br />
It is not intended in this place to describe the chemical<br />
nature of the elementary substances, and still less to enu-<br />
merate the whole of those marks by which the chemist *<br />
can<br />
detect their presence. Our object is limited principally to<br />
the conduct of minerals before the blowpipe, and to a few<br />
simple tests by which their more imp'ortant constituents<br />
may be discovered by the student.<br />
I. NON-METALLIC ELEMENTS, AND THEIR COMBINATIONS<br />
WITH OXYGEN.<br />
Nitric Acid. Most of its salts detonate when heated on<br />
charcoal. In the closed tube they form nitrous acid> easily<br />
known by its orange color and smell ; a test more clearly<br />
exhibited when the salt is mixed with copper filings and<br />
treated with concentrated sulphuric acid. When to the<br />
solution of a nitrate, a fourth part of sulphuric acid, is added,<br />
and a fragment of green vitriol placed in it, the surround-<br />
ing fluid becomes of a dark-brown color.<br />
tube or on char-<br />
Sulphur and its compounds, in .the glass<br />
coal, form sulphurous acid," easily known by its smell. The<br />
minutest amount of sulphur or sulphuric acid may be detected<br />
by melting the pulverized assay with two parts soda<br />
and one part borax, and placing the bead moistened with<br />
water on a plate of clean silver, which is then stained brown<br />
or black. Solutions of sulphuric acid give with chloride of<br />
barium a heavy white precipitate, insoluble in acids.<br />
Phosphoric<br />
Acid. Most combinations with this acid<br />
tinge the blowpipe flame green, especially if previously<br />
moistened with sulphuric acid. The experiment must be<br />
performed in the dark,, when even three per cent, of the<br />
acid may be detected. If the assay is melted with six parts
CHEMICAL PROPERTIES OF MINERALS. 119<br />
of soda, digested in water, filtered, and neutralized with<br />
acetic acid, the solution forms an orange-yellow layer round<br />
a crystal of nitrate of silver. This solution, with muriate<br />
of magnesia, forms a white crystalline precipitate.<br />
Selenium and Setenic Add are readily detected by the<br />
strong smell of decayed horse-radish, and leave a gray deposit<br />
with a metallic lustre on the charcoal.<br />
Chlorine and Hs salts. When oxide of copper is melted<br />
with salt of phosphorus into a very dark-green bead, and<br />
an assay containing chlorine fused with this, the flame is<br />
tinged of a beautiful reddish-blue color,<br />
till all the chlorine<br />
is driven off. If very little chlorine is present, the assay is<br />
dissolved in nitric acid (if not soluble it must first be melted<br />
with soda on platinum wire), and the diluted solution gives,<br />
with nitrate of silver, a precipitate of chloride of silver,<br />
which is first white, but on exposure to the light becomes<br />
gradually brown, and at length black.<br />
Iodine and its salts, treated like chlorine, impart a very<br />
beautiful bright-green color to the flame ; and heated in<br />
the closed tube with sulphate of potash, yield violet-colored<br />
vapors. In solution it gives, with nitrate of silver, a pre-<br />
cipitate similar to chlorine, but which -is very difficultly<br />
soluble in ammonia. Its surest test is the blue color it im-<br />
parts to starch, best seen, by pouring concentrated sulphuric<br />
acid over the mineral in a test tube which has a<br />
piece of paper or cotton covered with moist starch over its<br />
mouth.<br />
Bromine and its salts, treated in the same manner with<br />
salt of phosphorus and oxide of copper, color the blowpipe<br />
flame greenish-blue. In the closed tube with nitrate of<br />
potassa they yield bromine vapors, known by their yellow<br />
color and peculiar disagreeable smell. Treated with "sul-<br />
phuric acid, bromine in a few hours colors starch pome-<br />
granate-yellow.
120 A POPULAR TREATISE ON GEMS.<br />
Fluorine is shown by heating the assay with sulphate of<br />
potassa, in a closed tube with a .strip of logwood-paper in<br />
the open end. The paper becomes straw-yellow, and the<br />
glass is corroded. Another test is to heat the pulverized<br />
mineral with concentrated sulphuric acid in a shallow dish<br />
of platinum (or lead), over which a plate of glass covered<br />
with a coat of wax, through which lines have, been drawn<br />
with a piece of sharp-pointed wood, is placed. If fluorine<br />
is present, the glass is etched where exposed.<br />
JBoracic Acid. The mineral alone, or moistened with<br />
sulphuric acid, when melting, colors the flame momentarily<br />
green. If the assay be heated with sulphuric acid, and<br />
alcohol added and set on fire, the flame is colored green<br />
from the vapors of the boracic acid.<br />
Carbon, pulverized and heated with saltpetre, detonates,<br />
leaving carbonate of potassa. Carbonic acid is not easily<br />
discovered with the blowpipe, but the minerals containing<br />
it effervesce in hydrochloric acid, and the colorless gas<br />
that escapes renders litmus-paper red. In solution it forms<br />
a precipitate with lime-water, which is again dissolved with<br />
effervescence in acids.<br />
Silica, before the blowpipe, alone is unchanged ; is very<br />
slowly acted on by borax, very little by salt of phosphorus,<br />
but with soda melts entirely with a brisk effervescence into<br />
a clear glass. The silicates are decomposed by<br />
salt of<br />
phosphorus, the silica being left in the bead as a powder<br />
or a skeleton. Most of them melt with soda to a trans-<br />
parent glass. .Some silicates are dissolved in hydrochloric<br />
acid, and this the more readily the more powerful the<br />
basis, the less proportion of silica, and the greater the<br />
amount of water they contain. Sometimes the acid only<br />
extracts the basis, leaving the silica as a powder or jelly ;<br />
or the silica too is dissolved, and only gelatinizes on evaporation.<br />
The insoluble silicates may be first melted with
CHEMICAL PROPERTIES OF MINERALS. 121<br />
some carbonate of an alkali*, when the solution gelatinizes,<br />
and finally leaves a dry residuum, of which the part insolu-<br />
ble in warm hydrochloric acid has all the properties of<br />
silica.<br />
n. THE ALKALIES AXD EARTHS.<br />
Ammonia, heated with soda in a closed tube, is readily<br />
known by its smell. Its salts, heated with solution of<br />
potassa, also yield the vapor, known from its smell, its<br />
action on turmeric-paper, and the white fumes that rise<br />
from a glass tube dipped in hydrochloric acid held over it.<br />
Soda, imparts a reddish-yellow<br />
color to the external<br />
flame when the assay is fused or kept at a strong red heat.<br />
In solution it yields no precipitate with chloride of platinum<br />
or sulphate of alumina.<br />
Lithia is best recognized by the beautiful carmine-red<br />
color it imparts to the flame during the fusion of a mineral<br />
containing it in considerable amount. Where the proportion<br />
is small, the color appears if the assay be mixed with<br />
1 part fluor spar and 1^ parts sulphate of potassa. In<br />
concentrated solutions it forms a precipitate with the phos-<br />
phate and carbonate of soda, but none with bichloride<br />
platinum, sulphate<br />
ol<br />
of alumina, or acetic acid.<br />
Potassa gives a violet color to the external cone,' when<br />
th^assay is heated at the extremity of the oxidating flame.<br />
The presence of lithia or soda, however, disturbs this re-<br />
.action. It may still be discovered by melting the assay in<br />
borax glass colored brown by nickel '<br />
oxide, which is<br />
changed to blue by the potassa.<br />
In concentrated solutions<br />
of potassa, the bichloride of platinum gives a citron-yellow<br />
precipitate ; acetic acid, a white granular precipitate ; and<br />
sulphate of alumina, after some time, a deposit<br />
crystals.<br />
of alum-'<br />
Baryta. The carbonate of this earth melts easily to a<br />
6
122 A POPULAR TREATISE ON GEMS.<br />
clear glass, milk-white when cold; the sulphate is very<br />
difficultly fusible. Both strongly heated at the point of<br />
the blue flame impart a green tinge to the outer flame.<br />
When combined with silica it cannot be well discovered by<br />
the blowpipe. In solution, salts of baryta yield, with sul-<br />
phuric acid or solution of sulphate of lime, immediately a<br />
fine white precipitate insoluble in acids or alkalies.<br />
Strontia, the carbonate, even in thin plates, only melts<br />
on the edges, and forms cauliflower-like projections of<br />
dazzling brightness ; the sulphate melts easily<br />
in the oxi-<br />
dating flame, and in the reducing flame is changed into<br />
sulphuret of strontium, which, dissolved in hydrochloric<br />
acid, and evaporated to dryness, gives a fine carmine-red<br />
color to the flame of alcohol. Strontia in solution gives<br />
a precipitate with sulphuric- acid, or with sulphate of lime,<br />
but not immediately.<br />
Lime. The carbonate is rendered caustic by heat, when<br />
it has alkaline properties, and readily absorbs water. The<br />
sulphate in the reducing flame changes to the sulphuret<br />
of calcium, which is also alkaline. Sulphuric acid precipi-<br />
tates lime only from very concentrated solutions; oxalic<br />
acid even from very weak ones ; and silico-hydrofluoric acid<br />
not at all. As baryta and strontia also form precipitates<br />
with the first two reagents, they must previously be sepa-<br />
rated by sulphate of potassa. Chloride of calcium tinges<br />
the flame of alcohol yellowish-red.<br />
Magnesia, alone, or as a hydrate, a carbonate, and in<br />
some other combinations, when ignited with solution of<br />
cobalt, or the oxalate of cobalt, assumes a light-red tint.<br />
It is not precipitated from a solution either by sulphuric<br />
acid, oxalic acid, or silico-hydrofluoric acid ; but phosphoric<br />
acid, with ammonia, throws down a white crystalline pre-<br />
cipitate of phosphate of ammonia and magnesia.<br />
Alumina alone is infusible. In many combinations, when
CHEMICAL PBOPERTTES OF MINERALS. 123<br />
ignited with solution of cobalt, it assumes a fine blue color.<br />
It is thrown down by potassa or soda as a white volumin-<br />
ous precipitate, which in excess of the alkali is easily and<br />
completely soluble, but is again precipitated by muriate of<br />
ammonia. Carbonate of ammonia also produces a precipi-<br />
tate which is not soluble in excess.<br />
Glucina, Yttria, Zirconia, and Thorina are not properly<br />
distinguished by blowpipe tests, though the minerals<br />
in which they occur are well marked in this way. In<br />
solution, glucina acts with potassa like alumina ; but the<br />
precipitate with carbonate of ammonia . is again soluble,<br />
with excess of the alkali, and the two earths may thus be<br />
separated. Yttria is precipitated by potassa, but is not<br />
again dissolved by excess of the alkali. With carbonate<br />
of ammonia it acts like glucina. It must be observed,<br />
however, that the substance formerly named yttria is now<br />
considered a mixture of this earth with the oxides of er-<br />
bium, terbium, and lanthanium. Zirconia acts with potassa<br />
like yttria, and with carbonate of ammonia like glucina.<br />
Concentrated sulphate of potassa throws down a double salt<br />
of zirconia and potassa, which is very little soluble in pure<br />
water.<br />
III. THE METALS.<br />
Arsenic and its sulphuret on cha/coal yield fumes, with<br />
a smell like garlic, and sublime in the closed tube. The<br />
greater number of alloys- of arsenic in the reducing flame<br />
leave a white deposit on . the<br />
charcoal ; or, where it is in<br />
larger proportion, give out grayish-white fumes with a<br />
smell of garlic. Some alloys 'also yield<br />
metallic arsenic in<br />
the closed tube. In the open tube all of them yield ar.se-<br />
nious acid, and those containing sulphur also sulphurous<br />
fumes. Many arsenic acid salts emit evident odors of<br />
and some sub-<br />
arsenic when heated on charcoal with soda ;
124 A POPULAR TREATISE ON GEMS.<br />
lime metallic arsenic when heated with pulverized charcoal<br />
in the closed tube.<br />
Antimony melts easily on charcoal, emitting dense white<br />
fumes, and leaving a ring of white crystalline oxide on the<br />
support. In the closed tube it does not sublime, but burns<br />
in the open tube with white smoke, leaving a sublimate on<br />
the glass, which is easily driven from place to place by heat.<br />
Most of its compounds, with sulphur or "with the other<br />
metals, show similar reaction. Antimony oxide on charcoal<br />
melts easily, fumes, and is reduced, coloring the flame<br />
pale greenish-blue..<br />
Bismuth melts easily, fumes, and leaves a yellow oxide<br />
on the charcoal. In the closed tube it does not sublime,<br />
and in the open tube scarcely fumes, but is surrounded by<br />
the fused oxide, dark-brown when warm, and bright-yellow<br />
when cold. Its oxides are easily reduced. A great addi-<br />
tion of water produces a white precipitate from its solution<br />
in nitric acid. .<br />
Tellurium fumes on charcoal, and becomes surrounded<br />
by a white mark with a reddish border, which, when the<br />
reducing flame is turned on it, disappears<br />
with a bluish-<br />
green light. In the closed tube tellurium gives a sublimate<br />
of the gray metal ; and in the open tube produces<br />
copious fumes, and a white powder which can be melted<br />
into small clear drops. .<br />
Mercury in all its combinations is volatile, and yields a<br />
metallic sublimate when heated alone, or with tin or soda<br />
in the closed tube.<br />
Zinc, when heated with soda on charcoal, forms a de-<br />
posit, which> when warm, is yellow; when cold, white ;<br />
tinged of a fine green by solution of cobalt, and is not further<br />
volatile in the oxidating flame. In solution, zinc is<br />
precipitated by potassa as a white gelatinous hydrate, easily<br />
redissolved in the excess of the alkali.<br />
is
CHEMICAL PROPERTIES OF MINERALS. 125<br />
Tin forms a white deposit on the charcoal behind the<br />
assay, which takes a bluish-green color with the solution oi<br />
cobalt. The oxide is easily reduced by soda.<br />
-LeadTorms a sulphur-yellow deposit with a white border<br />
on the charcoal when heated in the oxidating flame, and<br />
with soda is easily reduced. The solutions of its salts are<br />
colorless, but give a black precipitate with sulphuretted<br />
with sulphuric acid a white, and with chromate<br />
hydrogen ;<br />
of potassa a yellow, precipitate.<br />
Cadmium produces, with soda, a reddish-brown or<br />
orange-yellow ring, with iridescent border on the charcoal,<br />
and also on platinum-foil.<br />
Manganese alone, melted with borax or salt of phosphorus<br />
on the platinum wire in the oxidating flame, forms<br />
a fine amethystine glass, which becomes colorless in the<br />
reducing flame. In combination with other metals, the<br />
pulverized assay mixed with two or three times as much<br />
soda, and melted in the oxidating flame on platinum-foil,<br />
forms a bluish-green glass. Potassa or ammonia throws<br />
down from solutions of its salts a white hydrate, which, in<br />
the air, becomes gradually dark-brown.<br />
Cobalt, melted with borax in the oxidating flame, gives<br />
a beautiful blue glass. Minerals of metallic aspect must be<br />
first roasted on charcoal. The salts of protoxide of cobalt<br />
form bright-red solutions, from which potassa throws down<br />
a blue flaky hydrate, which becomes olive-green hi the air.<br />
tube and on<br />
Nickel, the assay, first roasted in the open<br />
charcoal, produces in the oxidating flame, with borax, a<br />
glass, which hot, is reddish or violet brown ; when cold,<br />
yellowish or dark red ; and by the addition of saltpetre,<br />
changes" to blue. In the reducing flame the glass appears<br />
gray. With salt of phosphorus the reaction is similar, but<br />
the glass is almost colorless when cold. The salts in solu-<br />
tion have a bright-green color, and with potassa, form a
126 A POPULAR TREATISE ON GEMS.<br />
green precipitate of liydrated nickel-oxide, which is un-<br />
changed in the air.<br />
Copper may in most cases be discovered by melting<br />
the assay (if apparently metallic, first roasted) wifh borax<br />
or salt of phosphorus in the oxidating flame, when an<br />
opaque recldish-brown glass is produced, a small addition<br />
of tin aiding in the result. In the reducing flame, the glass,<br />
when warm, is green ; when cold, blue. With soda, me-<br />
tallic copper is produced. A small proportion of copper<br />
may often be detected" by heating the assay, moistened<br />
with hydrochloric acid, in the oxidating flame, which is<br />
then tinged of a beautiful green color. Solutions of its<br />
salts are blue or green, and produce a brownisliTblack pre-<br />
cipitate, with sulphuretted hydrogen. Ammonia at first<br />
throws down a pale-green or blue precipitate, but in excess<br />
produces a very fine blue color. t<br />
Silver in the metallic state is at once known, and from<br />
many combinations can be readily<br />
extracted on charcoal<br />
with soda. From its solution in nitric acid, silver is thrown<br />
down by hydrochloric acid as a white chloride, which in<br />
the light soon becomes black, is" soluble in ammonia, and<br />
can again be precipitated from this solution by nitric acid<br />
as chloride of silver.<br />
Gold, when pure, is readily known, and is easily separated<br />
'from its combinations with tellurium on charcoal. If the<br />
and must<br />
grain is white, it contains more silver than gold,<br />
then be heated in a porcelain capsule with nitric acid, which<br />
gives it a Wack color, and gradually removes the silver, if<br />
the gold is only a fourth part or less. If the proportion of<br />
gold is greater, the nitro-chloric acid must be used, which<br />
then removes the gold. From its solution in this acid the<br />
protochloride of tin throws down a purple precipitate (pur-<br />
ple of Cassius), and the sulphate of iron, metallic gold.<br />
Platinum, and the metals usually found with it, cannot
CHEMICAL PROPERTIES OF MINERALS. 127<br />
be separated from each other by heat. Only the Osmium-<br />
iridium strongly heated in the closed tube with saltpetre<br />
is decomposed, forming osmium acid, known from its pecu-<br />
liar pungent odor. The usual mixture of platinum grains<br />
is soluble in nitro-chloric acid, leaving osmium-iridium.<br />
From this solution' the platinum is thrown down by salammonia<br />
as a double chloride of platinum and ammonium.<br />
From the solution evaporated, and again diluted, with<br />
cyanide of mercury, the palladium separates as cyanide of<br />
palladium. The rhodium may be separated by its property<br />
of combining with fused bisulphate of potassa, which is not<br />
the case with platinum or iridium.<br />
Cerium, when no iron-oxide is present, produces, with<br />
borax and salt of phosphorus, in the oxidating flame, a red<br />
or dark-yellow glass, which becomes very pale when cold,<br />
and colorless in the reducing flame. Lanthanium oxide<br />
forms a white colorless glass ; didymium, a dark amethyst-<br />
ine glass.<br />
Iron, the peroxide and hydrated peroxide, become black<br />
and magnetic before the blowpipe, and form, with borax or<br />
salt of phosphorus, in the oxidating flame, a dark-red glass,<br />
becoming bright-yellow when cold and in the ;<br />
reducing<br />
flame, especially on adding tin, an olive-green or mountaingreen<br />
glass. The peroxide colors a bead of borax contain-<br />
the protoxide produces red<br />
ing copper oxide, bluish-green ;<br />
spots. Salts of protoxide of iron form a green solution,<br />
from which potassa or ammonia throws down the protoxide<br />
as a hydrate, which is first white, then dirty-green, and<br />
finally yellowish-brown. Carbonate of lime produces no<br />
precipitate. The salts of the peroxide, on the other hand,<br />
form yellow solutions from which the peroxide is thrown<br />
down by potassa or ammonia as a flaky-brown hydrate.<br />
Carbonate of lime also causes a precipitate.<br />
Chromium forms, with borax or salt of phosphorus, a
128 A POPULAR TREATISE ON GEMS.<br />
glass, fine emerald-green when cold, though when hot often<br />
yellowish or reddish. Its solutions are usually green, and<br />
the metal is thrown down by potassa as a bluish-green hy -<br />
drate, again dissolved in excess of the alkali. The chrome<br />
in many minerals is very certainly discovered by melting<br />
the assay with three times its bulk of saltpetre, which, dis-<br />
solved in water, gives with acetate oflead a yellow precipitate.<br />
Vanadium, melted on platinum wire with borax or salt<br />
of phosphorus, gives a fine green glass<br />
in the reducing<br />
flame, which becomes yellow or brown in the oxidating<br />
flame, distinguishing it from chrome.<br />
Uranium, with salt of phosphorus, forms in the oxidating<br />
flame a clear yellow ; in the reducing flame a fine green<br />
glass. With borax its reaction is similar to that of iron.<br />
Molybdenum forms in the reducing flame, with salt of<br />
phosphorus, a green ; with borax, a brown, glass. .<br />
Tungsten or Wolfram forms, with salt of phosphorus, in<br />
the oxidating flume, a colorless or yellow, in the reducing<br />
flame, a very beautiful blue glass, which appears green<br />
when warm. AYhen accompanied by iron, the glass is bloodred,<br />
not blue. Or melt the assay with five times as much<br />
soda in a platinum spoon, dissolve it in water, filter, and<br />
decompose the result with hydrochloric acid, which throws<br />
down the tungstic acid, which is white when cold, but<br />
citron-yellow when heated.<br />
Tantalium, as tantalic acid, is readily dissolved by salt<br />
of phosphorus, and in large quantity into a colorless glass,<br />
which does not become opaque in cooling, and does not<br />
acquire a blue color from solution of cobalt. Or fuse the<br />
assay with two times as much saltpetre, and three times as<br />
much soda, in a platinum spoon ; dissolve this, filter, and<br />
decompose the fluid by hydrochloric<br />
acid :<br />
the tantalic acid<br />
separates as a white powder, which does not become yellow<br />
when heated.
CLASSIFICATION OF MINERALS. 129<br />
Titanium in anatase, rutile, brookite, and titanite, is<br />
shown by the assay forming, with salt of phosphorus, in<br />
the oxidating flame, a glass which is and remains colorless ;<br />
in the reducing flame, a glass which appears yellow when<br />
hot, and whilst cooling passes through red into a beautiful<br />
vi^fet. When iron is present, however, the glass is blood-<br />
red, but is changed to violet by adding tin. When titanate<br />
of iron is dissolved in hydrochloric acid, and the solution<br />
boiled with a little tin, it acquires a violet color from the<br />
oxide of titanium. Heated with concentrated sulphuric<br />
acid, the titanate of iron produces a blue color.<br />
CHAPTER IV.<br />
CLASSIFICATION OF MINERALS.<br />
A MINERAL species was formerly defined as a natural in-<br />
organic body, possessing a definite chemical composition<br />
and peculiar external form. The account given of these<br />
properties shows that the form of a mineral species comprehends<br />
not only the primary or fundamental figure, but<br />
all those that may be derived from it by the laws of crystallography.<br />
Irregularities of form arising from accidental<br />
causes, or that absence "of form which results from the<br />
limited space in which the mineral has been produced, do<br />
not destroy the identity of the speeies.<br />
Even amorphous<br />
masses, when the chemical composition remains unaltered,<br />
are properly classed under the same species, as the perfect<br />
crystal.<br />
The definite chemical composition of mineral species<br />
must be taken with equal latitude. Pure substances, such<br />
as they are described in works on chemistry, are very rare
130 A POPULAR TREATISE ON GEMS.<br />
in the mineral kingdom. In the most transparent quartz<br />
crystals, traces of alumina and iron oxide can be detected ;<br />
the purest spinel contains a small amount of silica, and the<br />
most ^brilliant diamond, consumed by the solar rays, leaves<br />
some ash behind. Such non-essential mixtures must be<br />
neglected, or each individual crystal would form a distiiHt<br />
mineral species. The isomorphous elements introduce a<br />
wider range of varieties, and render the limitation of species<br />
'<br />
more difficult. Carbonate of lime, for instance, becomes<br />
mixed with carbonate of magnesia or of iron in almost<br />
innumerable proportions; and the latter substances also<br />
with the former. Where these mixtures are small in amount,<br />
variable in different specimens, and do not greatly affect<br />
the form or physical characters of the predominant element,<br />
they may safely be neglected, and the mineral. reckoned to<br />
that species with which it most closely agrees. "Where,<br />
and the two substances<br />
however, the mixture is greater,<br />
are frequently found in definite chemical proportions, these<br />
compounds must be considered as distinct species, espe-<br />
cially should they also show differences in form and other<br />
external characters.<br />
Amorphous minerals with definite composition must also<br />
be considered as true species. But when they show no<br />
definite composition, as in many substances classed as clays<br />
and ochres, they cannot be accounted true mineral species,<br />
and properly ought not to be included in a treatise on<br />
mineralogy. Some of them, however, from their importance<br />
in the arts, others from other circumstances, have re-<br />
ceived distinct names and a kind of prescriptive right to a<br />
place in mineralogical works, from which they can now<br />
scarcely be banished. Many of them are properly rocks,<br />
or indefinite combinations of two or more minerals $ others<br />
are the mere products of the decomposition of such bodies.<br />
Their number is of course indefinite, and their introduction
CLASSIFICATION OF MINERALS. 131<br />
tends much to render mineralogy more complex and diffi-<br />
cult, and to destroy its scientific character.<br />
In collecting the species into higher groups, and arrang-<br />
ing them in a system, several methods have been pursued.<br />
Some, like Mobs, have looke.d only at the external charac-<br />
ters, and asserted that they alone were sufficient for all the<br />
purposes of arranging and classifying minerals. Others,<br />
led by Berzelius, foave, on the contrary, taken chemistry as<br />
the foundation of mineralogy, and classed the species by<br />
their composition, without reference to form or physical<br />
characters.<br />
Neither system can be exclusively adopted, and a nat-<br />
ural classification of minerals should take into account all<br />
their characters, and that in proportion to their relative<br />
importance. Among these the chemical, composition undoubtedly<br />
holds a high rank, as being that on which the<br />
other properties will probably be ultimately found to de-<br />
pend. Next in order is their crystalline form, especially<br />
as exhibited in cleavage ; and then their other characters<br />
of gravity, hardness, and tenacity. But the properties of<br />
minerals are as yet far from showing that subordination<br />
and co-relation which has been observed in the organic<br />
world, where the external forms and structures have a direct<br />
reference to the functions of the living being. Hence, even<br />
when all the characters are taken into account, there is not<br />
that facility in classifying the mineral that is presented by<br />
the other kingdoms of nature. Many, or rather most, of<br />
the species stand so isolated that it is scarcely possible tp<br />
find any general' principle on which to collect them into<br />
large groups, especially such groups as, like the natural<br />
families of plants and animals, present important features<br />
of general resemblance, and admit of being described by<br />
common characteristics. Certain groups of species are<br />
indeed united by such evident characters, that they are
132 A POPULAR TREATISE ON GEMS. *<br />
found together in almost every method ; but other species<br />
are not thus united, and the general order of arrangement<br />
is very uncertain. Hence, though some classifications of<br />
very considerable merit have been proposed, no natural<br />
system of minerals commanding general assent has yet<br />
appeared.<br />
The<br />
.<br />
arrangement followed in this treatise is chiefly<br />
founded on that proposed by Professor Weuss of Berlin.<br />
We have, however, made considerable changes, which the<br />
progress of the science and the more accurate knowledge<br />
of many species require. This classification appears to us<br />
to come nearer than, any other we have seen to a natural<br />
system, which in arranging and combining objects takes<br />
account of all their characters, and assigns them their place,<br />
from a due consideration of their whole nature, and is thus<br />
distinguished from artificial systems, which classify objects<br />
with reference only to one character.<br />
Besides species, two higher grades in classification seem<br />
sufficient at once to exhibit the natural relations, and to<br />
facilitate .an easy and complete review of the species com-<br />
posing the mineral kingdom. These are families and orders.<br />
In forming the families, those minerals are first selected<br />
which occupy the more important place in the composition<br />
of rocks, and consequently in the crust of the globe. Thus<br />
quartz, felspar, mica, hornblende, garnet, among siliceous<br />
minerals; calc-spar, gypsum, rock-salt, less so fluor spar<br />
and heavy spar, among% those of saline composition, stand<br />
out prominently as the natural centres or representatives of<br />
so many distinct families. To these certain metallic miner-<br />
als, as iron pyrites, lead-glance or galena, blende, magnetic<br />
iron ore, the sparry iron ore, and a few more, are readily<br />
associated as important families. But the minerals thus<br />
geologically distinguished are not sufficient to divide the<br />
whole mineral kingdom into convenient sections, and addi-
CLASSIFICATION OP MINERALS. 133<br />
tional groups must be selected from the peculiarity of their<br />
natural-historical or chemical properties. Thus the zeolites<br />
are easily seen to form such a natural group. The<br />
precious stones or gems also, notwithstanding their diverse<br />
chemical composition, must ever appear a highly natural<br />
family, when regarded as individual objects. Their great<br />
hardness, tenacity, high specific gravity without the me-<br />
.tallic aspect, their brilliant lustre, transparent purity, and<br />
vivid colors, all mark them out as a peculiar group. Only<br />
the diamond, which might naturally seem to take the chief<br />
place in this class, differs so much, not only in elementary<br />
composition, but in physical properties, that it must be<br />
assigned to a different place.<br />
Round these .species thus selected, the other Jess import-<br />
ant minerals are arranged in groups or families. It is evi-<br />
dent? that no precise definition of these families can be<br />
given, as the connection is one of resemblance in many<br />
points, not of identity in any single character. In other<br />
words, it is a classification rather according to types than<br />
from definitions, as every true natural classification must<br />
be. The same cause, however, leaves the extent of the<br />
families somewhat undefined, and also permits considerable<br />
license in the arrangement of species. But both circum-<br />
stances are rather of advantage in the present state of the<br />
science, as allowing more freedom in the grouping of spe-<br />
cies than, could be obtained in a more rigid system of clas-<br />
sification.<br />
In collecting the families into orders, the guidance ot<br />
chemistry is followed rather than of natural history, thougli<br />
the latter is also takenjnto consideration. Chemical names<br />
are assigned to the orders, but still regarded as names de-<br />
rived from the prevailing chemical characters, and not as<br />
definitions. Hence it must not be consider^! an error<br />
should two or three mineral species be found in an order
134 A POPULAR TREATISE ON GEMS.<br />
with whose name, viewed as a definition, they may not<br />
agree.<br />
Guided by these and similar considerations, minerals<br />
may be divided into the following<br />
ORDER I. THE OXIDIZED STONES.<br />
orders and families :<br />
Families. -1. Quartz. 8. Serpentine.<br />
2. Felspar. 9. Hornblende.<br />
3. Scapolite. 10. Clays.<br />
4. Haloid stones. 11. 'Garnet.<br />
5. Leucite. 12. Cyanite.<br />
6. Zeolite. 13. Gems.<br />
7. Mica. 14. Metallic stones.'<br />
ORDER II. SALINE STONES.<br />
families. 1. Calc spar. 4. Gypsum.<br />
2. Fluor spar.<br />
*<br />
5. Kock salt.<br />
3. Heavy spar.<br />
ORDER III. SALINE ORES.<br />
Families. -1. Sparry iron ores. 8. Copper salts.<br />
2. Iron salts. 4. Lead salts.<br />
ORDER IV. OXIDIZED ORES.<br />
Families. I. Iron ores. 4. Red copper ores.<br />
2. Tinstone. 5: White antimony ores.<br />
3. Manganese ores.<br />
Families. I. Iron pyrites.<br />
ORDER V. NATIVE METALS.<br />
Form only one family.<br />
ORDER VI. SULPHURETTED METALS.<br />
4. Gray copper ore.<br />
2. Galena. 5. Blende.<br />
3. Gray antimony ore. 6. Ruby-blende.<br />
ORDER VII. THE INFLAMMABLES.<br />
Families. I. Sulphur.<br />
4. Mineral resins.<br />
Diamond. 5. Combustible salts.<br />
Coal.
PART II.<br />
THE GEMS.<br />
+ *<br />
PRECIOUS STONES OK GEMS.<br />
PRECIOUS stones or gems are such minerals as, either from<br />
their beauty or other valuable properties, have become the<br />
subject of the arts or trade, and are used as ornaments, or<br />
employed by jewellers. In order to appreciate more fully<br />
such minerals as may possess superior virtue, it is our pres-<br />
ent object to consider them in reference to their scientific<br />
and practical value.<br />
DIVISION OF GEMS.<br />
Gems are generally classed as follows: 1st, real gems, or<br />
jewels ; and 2d, semi-gems, or also precious stones. The first<br />
comprise such minerals as combine, within a small space,<br />
either vivid or soft and agreeable colors, with a high de-<br />
gree of lustre, usually termed fire, as well as hardnes's;<br />
the second possess these characters in^a less degree, and<br />
occur often semi-transparent or translucent, and in larger<br />
formless masses. It is, however, impossible to draw a<br />
Gtrict line between them, as the conventional value put upon<br />
the one or the other also affects their character ; for very<br />
often some, which are generally considered as belonging<br />
to the second class, may be valued, for their peculiar prop-<br />
erties, much higher than some of the first class.
136 A POPULAR TREATISE ON GEMS.<br />
Those species of minerals which are generally considered<br />
real gems are<br />
Diamond, Garnet,<br />
Sapphire,<br />
Chiysoberyl,<br />
Spinelle,<br />
Tourmaline,<br />
Rubellite,<br />
Essonite,<br />
Emerald, Cor.dierite,<br />
Beryl, . lolite,<br />
Topaz,<br />
Quartz,<br />
Zircon, Chrysolite.<br />
The rest are considered as semi-precious stones.<br />
COLOR, GRAVITY, AND HARDNESS OF GEMS.<br />
The precious stones possess the colors in their highest<br />
perfection, and their principal and intrinsic value depends<br />
and as most gems occur in va-<br />
mostly upon this property ;<br />
rious colors, the following table will exhibit them, along<br />
with their specific gravity and hardness :<br />
LIMPID "GEMS.<br />
SPECIFIC GRAVITY. HAKDNESS.<br />
Zircon 4-41 to 470 7'5<br />
Sapphire 3-9 4-20 7-<br />
Diamond 3-5 3'6 10'<br />
Topaz (Pebble) 3-49 3-56 8-<br />
Eock Crystal (False Diamonds, Lake George,<br />
Trenton Falls) 2'69 7*<br />
Beryl, Aquamarine , 2-67 2'68 7'5<br />
BED GEMS.<br />
Zircon, Hyacinth 4-41 4-70 7'5<br />
Garnet (Oriental Garnet) 4'0 4-2 6'5<br />
Sapphire, Ruby .. 4>0 4'2 9'<br />
Garnet, Bohemian Garnet. Pyrop 3'7 3'8 6'5<br />
Spinelle, Ruby Spinelle, Ruby Balais 3'49 3*7 8-<br />
Diamond 3-5 3*6 10-<br />
Essonite 3'5 3-6 7'<br />
Topaz. "Brazilian Topaz (often burnt) 3'52 8'56 8-
GRAVITY AXD HARDNESS OF GEMS. 137<br />
SPECIFIC GRAVITY. HABDUKSS.<br />
Tourmaline, Siberite, Eubellite 3*0 to 3-30 6*5<br />
Rose Quartz. Bohemian Ruby 2'50 2*63 7'<br />
Carnelian 2'5 2'6 ?<br />
YELLOW GEMS.<br />
Zircon 4-41 4'50 7 '5 .<br />
Sapphire. Oriental Topaz ; '. . 4-0 8-<br />
Chrysoberyl 3'65 3'80 8'5<br />
Topaz. Brazilian, Saxonian, and Syrian Topaz 3'50 3'56 8'<br />
Diamond '.<br />
. . . 3-5 3-6 10*<br />
Beryl ; 2'67 2'7l 1'S<br />
Rock Crystal, Citron 2'60 2'69 7-<br />
Fire-opal 1-90 2-12 5-5<br />
GREEN GEMS.<br />
Zircon 4-41<br />
Sapphire, Oriental<br />
Chrysolite, and Emerald .. 3'9<br />
4'50<br />
4'00 V<br />
Malachite 3>6T 3-5<br />
Chrysoberyl 3'59 3'75 8'5<br />
Spinelle , 3-58 3'64 8'<br />
Diamond 3-5 3'6 10'<br />
Topaz. Aquamarine 3-49 3-56 s*<br />
Chrysolite 3'33 3'44 6'5<br />
Idocrase 3'08 3'40 6'5<br />
Tourmaline (Brazilian and Maine) 3'00 3-30 6-5<br />
Emerald..<br />
*<br />
2'67 2'73 7'5<br />
Berj'l 2-67 271 7'5<br />
Prase... 2-66 2'6S f-<br />
HeHotrope 2'61 2-63 7"<br />
Chrysoprase 2'5S 2-60 7-<br />
Felspar, Amazon Stone 2'50 2'60 6'<br />
BLUE OEMS.<br />
Sapphire 3'90 4'00 8'<br />
Disthene (Kyanite) '. . , 3'50 S'67 5'<br />
Spinelle 3'58 3'64 8'<br />
Diamond 3'5 3'6 10-<br />
Topaz. Brazilian Topaz 3-49 3'5ft S-<br />
Tourmaline, Indigolite : 3'00 3'30 6'5*<br />
Turquoise 2*86 3*00 6-<br />
Beryl, Aquamarine .* 2-67 2*71 7'5<br />
Dichroite (loUte) 2-58 2-60 7*
138 A POPULAR TREATISE ON GEMS.<br />
'<br />
SPECIFIC GRAVITY. HARDNESS,<br />
Hauyne 2-47 5'<br />
Lazulite 2-30 5-<br />
* VIOLET GEMS.<br />
Garnet 4'0 to 4-2 6'5<br />
. Sapphire, Oriental Amethyst 3 !<br />
9 4'0 9-<br />
Spinelle '. 3'58 3'64 8*<br />
Axinite 3'27 6'5<br />
Tourmaline 3'00 3'30 6'5<br />
Amethyst : 2-65 2'7S 7'<br />
BROWN GEMS.<br />
Zircon 4'41 4'50 7'5<br />
Garnet<br />
'<br />
4-00 4'20 6'5<br />
Essonite 3-53 3'60 7'<br />
Diamond 3'50 3-60 10'<br />
Toifrmaline 3'00 3-30 6*5<br />
Smoky Quartz .2-69 2*70 7'<br />
BLACK GEMS.<br />
Diamond 3-50 3'60 10*<br />
Tourmaline 3'00 3'30 6'<br />
Eock Crystal, Morion 2'69 2'7l 7'<br />
Obsidian 2-34 2'39 6"-o<br />
Pitch Coal . 1-29 1-35 2-<br />
CannelCoal : 1*23 1'27 2'<br />
GEMS DISTINGUISHED FOK THEIR VARIOUS SHADINGS OF COLOR<br />
AND LIGHT.<br />
Garnet 4-00 4'20 6-5<br />
Sapphire, Star Sapphire 3'90 4'00 9 -<br />
Chrysoberyl 3*70 3'SO 8'5<br />
Hypersthene 3'38 6-<br />
Labrador Spar 2-71 2'75 6-<br />
Dichroite 2'58 2'60 7'<br />
Cat's-eye .* 2'56 2'73 7'<br />
Adularia 2-50 2'60 6'<br />
Felspar 2'50 2'60 6-<br />
Precious Opal 2-00 2-10 5'5<br />
Hydrophane 1'90 2'00 5-<br />
A number of precious stones do not possess a local color,<br />
'
COMPOSITION OF GEMS. 139<br />
but merely a tinge or a shade of color ; and these we dis-<br />
tinguish by the following degrees of dark, high, light, and<br />
pale colored, or tinged. Another distinction may be detected<br />
in precious stones as possessing either one or more<br />
colors, or a variegated color ; or as being spotted, painted,<br />
stained with the different colors. These latter characters<br />
are, however, more proper to the semi or common precious<br />
stones, than to gems.<br />
CHEMICAL CHARACTERS.<br />
Although mineralogy could nqt exist, as a science, without<br />
the aid of chemistry, and whole systems or classifica-<br />
tions have been established, as well as the constituent parts<br />
of minerals determined, by the knowledge of Chemical char-<br />
acters, still it is difficult to resort to chemical means for distinguishing<br />
the gems or precious stones, as they would be<br />
destroyed by such an examination, and we can, for that<br />
purpose, only employ splinters or fragments. The most<br />
simple mode of proceeding is to test<br />
1st, Their greater or less fusibility, with or without a flux ;<br />
2d, Their behavior before the blowpipe, an instrument<br />
highly convenient, and, indeed, indispensable to the miner-<br />
alogist ; and,<br />
3d, The action of the acids upon them.<br />
All of these means, however, have not an effect upon all<br />
gems, as many of them, for instance, are either infusible, or<br />
fusible with the greatest difficulty by the addition of a flux.<br />
COMPOSITION OF GEMS.<br />
The attention "of writers, as far back as 1502, had been<br />
directed to the establishment of some hypothesis as to the<br />
composition .and origin of the gems, and many fabulous*<br />
views were entertained in respect to their formation.<br />
There was also connected with some hypotheses a species
140 A POPULAR TREATISE ON GEMS.<br />
of medical superstition as to their effect. Boyle (1672)<br />
formed from clear<br />
thought that all gems were originally<br />
limpid water, and that they received their color and other<br />
properties from their metallic spirit. Others considered a<br />
peculiar earth, called the noble or precious earth, as the<br />
principal ingredient of the precious stones. Bruckman<br />
(1778) recognized quartz as the principal of the gems.<br />
Bergman thought that gems were all composed of the same<br />
ingredients, such as alumina, silex, and lime, and that the<br />
different proportions produced the different species ; and<br />
the older mineralogists determined the character of the<br />
gems by their hardness, lustre, structure, and resistance to<br />
acids. But modern chemistry has ascertained the compo-<br />
nent parts, and other characters of gems, with more cer-<br />
tainty, and it is satisfactorily proved that the principles<br />
they contain are the earths, such as silica, alumina, and<br />
lime ; that some contain a peculiar earth (such is the case<br />
with the zircon, emerald, and chrysoberyl), and that the<br />
diamond, at the head of gems, consists of pure carbon,
ARTIFICIAL PRODUCTION OF GEMS/ 141<br />
Mr. Gaudin has, by means of the compound blowpipe,<br />
been able to fuse alumina and quartz, and from potassa<br />
and ammoniacal alum he has produced well-formed corundum<br />
crystals, as also crystals of ruby, of rhombohe-<br />
dral form and triple cleavage, and which, according to<br />
Malagutti, consisted of ninety-seven alumine and two silicate<br />
of lime, the exact composition of ruby. By this process<br />
the potassa originally employed was volatilized in the high<br />
temperature; this was done in 1837. Becquerel employed<br />
electricity for this purpose in its most attenuated condition,<br />
and with two or three bodies, one of which in its dry and<br />
the other in liquid state, and required from one to two<br />
years to effect its object, as the case was with a dodecahedral<br />
pentagonal crystal of iron pyrites he obtained ;<br />
sulphu-<br />
rets of copper and tin, which could not be distinguished<br />
from the native crystals. He has even obtained crystals of<br />
oxide of zinc, which- were octahedral, transparent, refract-<br />
ing strongly the light, and hard enough to scratch glass,<br />
and altogether unknown in the mineral kingdom. His<br />
process was, on a silicate of potassa solution to let act-<br />
slowly a voltaic current from a sheet of zinc, around which<br />
a copper wire was wound. The density of the liquid was<br />
22 areometer; water was thereby decomposed with dis-<br />
engagement of hydrogen gas<br />
and formation of oxide of<br />
zinc, which was dissolved again, and after a fortnight, very<br />
fine brilliant crystals were visible on the zinc plate, which,<br />
after a lapse of two years, were the size of a millimeter.<br />
Mr. Ebelman conceived the idea of obtaining artificial^<br />
crystals from infusible silicates and aluminates, by replac-<br />
ing the water contained in many metallic oxides in higli<br />
temperatures with boracic acid, borate of soda, phosphorus,<br />
and alkaline phosphates, and its final evaporation in high<br />
temperatures. He prepared certain oxides, calculating<br />
the proportions, such as alumina and silica, and exposed
142 'A POPULAR TREATISE ON GEMS.<br />
them in a platina capsule, at a high temperature, in his<br />
porcelain furnace of the Sevres manufactory, of which he<br />
was the director, and with the mixture of boracic acid kept<br />
the mass in a fusion, and the corundum and crystallized<br />
silex were the results. He used boracic acid for this purpose,<br />
as he found it more convenient than the other, dissolvents.<br />
Mr. Ebelman has fused together, in order to obtain the<br />
spinelle (which is composed of. 72 parts of alumina and 28<br />
parts magnesia),<br />
Alumina,<br />
Magnesia,<br />
Fused boracic acid,<br />
- - G grammes.<br />
- -. 3<br />
Green oxide of chrome, O'1-O to 0*15 grammes.<br />
The latter was added for the purpose of rendering the mass<br />
of a rose color. This mixture, put into an uncovered pla-<br />
tina capsule, was exposed to the heat of the porcelain fur<br />
nace ; after the baking was finished, the melted mass formed<br />
a rose-colored layer on the bottom of the capsule, and in<br />
the mass octahedral crystals of spinelle, quite identical with<br />
the natural crystals of the ruby spinelle, were taken out,<br />
which were exceedingly Brilliant. The author received in<br />
1851, while on a visit to Paris, from Mr. Ebelman, about<br />
thirty of those crystals, weighing about one grain, and<br />
which he submitted, on his return to the United States, to<br />
numerous chemical and mineralogical tests, both as to<br />
hardness, specific gravity, and lustre, and was extremely<br />
gratified as to its results.<br />
Mr. Ebelman manufactured the blue spinelle, by substi-<br />
tuting the same quantity of oxide of cobalt for the oxide of<br />
chrome; also by substituting the oxide of zinc for .the<br />
magnesia, he obtained the garnet, which he prepared by<br />
- 6<br />
Alumina,<br />
Oxide of zinc,<br />
Fused boracic acid, 6<br />
"<br />
" .<br />
- 6 grammes.<br />
- 5 * "<br />
"
ARTIFICIAL PRODUCTION OF GEMS. 143<br />
The mass was brought slowly to a white-heat temperature,<br />
and kept from twenty-four to thirty hours in that condition.<br />
The boracic acid begins to evaporate during the last five<br />
hours.<br />
The emerald was obtained artificially by a mixture of<br />
Silex,<br />
Alumina,<br />
- -4 grammes.<br />
- T60 "<br />
Glucia, - - 1-40<br />
Fused boracic acid; 4*06<br />
Oxide chrome,<br />
"<br />
"<br />
- O'lO "<br />
Mr. Daubree has produced artificially the oxide of tin,<br />
by passing through a heated porcelain tube two currents<br />
of the vapors of the perchloride of tin and water, by which<br />
a double decomposition was effected, so that in the interior<br />
of the porcelain tube small crystals of oxide of tin were de-<br />
posited, arid hydrochloric acid gas passed off in the form of<br />
vapor. The crystals of tin- were deposited at the orifice of<br />
the porcelain tube, where the temperature was scarcely<br />
300, while no crystals were deposited in the hottest part ;<br />
the crystals of tin scratched glass easily, were infusible,<br />
and were, not affected by acids, and had a specific gravity<br />
of 6-72.<br />
The latest discoveries of Mr. Daubree have .brought to<br />
light many important facts in regard to the formation of<br />
rocks which contain crystalline substances, differing widely<br />
in their fusibility. By the action of chloride of silicium at<br />
red heat, and vapor on many bases which enter into various<br />
rocks he obtains in exchange, by decomposition, chlorine<br />
bases and free silica (silicic acid), which appears as quartz<br />
in crystals ; if he desires an action of the chloride of sili-<br />
cium on chalk, magnesia, alumina, or glucia, he obtains<br />
crystals of quartz, wallastonite, peridote, and -disthene ;<br />
the purpose of obtaining double silicates, he not only adds<br />
the bases for silicifying in proper proportions, but also in<br />
for
144 A POPULAll TKEATISE ON GEMS.<br />
excess sufficient oxygen for forming silicic acid. A mixture<br />
of chalk or magnesia, for instance, to the chloride of sili-<br />
cium, produced crystals of diopside, perfectly colorless,<br />
with a characteristic slope of this mineral. He also ob-<br />
tained crystallized felspar by the mixture of 1 equivalent<br />
of alkali (potassa and soda), 1 equivalent of alumina, with<br />
6 equivalents of lime under the influence of chloride of si-<br />
licium. Similar mixtures have produced crystals of garnet,<br />
idocrase, phenakite, emerald, euclase, zircon, and wilhelm-"<br />
ite. He also produced tourmaline in regular hexagonal<br />
prisms, which were grouped upon quartz crystals just as<br />
they are often observed in crystalline rocks of shorl. By<br />
the same method, but replacing the chloride of aluminum<br />
for action upon the bases, he obtained corundum crystals,<br />
the contact of<br />
spinelle crystals, and garnet crystals ; by<br />
perchloride<br />
of iron with chloride of zinc he obtained fine<br />
crystals of franklinite ; crystals of magnesia or periclase,<br />
like those from Mount Somma, were produced by the<br />
action of lime on chloride of magnesium, but remarkable<br />
enough, their production is just the counterpart of the ori-<br />
gin of the native mineral, where constantly chlorine vapors<br />
are disengaged, and where it detaches itself from the dolo-<br />
mite geodes.<br />
Mr. Durocher obtained, by the action of sulphuretted<br />
hydrogen gas upon the chlorides of iron and zinc, crystals<br />
of magnetic pyrites and blende ; he also obtained, by the<br />
action of different vapors, sulphurets of antimony and<br />
arsenic, and the gray antimonial copper.<br />
Mr. Senarmont obtains quartz crystals in perfect hexagonal<br />
prisms, with all the other specific characters, from the<br />
gelatinized silica, under a high temperature and the high<br />
pressure of thirty atmospheres.<br />
The artificial production of the diamond has been latterlyeffected<br />
by the ingenious contrivance of Despretz, which
GEOLOGICAL CHARACTERS. 145<br />
consists in passing an electric current "into an exhausted<br />
bottle, in the lower part of which is placed a small cylinder<br />
of charcoal, and from the upper part "are suspended pla<br />
tina wires or platiua foils; the sparks thereby obtained<br />
from the combustion of the charcoal are of a reddish-violet<br />
color ;<br />
after the lapse-of one month, during which the com-<br />
bustion continues, a little black layer of charcoal is depos<br />
ited upon the platina ;<br />
under the microscope they appear<br />
like very small octahedrons, quife analogous to the diamond<br />
some were free from ;<br />
color, and very brilliant.<br />
GEOLOGICAL CHARACTERS.<br />
The origin, locality, and geological characters of gems<br />
it was formerly supposed that the trap forma-<br />
are various ;<br />
tion was their matrix ; but it is ascertained that we find<br />
them distributed in rocks of different ages and kinds, either<br />
as accidental mixtures such as garnet in gneiss and mica-<br />
ceous schiste or in drusy cavities, such as the emerald,<br />
which occurs in druses of argillaceous slate and micaceous<br />
schiste ; and many precious stones are found- in gangues.<br />
Many gems are found at a distance from their original bed,<br />
on secondary or diluvial strata, or &i the beds of rivers,<br />
mixed with their sand. Thus, zircon is found in Ceylon in<br />
regular beds ; and likewise we find in Ceylon, after much<br />
rain, the topaz, zircon, and other gems. This happens<br />
more frequently in the beds of the rivers, and then the<br />
gems appear often in the shape of pebbles, showing that<br />
those hard stones, carried away from their original beds,<br />
have been rolled and rounded by the streams and rivers,<br />
although they retain sometimes their crystalline structure,<br />
on account of their hardness.<br />
The discovery of diamonds in Russia, far from the tropi-<br />
cal region, has excited "much interest among geologists.<br />
7
146 A POPULAR TREATISE ON GEMS.<br />
In the detritus on the banks of the Adolfskoi, no fewer<br />
than forty diamonds have been found in the gold alluvium,<br />
only twenty feet above the stratum in which the remains<br />
of mammoths and rhinoceroses are found. Hence Hum-<br />
boldt has concluded that the formation of gold-veins, and<br />
consequently of diamonds, is comparatively of recent date,<br />
and scarcely anterior to the destruction of the mammoths.<br />
Sir Roderick Murchison and M. Yerneuil have been led to<br />
the same result by different arguments.<br />
GEOGRAPHICAL DISTRIBUTION.<br />
The locality of gems bears some highly interesting<br />
characters, inasmuch as we may sometimes judge, from<br />
. their appearance, the climate of their locality ; and it<br />
seems as if the countries ofthe torrid zone had been par-<br />
ticularly favored by nature in producing the most precious<br />
gems, or that those hot-beds were more propitious to the<br />
formation of the blossoms of the inorganic world. Com-<br />
paring, for instance, spinelles and zircons, from Siberia,<br />
with those of Ceylon and Peru, we find the first to be dark<br />
and of an impure color, as if emblematic of a cold, un-<br />
friendly, northern climate ;<br />
whereas the latter glitter with<br />
full brilliancy, and possess all those properties and beauties<br />
for which gems are so highly esteemed. Often, too, we<br />
find the gems collected in particular countries, or isolated<br />
spots of our globe, such as the most precious gems from<br />
the East Indies and Brazil, where, singular enough, they<br />
occur with the precious metals ; as, for instance, the diamond<br />
in company with gold and platina in Brazil. Some<br />
of the gems have likewise been hitherto discovered in a<br />
single spot on one continent only, and are then exhausted*;<br />
'<br />
such as the rubellite, in Maine, United States the iolite in<br />
;<br />
Connecticut, United States, and the lazulite in Persia.
NOMENCLATIVE OF GEMS. 147<br />
PRACTICAL DIVISION AND NOMENCLATURE OF GEMS. -<br />
Artists have not profited, in their arrangement and no-<br />
menclature of gems, by the advanced state of mineralogy,<br />
and although they have been newly classified<br />
as a science ;<br />
by mineralogists according to their scientific characters,<br />
the practical artist arranges them according to those properties<br />
that principally attract the eye : such as color, trans-<br />
parency, and lustre. Gems have, in consequence, received<br />
their names from their color : as ruby, from its red color ;<br />
sardonyx, yellow onyx. Gems of different species, but of<br />
the same color, are often named from their color. For<br />
instance, the corundum, the spinelle, or the topaz, if of a red<br />
color, is called ruby ; if blue, sapphire ; if green, emerald ;<br />
if yellow, topaz, and if violet, amethyst : and thus gems of<br />
the same color, but of different composition, are arranged<br />
under the same head. The artist confounds under the<br />
name of Brazilian ruby, either a light rose-red spinelle,<br />
or a topaz approaching to the red color. The name of a<br />
country or locality, is often sufficient to give a name to gems<br />
of the same color, but of different shadings, and of more<br />
or less vivid lustre. Thus, by Oriental chrysolite is meant<br />
a yellowish-green sapphire, and by Saxonian chrysolite, a<br />
pale wine-yellow topaz. Many gems have always been<br />
known under the name of Oriental gems, partly because<br />
they were first obtained in the East, and partly because<br />
they stood, from their excellent properties, in higher estimation<br />
than those from an^ other country. Those from<br />
the East were likewise callecf " Oriental," in opposition tQ<br />
others less valuable, which were called " occidental" gems.<br />
Subsequently, all gems of superior qualities were called<br />
Oriental gems, even when their locality was not in the<br />
East. Thus, for instance, that precious opal, so well distinguished<br />
for its beautiful play of colors, is called the On-
148 A PQPUIAR TREATISE ON GEMS.<br />
ental opal, although it is never found there ; likewise, the<br />
purest and most valuable emerald, which in great perfection<br />
only occurs in Peru, is known as the Oriental emerald.<br />
HISTORY OF GEMS.<br />
Those precious stones, which are now called gems, were<br />
known in ancient times but very little, if at all. The first<br />
notice given of them is in the Bible, where it is stated that<br />
the high priest wore one stone on his gold scarf, and twelve<br />
gems set in gold plate, called the Urim and Thummim,<br />
each of which represented a tribe. It appears that the<br />
Hebrews borrowed the names of their gems from the<br />
Egyptians, and few of the gems with the exception of<br />
the sapphire named in the holy Scriptures correspond in<br />
any respect with those at present known in our mineralogical<br />
books. The Greeks appear to have been but little ac-<br />
quainted with gems, as they did not use them as ornaments<br />
in the Trojan wars; and Homer, when speaking of the<br />
treasures of those tunes, does not make any mention of<br />
gems. Theophrastus and Pliny have described some gems<br />
of their time very imperfectly and confusedly ; and their<br />
descriptions are so replete with vain fancies, that it is diffi-<br />
cult to identify any from their descriptions. They attributed<br />
most wonderful powers to gems ; gave fabulous descriptions,<br />
and the most singular and perverted views in regard to<br />
their origin ;<br />
and it was said that they had great influence<br />
upon health and beauty, riches, honor, and good fortune.<br />
They were called, when worn,*amulets. They were brought<br />
into connection with the planets, the twelve constellations,<br />
and the seasons of the year ; and a certain gem was worn<br />
each month, which was said to have during the term, its pe-<br />
culiar influence and healing virtues. Such superstitious<br />
notions have been transmitted to our times. The gems cor-
HISTORY O? GEMS. 14p<br />
responding to the different months, and also to the twelve<br />
Jewish tribes, are the following :<br />
January Hyacinth "Dan.<br />
February Amethyst Gad.<br />
March Jasper Benjamin.<br />
April Sapphire Issaehar.<br />
May Agate Naphtali.<br />
June Emerald Levi.<br />
July Onyx Zebulon.<br />
August Carnelian .. Reuben.<br />
September Chrysolite Asher.<br />
October Beryl Joseph.<br />
November Topaz ". Simeon.<br />
December Ruby Judah.<br />
Artists have made certain changes in some of the gems<br />
corresponding to the months, and the tribes represented<br />
in the Urim and Thummim ; they consider May to be repre-<br />
sented by emerald :<br />
June by Chalcedony, Onyx, or Agate ;<br />
July<br />
CarneliarT ;<br />
August Sardonyx ;<br />
October Aquamarine ;<br />
December Chrysoprase, Turquoise, or Malachite.<br />
In the early ages similar views were entertained in the<br />
East, and many of them are yet prevalent. The Persians<br />
believe that spinelle affords joy, and 'protects them against<br />
bad dreams. The Indians believe in the efficacy of large<br />
diamonds to bring them back to their families. (The Rajah<br />
of Mattan, a district of Western Borneo, possessed a. diamond<br />
of 367 carats.) The ruby is esteemed, in the East,<br />
as a talisman, Avhich is never shown willingly to friends ;<br />
it is considered ominous if it contains any black spots. The<br />
Chinese, on the contrary, present the same stone as a testimony<br />
of friendship. The Peruvians adore the emerald as
150 A POPULAR TREATISE ON GEMS.<br />
their deity. Many of these fabulous notions were probably<br />
brought from the East to Europe; for we find, in the<br />
middle ages, similar views entertained by Marbodus, Bishop<br />
of Rennes, who wrote a book on the miraculous powers of<br />
gems. The twelve Apostles were likewise represented<br />
symbolically by gems, and they were called " the Apostle<br />
gems;" as<br />
Jasper for St. Peter ;<br />
*<br />
St. Andrew ;<br />
Sapphire<br />
Chalcedony<br />
St. James ;<br />
Emerald St. John ;<br />
Sardonyx<br />
St. Philip;<br />
Carnelian St. Bartholomew ;<br />
Chrysolite ; St. Matthew ;<br />
Beryl St. Thomas ; ^<br />
Chrysoprase.. St. Thaddeus ;<br />
Topaz<br />
St. James the Less ;<br />
Hyacinth<br />
St. Simeon ;<br />
Amethyst St. Matthias.<br />
The ancients, induced by the beauty of gems the pure<br />
and deep color of the emerald, the vivid and high lustre<br />
of the diamond, and the agreeable reflections of the opal<br />
had commenced using them as ornaments and jewelry,<br />
and they took pains to adapt them to their purposes.<br />
Although they did not, in 'those times, understand the art<br />
of cutting and polishing them as practised at the present<br />
time, yet they endeavored to work them into all possible<br />
shapes, by rubbing off the corners, or polishing the natural<br />
faces. They generally fixed the gems on strings ; they<br />
also tried to carve figures representing deities, religious<br />
costumes, historical events, exploits of celebrated generals,<br />
or the heads of great men.
SCULPTURE IN GEMS. 151<br />
SCULPTURE IN GEMS.<br />
The art of carving was well known to the ancients, and<br />
those stones were called gems, in the proper sense of the<br />
word, which had figures or letters engraved on them in a<br />
very small compass, the workmanship of which we, at this<br />
day, cannot help admiring.<br />
is the<br />
Gem-sculpture, or the glyptic art (or lithoglyptics),<br />
art of representing designs upon precious stones, either in<br />
raised work (cameos) or by figures cut into or below the<br />
surface (intaglios). The first were most natural to the<br />
rising art, and were used as seals ;<br />
whereas the latter were<br />
used as ornaments, for which the most precious materials<br />
were employed, according to the state .of the art. They<br />
did not understand engraving on diamonds, or many<br />
other gems : they employed only the softer stones, the<br />
common precious stones, such as earn eh* an, onyx, jasper,<br />
&c. ; they also used paste, or artificial colored glass composition,<br />
for their engravings. Their mode of working was<br />
very simple :' the polishers prepared then* stones on a plate,<br />
by means of the powder of harder stones, either round,<br />
oval, flat, or in shield form, according to the designed sub-<br />
ject, and then left to the sculptors the subject of the engraving,<br />
which was done by means of iron, or diamond<br />
splinters mounted in iron. It was not until the year 1500<br />
that Ambrosius Caradossa first discovered the method of<br />
cutting the diamond. He prepared the figure of a patriarch<br />
for Pope Julian n. He also discovered the first traces of<br />
sculpture among the Jews, Persians, and Egyptians. In<br />
the traditions of the holy Scriptures, Moses, for instance,<br />
had the names of the twelve tribes of Israel engraved on<br />
the gems used by the high-priest. Solomon possessed a<br />
seal : Alexander presented his seal to Perdicas. Augustus<br />
had a sphinx engraved on his seal ; but the Indians and
152 A POPULAK TREATISE ON GEMS.<br />
Persians engraved mostly mythological animals or priests<br />
in their gems the ; Egyptians, beetles, which they adored,<br />
and which are called the<br />
"<br />
scarabsei. Abraxes" were the<br />
oldest gems, which had the representation of fantastical<br />
animals, with the above word in<br />
graved on them.<br />
the Greek language, en-<br />
The Phenicians, Hetrurians, and Greeks learned the<br />
and from them it was<br />
art of carving from the Egyptians ;<br />
carried to the Romans, where it was lost, in the decline<br />
of the empire, in the fifteenth century, under the Popes<br />
Martin V. and Paul II. The art was revived again by<br />
some fugitive Greeks in Italy. Great merit is also due to<br />
the Medicians for the revival of the art ; and Giovani was<br />
considered the first in Italy. The talisman, or carved<br />
gems bearing Arabian letters, belong to those times.<br />
Precious stones with layers and veins, or such as onyx, sar-<br />
donyx, &c., were employed by the ancients, with great<br />
skill, in the carving of cameos, where we find the head of<br />
one color, and the hair and dress of a different color carved<br />
out of the other layer of the stone. Very often the sub-<br />
jects were mythological, and this mode of carving or sculpture<br />
has been imitated by modern artists. It is sometimes<br />
with difficulty that Ave are enabled to distinguish the an-<br />
cient from the modern works, and the only authentic<br />
authority for the antiquity of the cameo or intaglio is its<br />
excavation from ancient monuments, except in a few in-<br />
stances, where we may be able to judge by comparison of<br />
the difference in antiquity ; by observing whether or not<br />
they, are unnaturally, or stiffly done;. have large heads,<br />
hands, and feet, or stiff streaks resembling the hair, &c.<br />
We find that some gods, representing the peculiar gems<br />
(such we see all sculptures of Bacchus, and what relates to<br />
him), were executed in amethyst, being the color of wine ;<br />
and all nymphs, Neptune, or fish, in aquamarine,
ON GRINDING. 153<br />
color of water. We find also, in Germany, traces of sculpture<br />
in the fourteenth and sixteenth centuries ; the oldest<br />
known artist, Daniel Engelhard, at Kuremburgh, died in<br />
1552 ; also Lucas Kilian; and the best artist, Nater, died<br />
in 1705. England and France had likewise very distinguished<br />
artists in carving. A full history of gem-sculpture<br />
may be found in the Encyclopedia Americana, pp. 403-405.<br />
ON GRINDING.<br />
The art of grinding gems is of more modem origin; it<br />
consists in cutting the gems, and other precious stones, into<br />
figures, bounded by many planes, and by polishing the<br />
faces thus formed, increasing their lustre, transparency, and<br />
other valuable properties. This constitutes the work of<br />
the lapidary. In the year 1290 a society of lapidaries was<br />
formed at Paris, and in 1385 there were diamond-cutters at<br />
Nuremburgh ;<br />
but it Avas not until 1456 that Ludwig Yan<br />
the diamond with its<br />
Bergen invented the art of polishing<br />
own powder; gems were then cut according to mathematical<br />
principles; the art has been brought, in modern<br />
tunes, to the greatest perfection. There is a great difference<br />
in gems (which are mostly procured from the Indies in a<br />
rough or polished state), easily to be detected by their im-<br />
Fig. 1. Fig. 1 a.
154 A POPULAR TREATISE OX GEMS.<br />
perfections. The Indians look more upon the size of the stone<br />
than upon the cut, which is generally irregular and devoid<br />
of symmetry. We observe this in the two celebrated diamonds<br />
of the Shah of Persia, the Dariainur brilliant sea<br />
(figs. 1 and 1 a), and the Kuinur brilliant mountain<br />
(figs. 2 and 2 a)", the one is worn on the left arm, and the<br />
other on the right knee.<br />
/<br />
Fig. 2.<br />
Fig. 2 a.<br />
By looking at the subjoined representation<br />
of the dia-<br />
mond belonging to the crown of France (figs. 3 and 3 ),<br />
which weighs one hundred and thirty-six and a quarter<br />
carats, is fourteen lines long, thirteen and a quarter lines,<br />
broad, and nine and a quarter lines thick, and which is<br />
known by the name of liegent, we can more distinctly dis-<br />
criminate the irregular and unmathematical cut.<br />
The gem-grinders are divided into three classes: first,
OX GELSTDING. 155<br />
Fig. a .<br />
^<br />
Fig. So.<br />
the diamond ; second, the gem ; and third, the jewelry<br />
grinders.<br />
The diamond grinder divides his work into
156 A POPULAR TREATISE ON GEMS.<br />
furrow is obtained, which will render the planes suitable<br />
for applying the cleaving instrument, and this operation is<br />
repeated with every plane.<br />
Diamonds that are not fit for<br />
being cloven, are called by the Dutch, " divelsteene" (devilstones).<br />
Large diamonds, which are too precious to be<br />
expose to a dangerous cleavage, are sawed by means of a<br />
fine steel wire, moistened with oil and diamond-powder.<br />
The rough-cut diamonds, as they are brought from the<br />
Indies, are called laborer.<br />
Mr. Mawe gives the following description of the art of<br />
diamonds :<br />
cutting -and polishing<br />
" The object of cutting and polishing the diamond is<br />
twofold :<br />
" First, to divide the natural surface of the stone in a<br />
symmetrical manner, by means of a number of highlypolished<br />
polygonal planes, and thus to bring out to the<br />
best advantage the wonderful refulgence of this beautiful<br />
gem ; and, secondly, by cutting out such flaws as may<br />
happen to be near the surface, to remove those blemishes<br />
that materially detract from its beauty, and consequently<br />
from its value.<br />
" The removal of flaws is a matter of great importance:<br />
for, owing to the form in which the diamond is cut, and its<br />
high degree of refrangibility, the smallest fault is magnified,<br />
and becomes obtrusively visible in every facet. For this<br />
reason, also, it is by no means an easy matter, at all times,<br />
to ascertain whether a flaw is" or is not superficial ; and a<br />
person with a correct and well-practised eye may often purchase,<br />
to great advantage, stones which appear to be flawed<br />
quite through, but are, in fact, only superficially blemished.<br />
"The first thing the artist has to do, when a rough diamond<br />
is put into his hands, is to examine carefully in what<br />
direction the stone may be cut, so as to afford the greatest<br />
breadth, or spread, as it is technically termed, after the<br />
'
ON GRINDING. 157<br />
a stress<br />
flaws, if any, shall have been taken out. f So great<br />
is laid, by modern fashion, on the superficial extent of a<br />
brilliant, that the old rules of proportioning its dimensions<br />
are now nearly obsolete: the best cutters have entirely<br />
discarded the use of measures, and, in forming the facets,<br />
trust wholly to an accurate and well-practised eye. The<br />
direction being determined on, the artist must he well<br />
aware which are the hard points and which the soft ones ;<br />
the former being those solid angles of the original octahe-<br />
dron, which it is necessary to cut directly across, and the<br />
latter those solid angles which are to be obliquely divided.<br />
A degree of force which may be safely applied, and is even<br />
requisite in making a section through the former, will be<br />
very apt to flaw and tear up the laminaB when applied to<br />
latter. On these accounts it probably is, that the fatiguing<br />
and even painful process of performing this part of the<br />
business by hand, is not yet superseded by<br />
the use of<br />
machinery.<br />
" These preliminary matters being settled, the diamond<br />
is imbedded in^a strong cement, fixed at the end of a stout<br />
spindle-shaped stick, about a foot long, with that portion<br />
only projecting, the removal of which is to form the first<br />
facet. The instrument employed for this purpose is another<br />
diamond, fixed in a stick similar to the former, with one of<br />
the solid angles projecting. In order to collect the powder<br />
and shivers that are detached during the process, the cut-<br />
ting is performed over a strong box, four or five inches<br />
square, furnished with a false bottom perforated with ex<br />
cessively minute holes, in order to sift, as it were, the dust<br />
from the shivers; and also with two upright iron pegs,<br />
fixed on the sides, for the workman to support and steady<br />
his fingers against, while with a short repeated stroke,<br />
somewhat between scratching and cutting, he is. splitting<br />
off, or more laboriously wearing away the diamond in that
158 A POPULAR TREATISE ON GEMS.<br />
part where the facet is to be placed. This being done, the<br />
cement is softened by warming it, and the position of the<br />
diamond is changed, in order to bring a fresh part under<br />
the action of the cutting-diamond. When,<br />
in this slow<br />
laborious way, all the facets have been placed upon the sur-<br />
face of the diamond, the cutting is completed. The stone,<br />
if examined by a moderate magnifier, now presents ragged,<br />
rough edges; and a broken, foliated surface, with a glistening<br />
lustre on those facets that are' nearly in the direction<br />
of the natural lamina?, and on the other facets a more even<br />
surface, but of a dull opaque grayish-white color.<br />
" The shape of many diamonds is so irregular, that it is<br />
necessary to remove pieces of considerable magnitude in<br />
order to bring them to a form proper for cutting. Where<br />
the lines of these proposed sections coincide with the<br />
natural lamellar structure of the stone, the workman has<br />
recourse to the delicate, and perhaps somewhat hazardous,<br />
operation of splitting the diamond, by which a double ad-<br />
vantage is obtained. In the first place, there is a great<br />
the slices or shivers<br />
saving of time ; and in the second place,<br />
are themselves sufficiently large to admit of being cut and<br />
polished. The method of splitting is made a great mystery ;<br />
thus much, however, may be mentioned, that when the<br />
direction in which ^the section is to be made has been deter-<br />
mined on, it is marked by a very fine line, cut by the<br />
of another dfamond : the- stone is afterwards fixed<br />
point<br />
by strong cement in the proper position, in a block of wood,<br />
and then, by the application of a due degree of force, the<br />
section is effected.<br />
"<br />
The diamond being thus, by the joint action of splitting<br />
and cutting, brought to the required form, the next<br />
object is to polish the facets, and at the same time to<br />
redress any little inequalities that may have taken place in<br />
the cutting. The polishing-mill is an extremely simple
fill<br />
OX GRINDING. 159<br />
machine, consisting of a circular horizontal plate<br />
of cast-<br />
iron, fourteen or fifteen inches in diameter, called a skive,<br />
suspended on a spindle, and capable of being put into rapid<br />
motion by means of a larger wheel, five or six feet in<br />
diameter, and turned by an assistant.. From the centre to<br />
the circumference of the iron plate, are lines* or shallow<br />
grooves, formed by rubbing it in that direction with a fine<br />
serve to retain the mix-<br />
grained gritstone : these grooves<br />
ture of oil and diamond-powder with which the plate is<br />
charged. In order to keep the diamond perfectly steady<br />
while the polishing of each facet is going on, the following<br />
contrivance is had recourse to : a copper cup, called a dopp,<br />
about three quarters of an inch in depth and in width, and<br />
furnished with a stem about four inches long of stout<br />
copper wire, is filled with plumbers' solder, which also pro-<br />
jects in a conical form beyond the rim of the cup<br />
apex of this cone, the solder being softened by heat, the<br />
diamond is imbedded with one of the facets projecting.<br />
The stem of the cup is now put into very powerful pincers,<br />
which screw up with a nut and a wrench or lever, and thus<br />
: in the<br />
hold it perfectly tight. The handles of the pincers (made<br />
of wood, and called tongs) are broad, and terminate in two<br />
feet, about an inch high, so that when laid horizontally,<br />
they are supported exactly as a pair of candle snuffers are,<br />
the studs fixed to the handles of the snuffers representing<br />
ing the legs of the pincers, and the single stud near the<br />
point of the snuffers representing the inverted copper cup<br />
holding^the diamond is placed on the plate, the pincers rest-<br />
ing on their legs on the wooden bench or. table that supports<br />
the plate, and pressing at the same time against an<br />
upright iron peg ; the broad part of the pincers between<br />
the legs and the^diajnond, is then loaded with weights,<br />
both to steady the machine, ^ind to increase the pressure of<br />
the diamond against the skive. Matters being thus ad
160 A POPULAR TREATISE OX GEMS.<br />
on the<br />
justed, a little oil and diamond powder is dropped<br />
plate, it is set in motion at the rate of about two hundred<br />
revolutions in a minute, and the process of grinding down,<br />
and at the same time of polishing, is begun. The diamond<br />
is taken up and examined from time to time, and is adjusted<br />
so as to give -the facet its true form. The heat occasioned<br />
by the friction is at all times pretty considerable, and when<br />
the pincers are heavily laden, it occasionally increases to<br />
such a degree as to soften the solder and displace the dia-<br />
mond. This is a serious accident, frequently occasioning a<br />
flaw in the diamond, and always tearing up the surface of<br />
the skive, so as to damage it very considerably. There is<br />
room on the skive for three or four diamonds at the same<br />
time ; and to give each its proper share of attention, is as<br />
much as one person can well manage. The completion of<br />
a single facet often occupies some hours."<br />
The polish is often produced by rubbing the diamond<br />
with a cloth or bare hand. The form which the gems have<br />
to receive from the lapidary varies according to the condi-<br />
tion of the stones; and the skill of the artist consists in the<br />
right selection of a form which shall correspond with the<br />
natural structure of the gems. A good cut has the greatest<br />
influence on the lustre and beauty of gems ; the colorless<br />
and limpid gems, for instance, require a different form from<br />
those which have a play of colors. With a diamond, the<br />
form must correspond as much as possible with its natural<br />
or original shape, in order to save the great trouble of<br />
grinding, and the waste thereby produced. Transparent<br />
gems ought not to be cut too thick ; the rays of light<br />
might otherwise be refracted too much, or prevented from<br />
penetrating through them at all : in the first instance, the<br />
lower facets do not act in correspondence#with the upper,<br />
and the rays are much distributed before reaching the eye.<br />
Gems of such description are called clotty. On the other
FOKMS OF THE DIAMOND. 161<br />
hand, if the gems are too thin, their beauty, elements, and<br />
general<br />
value are likewise diminished. There is a definite<br />
proportion of thickness to the breadth of colorless or limpid<br />
gems, whereas the cut of the colored gems -depends upon<br />
the intensity of the color.<br />
POEMS OF THE DIAMOND.<br />
Diamonds were formerly cut according.to their natural<br />
form, and mostly in the planes of the octahedron. They<br />
were called then point diamonds (pierres de nature, oi-<br />
pointes ingenues).<br />
The following forms are now, more or less, adopted by<br />
the Dutch and English diamond-cutters :<br />
A.. The 3rittiant. This cut displays to greatest advan-<br />
tage the lustre of the diamond : it may<br />
be considered as<br />
obtained by two truncated pyramids, united together by one<br />
common base, the upper pyramid being much more deeply<br />
truncated than the lower. It is formed<br />
a, of the crown, or that part of the<br />
stone which remains visible after the<br />
stone is mounted ; b, the collet, or lower<br />
part ; c, the girdle,<br />
or the common base<br />
for the crown and eollet ; d, the table, the plane which is<br />
formed by the truncature of the upper pyramid ; e, the<br />
bisel, that space which lies between the girdle and table ;<br />
and f, the collet-side, the space between the girdle and<br />
collet. The English lapidaries cut the girdle sharp, where-<br />
as the Dutch leave it broad : the crown amounts to one<br />
third, and the collet to two thirds of the whole height of<br />
the diamond ; the tafole amounts to four- ninths of the<br />
diameter of the brilliant, whereas the collet only needs one<br />
fifth of the size of the table. The table and collet are<br />
regular octagons, and the facets occupied by the bisel are
162 A POPULAR TREATISE ON GEMS.<br />
eight lozenges, with twenty-four triangles, and are called<br />
the star-facets / the facets occupied by the collet-side are<br />
four irregular pentagons, alternating with as many irregular<br />
lozenges, radiating from ^the collet as a centre, and are<br />
bordered by sixteen triangular facets adjoining<br />
the girdle, and are generally called the<br />
pavilion or cro'ss facets. According to the<br />
number of facets, the brilliants receive their<br />
either of double or treble brilliant : the<br />
names,<br />
double brilliant is surrounded by two rows of<br />
facets on the bisel, which are . triangular, and<br />
meet each other the treble brilliant has ; fifty-<br />
eight planes, fifty-six facets, table and collet, thirty-two<br />
the star aud<br />
facets of which are in the bisel in three rows ;<br />
pavilion facets are triangular,<br />
the intermediate ones are<br />
four-sided, -and on the collet-side are twenty-four facets.<br />
The English double brilliant consists of twenty-four<br />
facets, table and collet, sixteen<br />
form of a star in the bisel.<br />
of which terminate in the<br />
Brillionets, or half-brilliants, are those diamonds, the<br />
spread of which is too great in proportion to their depth,<br />
and the crown is only cut like a brilliant, but the collet-side<br />
is. wanting.<br />
J5. The Hose-Diamond has a crown,<br />
but no collet ;' it is formed of equilateral<br />
triangles,<br />
and consists of two rows of<br />
three-sided facets ; those on the girdle<br />
are pavilion, and the others star facets.<br />
But there are variations in the number of<br />
facets : the Dutch roses have eighteen pavilion and six star<br />
facets; others have six pavilion aijd six star facets, or<br />
twelve pavilion and six star facets ; and some, also, have<br />
twenty-four three-sided pavilion and twelve^ star facets.<br />
The rose-diamond is only that diamond, the, proportion of
FORM OF GEMS. 163<br />
whose breadth to its depth is too much extended, and<br />
which would not, without ranch loss, make a good brilliant.<br />
There are fragment rose-diamonds, which are very small,<br />
and ear-drop roses.<br />
C. The Table-Diamond is that stone which<br />
is very flat and of little depth, and which re-<br />
flects but little lastre. They have a table with<br />
four planes and eight facets, and, in order to<br />
make the best of their lustre, they^eceive a brilliant cut.<br />
D. The Bastard-Diamond is that diamond whose cut<br />
is mixed up from the above forms.<br />
There are a few more forms given to those diamonds<br />
which are found unfit for any of. the above cuts, such as<br />
the thick-stones, the portrait-diamonds, the sen ail-diamonds,<br />
which are, however, all unfit for the above cuts.<br />
FORM OF GEMS.<br />
The gem lapidary occupies himself not only with grinding<br />
the common and rare gems, but also pastes, &c. He<br />
uses likewise wheels, but of different material from those<br />
for-diamonds. His wheels are either of copper, if for very<br />
hard stones, or of lead or pewter for softer stones ; he has<br />
likewise polishing wheels. If a wheel is too soft for very<br />
hard stones, he cuts furrows in it, which are then filled out<br />
with rotten-stone or tin-ashes ;<br />
or if very hard stones, such<br />
as sapphire, .are to be ground, the diamond powder is<br />
used for the same. Tin wheels are used for hard stones ^<br />
water, or oil of vitriol, is used for moistening the wheels.<br />
The gems (in order to grind them or to give their<br />
facets)<br />
are cemented into a handle, at the end of which is a<br />
composition<br />
of resin and brickdust. Particular attention<br />
is required in grinding the colored, gems, as the greatest<br />
effect may be produced by their "thickness ; pale-colored<br />
gems require to be left thicker .than darker ones ;<br />
on the
164 A POPULAR TREATISE ON GEMS.<br />
other hand, they ought not to be left too thick, as they<br />
will appear too dark, and thereby 'lose, their lustre. The<br />
same proportion in the manner of cutting the crown and<br />
collet of the colored gems has to be observed as with the<br />
brilliant ; namely, the crown ought to be one third and the<br />
collet two thirds in size of the depth of the whole stone; if<br />
the gem be of a pale color, the collet ought to be three<br />
fourths of the size ; and if of a darker color, much less ; the<br />
table of those colored g^ns which require to be heightened<br />
ought to be waved somewhat, whereas it ought to be even<br />
in darker gems. The forms received by the colored gems<br />
in cutting resemble, in many instances, those of the dia-<br />
mond; but the following-are the additional ones they receive,<br />
according to the nature of the shape and color of the<br />
stone :<br />
A. The Step or Pavilion cut. The planes,<br />
which are long and small, decrease towards<br />
the table and collet, and terminate in steps ;<br />
the crown has usually two, and the collet four<br />
or five facets on each side; the form of the<br />
stones may be of four, six, eight, or twelve sides, or nray<br />
be long or round. This cut is particularly applicable to<br />
colored gems, as it reflects the light in a high degree, by<br />
which the play of color is much raised ; and it is at all<br />
events to be preferred in the collet of colored gems, even'<br />
to those brilliants in pavilion : the crown may be of any<br />
form whatever.<br />
JB. The Mixed facet cut- is a com-<br />
pound of Brilliant and pavilion cuts, the<br />
first being on the crown ;<br />
it is. a very fa-<br />
vorite cut for colored gems, and con-<br />
tributes much in raising 'the lustre.
FOKM OF GEMS. 165<br />
C. .The Elongated Brilliant facet cut,<br />
which, if the brilliant facets are on the<br />
crown elongated, and the collet has a<br />
pavilion cut, is very appropriate to long<br />
and thin stones.<br />
D. The Table cut, having either an uneven or<br />
conchoidal table, with one or two rows of facets,<br />
in a circular form, around it : a very useful form<br />
for seal-stones.<br />
E. The Double facet cut, the crown hav-<br />
ing two rows of facets, and the collet the<br />
pavilion form; this cut is well adapted to<br />
such stones as require the concealment of<br />
any faults, flaws, or fissures.<br />
F. The Cabochon cut, is either flat, convex, or double-<br />
convex that is, arched ; it may<br />
be on both<br />
sides, or only on one. This cut is particularly<br />
applicable for semi-transparent gems, or those which display<br />
or<br />
their peculiar colors, such as the opal, moonstone, &c. ;<br />
coUect the light<br />
in a small space, on one or several points,<br />
according to the convexity they have received. The cabochon<br />
cut may have one, two, or more rows<br />
of facets, and opaque stones receive with ad-<br />
vantage the facets over the whole surface.<br />
Garnets, for instance, which are generally of<br />
a dark color, are cut en cabochon, the lower<br />
plane excavated in a circular form, and the upper plane all<br />
around with facets. -Other gems, the interior faults of<br />
which cannot be concealed, may be improved by this cut,<br />
giving them more transparency, vividness of color, and a<br />
greater degree of fire.<br />
A judicious choice of 'the form in which any particular<br />
gem shah<br />
1<br />
be cut, depends on the skill and discrimination<br />
of the artist.
166 A POPULAR TEEATISE ON GEMS.<br />
COMMON LAPIDAKT.<br />
Such common precious stones as are suitable to be cut<br />
for snuff-boxes, rings, grinding mortars, seals, and earrings,<br />
are wrought by the common lapidary, by means of<br />
copper or iron wheels revolving vertically. The tools are<br />
generally of iron, and sometimes brass ; some are flat like<br />
chisels, gouges, ferrules, and some others have coriicular<br />
heads. The polish is given with rotten-stone, on a tin plate,<br />
or with crocus martis, on a wooden plate covered with felt.<br />
The cuts applied by the workmen are either even, cup-shell<br />
form, excavated, elevated, or quite simple facets are not<br />
;<br />
used by him.<br />
Mr. Mawe describes a lapidary's apparatus, fit for polishing<br />
minerals, shells, &c., and which may be placed in a<br />
parlor, where every operation of polishing, on a scale suffi-'<br />
ciently large, may be effected, and pebbles may be slit of<br />
three or four inches diameter. It consists of the following<br />
mills:<br />
1st. A lead mill, or wheel, to be used with emery and<br />
water, for grinding down substances preparatory to pol-<br />
ishing.<br />
2d. A pewter mill, to be used with rotten-stone a little<br />
wet, for polishing.<br />
3d. Tin plate, properly prepared, the edge of which is<br />
to be used with diamond powder, to slit or cut hard stones<br />
asunder.<br />
4th. Wood iriills, covered with leather, &c., for polishing<br />
marble, alabaster, shells, or other soft substances.<br />
ENGBAVING.<br />
The value of many precious stones is increased by en-<br />
graving them. The common gems have, for several centu-
ENGRAVING. 167<br />
ries, been used in heraldry. In Italy, Germany, and England,<br />
we find the coat of arms of distinguished or noble<br />
families engraved on stone. The machine used for such<br />
purposes is like that of the i glass cutters, with this difference,<br />
that finer and harder instruments, and sometimes<br />
diamond splinters, are required for -this work. Before the<br />
stone can be cut or engraved, its surface, after having re-<br />
ceived the proper shape and form required, is rubbed with<br />
emery,* glass, or leaden wheels. The artist now makes his<br />
drawing with a brass pin, and executes it afterwards with<br />
his tools. On hard stones he uses diamond powder ; on<br />
soft, emery and oil.<br />
The engraving of armorial bearings, single figures, de-<br />
vices, &c., on -any gem, is performed by means of a small<br />
iron wheel, the ends of the axis of which are received within<br />
two pieces of iron in a perpendicular position, that may or<br />
may not be closed as the operation requires ; the tools are<br />
fixed to one end of the axis, and .screwed firm ; the stone<br />
to be engraved is then held to the tool, the wheel set in<br />
motion by the foot, and the figure or device gradually<br />
formed.<br />
'<br />
*<br />
Difficult works are executed after models of plaster of<br />
Paris, of clay, or other substances ;<br />
the polish is afterwards<br />
given on wheels, provided with brushes or with rotten-stone.<br />
The semi-transparent and opaque stones are more used for<br />
engraving than the transparent gems, because the drawing<br />
will not show distinctly through them, on account of the<br />
great refraction of light ;<br />
the same is the case with irides-<br />
cent or shining stones. The engravings are generally bas-<br />
relief or raised ; those having layers are mostly preferred<br />
for cameos ; for instance, the onyx, sardonyx, and chalce-<br />
dony; also wood-opal, which is constantly exported from<br />
Germany for the'Italian artists in Rome.
168 A POPULAR TREATISE OX GEMS.<br />
SAWING AND DRILLING GEMS.<br />
Gems and precious stones often require to be sawed in<br />
different directions, which operation is performed on a<br />
machine like that of a lapidary, with the exception of a<br />
polishing plate, for which is substituted a cutting plate<br />
having sharp ends, or by fastening the stone on a stand,<br />
and moving continually a fine iron or copper wire stretched<br />
in a bow, which is moistened with emery and oil-. Care<br />
has, 'however, to be taken, not to let the stone grow too<br />
hot, as the heat may crack or make it spotty. The Chinese<br />
use strings spun over in preference to the wire, they<br />
having the advantage of keeping the emery sticking to<br />
them, and of accelerating thereby the operation. For<br />
drilling gems or other precious stones, a diamond set in<br />
steel is made use of, to move to and fro by a bow, or the<br />
common engraving machine, the drilling instrument of<br />
which consists of an iron point, to which is fastened a diamond<br />
splinter, which is pressed upon the stone while' it is<br />
revolving upon the plate.<br />
GRINDING AND POLISHING MATERIALS.<br />
The materials for grinding and polishing vary according<br />
to the hardness of the gem. The diamond powder is ob-<br />
tained by grinding real diamonds, which are unfit for use,<br />
with each other in a hollow cylinder of cast iron, in which<br />
another one exactly similar is used for the most costly and<br />
the hardest gems. Corundum, sapphire, topaz powder,<br />
and emery powder, are commonly used for grinding and<br />
polishing the diamond. It is well to remark that emery is<br />
often adulterated by a mixture of quartz and oxide of iron,<br />
or by garnet or iron powder. Emery fit for the use in-<br />
tended requires to be properly pulverized and levigated.
HEIGHTENING THE COLOR- OF GEMS. 169<br />
According to Hawkins, the following method is pursued in<br />
England : The emery is pulverized in an iron mortar and<br />
passed through different sieves, one finer than the other ;<br />
the first is levigated with oil, which keeps it in better<br />
suspension in water ; according<br />
to the time in which the<br />
powder settles, the different numbers are obtained.<br />
For polishing the different precious stOnes, hard and soft<br />
gems, the diamond powder and emery are mostly used.<br />
Rotten-stone, tin-ashes, pumice-stone, oxide of iron, English<br />
jewellers'-red, are all used in their finest pulverized state.<br />
A great deal depends upon the polish wrhich a gem has received<br />
all its other ;<br />
superior qualities being thereby called<br />
forth.<br />
HEIGHTENING THE COLOR OF GEMS.<br />
Since color is one of those characters which is the most<br />
tempting in the sale of gems and jewelry, ah1<br />
means are<br />
ployed for heightening the same, and covering any real<br />
defect. Foil of small thin metallic substances, colored or<br />
uncolored, either of fine silver or copper, is placed under<br />
the gem in the back of the mounting, which heightens the<br />
color and lustre, particularly of the transparent gems.<br />
Almost all gems were formerly set in black-colored backs,<br />
composed of burnt ivory-black and gum mastic, but are<br />
now mostly set d jour, which is, leaving the lower part of<br />
the stone uncovered in setting, and only mounting around<br />
the girdle an old method, and very applicable to perfect<br />
stones, where no defects require concealment.<br />
Foiling materially heightens the lustre of gems. The<br />
rose-diamond al\*ys requires it on account of its flat form.<br />
There are many gems which would not produce any effect<br />
without the foil ; it is therefore used whenever a pale or<br />
impure color is to be raised, or when the'gems are to be<br />
protected against dust or moisture in order to produce a<br />
8
170 A POPULAR TREATISE ON GEMS.<br />
uniform shade of color ; the foil forms then a suitable ap-<br />
plication.<br />
The coloring of the foil is generally performed by the<br />
jewellers. Isinglass, first dissolved in water and afterwards<br />
boiled in spirits of wine, and then strained, is the mass or<br />
body to which the colors are afterwards added, which are<br />
also soluble in water.<br />
For producing a red color, the best material is carmine,<br />
"<br />
"<br />
"<br />
"<br />
blue<br />
yellow<br />
"<br />
"<br />
"<br />
"<br />
litmus,<br />
saffron.<br />
To produce the different shades and varieties of color, the<br />
above are mixed in different proportions with each other.<br />
Very clear stones, such as chfysoprase, carnelian, &c., are<br />
sometimes painted on the back. The Paris jewellers are<br />
very skilful in painting stones of inferior value so as to deceive<br />
even professional men it is for this reason that ;<br />
gems<br />
when set ought not to be purchased ; the valuable gems<br />
which have a foil on their back are mostly set in such a<br />
manner that they may be examined without the same.<br />
Foiled gems may likewise be distinguished by holding .the<br />
table of the set gem on the nail of the thumb and observing<br />
the passage of light through the crown.<br />
In the East, rubies are never set with foil, but a cavity is<br />
made in the lower part and filled with finely polished gold,<br />
which raises their lustre remarkably.<br />
Fissures, flaws, or veins, in the interior of gems, are<br />
mostly concealed by the foil, and when near the girdle,<br />
are covered by the mounting.<br />
The defects of stones are sometimes concealed by color-<br />
ing the case with mastic and ivory-black, find according to<br />
circumstances leaving blank the spot of the faulty stone,<br />
or covering only the spot, so as to produce a uniform color.<br />
Another, and not unusual method of concealing fissures,<br />
flaws, or other faults, is to cut those stones that have many
SETTING OF GEMS. . 171<br />
faults the momentary detection of these faults being there-<br />
by prevented from the play of the refracting light and the<br />
lustre. The color of many gems is raised by fire, which<br />
acts in a peculiar manner on them ; thus the. Brazilian topaz<br />
assumes a very fine pale-red color, by burning. The process<br />
of effecting this coloring is very simple, viz : after wrapping<br />
the topaz in a sponge, ignite the same and keep it burning<br />
until consumed.<br />
The zircon sometimes assumes a better color after having<br />
been subjected to a high degree of heat. Amethysts hav-<br />
ing dark spots may be calcined for a short time in a cruci-<br />
ble containing sand and iron filings, under which process<br />
they mostly lose those faults ; but if exposed to an excess<br />
of heat, they will lose their color altogether, and become<br />
as white as quartz.<br />
The Oriental camelian assumes, after<br />
burning, a fine color, and in Hindostan those carnelians<br />
which are found detached in the mines are cut up and<br />
burnt on the spot. Very fine cracks are some.times produced<br />
in mounting stones, which may be repaired and concealed<br />
successfully by means of garlic juice. When stones<br />
are broken by the same operation they may be cemented<br />
by gum mastic.<br />
SETTING OF GEMS.<br />
The gems are generally fastened or set at the girdle in<br />
a box or rim of metal : limpid and faultless gems are always<br />
set d jour, i. e., without backs, since they appear<br />
then to<br />
the best advantage, and if the gem is intended to display<br />
its full size and color, the djour setting is only fastened by<br />
small shanks or claws. The good setting of a gem very<br />
much increases its value and beauty. The material for<br />
mounting the limpid gems is silver, which displays them to<br />
more advantage than gold. In order to increase the color<br />
or lustre of large gems, they are often surrounded by
1'72 A POPULAR TREATISE ON GEMS.<br />
smaller gems, such as small roses, rabies, emeralds, garnets,<br />
turquoise, &c.<br />
The jewellers' wax used for mounting gems is made of<br />
three parts rosin, one part beeswax, and four parts fine<br />
brickdust.<br />
CLEANING THE GEMS.<br />
The following composition I have found to be the best<br />
for thoroughly cleaning gems, particularly when set : Take<br />
one part flowers of sulphur and two parts of rotten-stone<br />
or bone-ashes, which, when mixed, is used by it rubbing on<br />
a piece of buckskin, and with that and a stiff hair-brush, al-<br />
ternately rubbing the gems, finishing with a softer skin or<br />
cloth to remove the dust.<br />
IMITATIONS OF GEMS.<br />
Pliny mentions the imitation of jewels by glass fluxes,<br />
and it is sufficiently proved that the ancients were far ad-<br />
vanced in this art. The Egyptian mummies were provided<br />
with glass buttons of green an blue color, and during the<br />
reign of the Roman empire, colored glass was very general ;<br />
and we find antique cameos carved in various colored glass,<br />
representing the onyx ; likewise colored glass cemented<br />
with real onyx ; but they never attained such perfection in<br />
their art as to set at defiance the skill of the artist and<br />
jeweller to distinguish between the genuine and spurious<br />
ones. The imitation of gems may be divided into three<br />
classes :<br />
A. The Pastes. The basis of these imitations is a fine,<br />
pure, and white glass composition, called strass, after its<br />
inventor, Strass of Strasburgh, in the seventeenth century,<br />
who first conceived the importance of imitating the real<br />
gems as respects their hardness, specific gravity, and re-
IMITATIONS OF GEMS. 17*3<br />
He accomplished the task so far that in<br />
fraction of light.<br />
many instances, either all three, or one or the other of his<br />
objects, were attained. The strass is composed of silex<br />
(quartz, flint, or pure sand), potash, borax, red lead, and<br />
sometimes arsenic. To 300 parts of silex add 96 parts potash,<br />
27 parts borax (prepared from the boracic acid), and<br />
514 parts of white lead, and 1 part arsenic; or according<br />
to another method, mix V ounces and 24 grains of quartz<br />
with 10 ounces and 7J drachms red lead, 3 ounces and 6<br />
drachms pure pearlashes, 3fJ drachms borax, and 12 grains<br />
arsenic. The mixture is put into a covered Hessian cruci-<br />
ble, and kept at a great heat in a pottery furnace for<br />
twenty-four hours. The longer the mass is kept in a fluid<br />
state the harder and clearer it will be when turned out and<br />
cooled. This discolored strass is used by the lapidaries for<br />
imitating the" diamond, rock-crystal, and white topaz.<br />
For imitating the colored gems various colored ingre-<br />
dients are employed. To obtain that intensity- of color ap-<br />
proaching nearest to the original gem, it is experience<br />
alone which can guide the manufacturer. In order to imi-<br />
tate the uniform and intense colors, the strass coloring in-<br />
gredients are to be of the finest powder, and very intimately<br />
mixed; the mass is then to be exposed to a very great<br />
heat, and in that state left for nearly thirty hours, so that<br />
the cooling may be gradual. Numerous establishments in<br />
Germany and France are now engaged in the manufacture<br />
of the strass and colored pastes, each of which possesses<br />
secrets, acquired by experience, for producing these articles<br />
in the greatest perfection.<br />
A. Artificial Topaz. Take of perfectly white strass one<br />
ounce and six drachms, glass of antimony thirty-seven<br />
or add to six ounces<br />
grains, and cassius purple one grain ;<br />
of strass half a drachm of crocus martis.<br />
B. Artificial Ruby. This may be obtained, from the pre-
1*74 A POPULAR TREATISE ON GEMS.<br />
ceding mixture for the topaz by the addition of eight parts<br />
more of strass, and left for thirty hours in fusion ; when<br />
taken out and fused before the blowpipe, it yields a most<br />
beautiful Oriental ruby. Five ounces strass and one drachm<br />
oxide of manganese may be employed for the same pur-<br />
pose, but will not make so fine a ruby. Or by calcining<br />
ammoniacal alum with chromate of potash and lampblack,<br />
which forms the composition of<br />
97 parts alumine,<br />
1<br />
2<br />
"<br />
"<br />
oxide of chrome,<br />
silica and lime.<br />
C. Artificial Emerald. To one pound of strass add one<br />
drachm of verdigris and fifteen grains crocus martis.<br />
D. Artificial Sapphire. Add to eight ounces of strass<br />
fifty-two grains pure oxide of cobalt.<br />
E. Artificial Amethyst. To eight ounces of strass add<br />
thirty grains oxide of manganese, twenty-four grains oxide<br />
of cobalt, and forty grains cassius purple ;<br />
or to one pound<br />
of strass, twenty grains oxide of manganese, and one grain<br />
oxide of cobalt.<br />
F. Artificial Aquamarine. To six ounces of strass add<br />
twenty-four, grains glass of antimony, and one and a half<br />
grain oxide of cobalt.<br />
C. Artificial Syrian Garnet. To one thousand grains of<br />
strass add five hundred grains glass of antimony, four<br />
grains cassius purple, and four grains oxide of manganese.<br />
Messrs. Bouillette, Hyrclin & Co., Rue St. Avaye; Savany<br />
& Mosbach, Rue Vaucauson, in Paris; and Henrys & Co., of<br />
London, have contributed to the great London Exhibition,<br />
in 1851, a great display of their manufactures in artificial<br />
stones, such as diamonds, .emeralds, sapphires, and pearls.<br />
The latter were particularly brought to perfection by Mr.<br />
Constant Vales, Rue St. Martin,- Paris,<br />
as the imitation<br />
pearls by that gentleman were superior to any thing the
IMITATIONS OF GEMS. 175<br />
author had ever seen before, and were, to appearance,<br />
quite equal to the natural pearls.<br />
The following table, taken from Booth's Encyclopedia,<br />
shows the proportions of the various ingredients for the<br />
different colored pastes :<br />
Topaz. Ruby. Amethyst. Garnet. Sapphire. Aq. Mar. Emerald.<br />
Colorless Paste 1000 1000 1000 1000 1000 1000 1000<br />
Antimony Glass<br />
Oxide of Manganese..<br />
40<br />
..25<br />
..<br />
8<br />
500<br />
4<br />
.. 7<br />
Gold Purple 1 .. >/ 4<br />
Oxide of Cobalt 5 .. 15 /<br />
Oxide of Copper .. .. 8<br />
Oxide of Chrome . . . . .'. Ys<br />
Colored glass is also very frequently cut in forms and<br />
shapes so as to resemble gems, and the various colors are<br />
produced by melting the best qualities of glass materials<br />
with the folio whig oxides :<br />
Yellow is produced by charcoal, antimonite of potassa,<br />
silver, and oxide of uranium.<br />
iron.<br />
Blue, by oxide of cobalt, and a mixture of copper and<br />
Green, by oxide of copper or of chrome, or by antimo-<br />
nite of potassa, litharge, and cobalt.<br />
Red, by gold, suboxide of copper, and oxide of iron.<br />
Violet, by manganese.<br />
Black, by protoxide of uranium, iridium, platinum, and<br />
by a mixture of manganese, copper, iron, and cobalt.<br />
White, by oxide of tin, arsenic, and bone'-ashes.<br />
By combining one or more of these oxides various shades<br />
and hues may be obtained ; the yellow glass of antimony<br />
the use of a little<br />
may be shaded more into orange by<br />
oxide of iron ; the purple-red of gold passes into carmine<br />
the blue of cobalt may be<br />
by employing silver with gold ;<br />
shaded into purple by a little gold into ; green by antimony,<br />
'
176 A POPULAR TREATISE ON GEMS.<br />
or other yellow colors ; a rich grass-green is obtained from<br />
oxide of chrome, with a little antimony and litharge ; a<br />
brilliant emerald-green from a mixture of oxide of uranium<br />
and nickel oxide of nickel alone ;<br />
yields a hyacinth-red.<br />
The Bohemian garnet is prepared by fusing together 100<br />
parts quartz, 150 parts red lead, 30 parts potash, 20 parts<br />
fused borax, 5 parts crude antimony, 5 parts manganese,<br />
and 6 parts fulminating gold ground up with oil of turpen-<br />
tine.<br />
Turquoise is imitated by oxides of copper<br />
and cobalt.<br />
Opal, by adding oxide of tin and bone-ashes to the glass, in<br />
small quantities.<br />
The following colored pastes were recommended by<br />
me twenty years ago, to the American manufacturers of<br />
colored glass, and have all proved successful :<br />
JStrass.<br />
1<br />
This is the basis for ah pastes ; it is very hard, and gives<br />
sparks when rubbed on steel.<br />
1 ounce of powdered glass, 2 drachms burnt borax,<br />
3 drachms "<br />
quartz, 40 grains of saltpetre,<br />
'<br />
3<br />
" red lead, 30<br />
"<br />
white arsenic.<br />
This composition is exposed to a white heat in a covered<br />
crucible for thirty hours.<br />
I ounce of powdered rock-crystal<br />
or quartz,<br />
Ruby.<br />
3 drachms of red lead,<br />
15 grains of eassius purple,<br />
i ounce of dried carbonate soda, 8 " metallic antimony,<br />
4 drachms of burnt borax,<br />
8<br />
" oxide manganese.<br />
It "<br />
saltpetre,<br />
Or by taking<br />
1 ounce of powdered rock-crystal,<br />
i "<br />
dry carbonate soda,<br />
40 grains saltpetre,<br />
15 "<br />
purple cassius,<br />
80 grains of burnt borax,<br />
1 drachm of sal ammonia.
Take<br />
It ounce of ground rock-crystal,<br />
6 drachms of dry soda,<br />
2 " " borax,<br />
Or mix<br />
1 ounce of rock-crystal,<br />
"<br />
y<br />
dry soda,<br />
3 drachms " borax,<br />
"<br />
It<br />
red lead,<br />
IMITATIONS OF GEMS.<br />
Sapphire.<br />
2 drachms of red lead,<br />
1 "<br />
saltpetre,<br />
1 grain, of carbonate cobalt.<br />
.t drachm of saltpetre,<br />
By means of the carbonate of copper.<br />
It ounce of rock-crystal,<br />
6 drachms of soda,<br />
1 borax,<br />
Take-<br />
it ounce of rock-crystal,<br />
6 drachma of dry soda,<br />
2 " " borax,<br />
2 " red lead,<br />
1 ounce of rock-crystal,<br />
"<br />
t<br />
dry soda,<br />
2 drachms of dry borax,<br />
2 "<br />
. red lead,<br />
9 drachms of rock-crystal,<br />
8<br />
2<br />
1<br />
"<br />
"<br />
"<br />
dry soda,<br />
red lead,<br />
saltpetre,<br />
It ounce of rock-crystal,<br />
t "<br />
dry soda,<br />
8 drachms of burnt borax,<br />
2 " red lead,<br />
20 grains of saltpetre,<br />
Emerald.<br />
Green Color.<br />
Canary.<br />
Chrysoprase.<br />
i grain of carbonate cobalt,<br />
15 " "<br />
copper.<br />
1 drachm red lead,<br />
t<br />
"<br />
saltpetre,<br />
t " carbonate of copper.<br />
1 drachm of saltpetre,<br />
20 grains of red oxide of iron,<br />
10 "<br />
green carbonate of<br />
copper.<br />
40 grains of saltpetre,<br />
It<br />
10<br />
"<br />
"<br />
carbonate cobalt,<br />
"<br />
chrome.<br />
80 grains of oxide of uranium,<br />
3 " carbonate of copper,<br />
oxide of tin,<br />
white b'nt bone-ashes.<br />
2 drachms of white bone-ashes,<br />
2 grains of carbonate of copper,<br />
4 " red oxide of iron,<br />
6<br />
"<br />
oxide of chrome.
178 A POPULAR TREATISE ON GEMS.<br />
Opal.<br />
9 drachms of rock-crystal,<br />
15 grains of saltpetre,<br />
8 "<br />
"<br />
dry soda, /io<br />
cassias purple,<br />
2 " burnt<br />
"<br />
borax, Iff<br />
bone-ashes,<br />
li<br />
" red lead, 2<br />
"<br />
muriate silver.<br />
Is ounce of rock-crystal,<br />
1<br />
"<br />
dry soda,<br />
Aquamarine.<br />
*<br />
1 drachm of saltpetre,<br />
6 grains of red oxide of iron,<br />
8 drachms of burnt borax, 2 " carbonate of copper.<br />
2 " red lead,<br />
Hyacinth.<br />
The above mixture, with the addition of ten grains of the<br />
oxide of manganese.<br />
Garnet.<br />
9 drachms of rock-crystal,<br />
40 grains of saltpetre,<br />
8 "<br />
dry soda, 5 " oxide of manganese,<br />
2<br />
" burnt borax, 3 " "<br />
iron,<br />
li<br />
" red<br />
"<br />
lead, 1<br />
cassius purple.<br />
Rubellite, Red Tourmaline.<br />
1 ounce of rock-crystal,<br />
1<br />
"<br />
dry soda,<br />
1 drachm of red lead,<br />
'<br />
H "<br />
saltpetre,<br />
8 drachms of burnt borax,<br />
8 grains of oxide of nickel.<br />
Indigolite^ or Blue Tourmaline.<br />
The above mixture, with the addition of the carbonate<br />
of cobalt.<br />
6 drachms of rock-crystal,<br />
2 "<br />
dry soda,<br />
14 "<br />
burnt borax,<br />
'<br />
Chrysolite.<br />
Amethyst.<br />
1 drachm red lead,<br />
10 grains of saltpetre,<br />
2<br />
"<br />
oxide of manganese.<br />
But 1 grain of the oxide of manganese to each ounce of<br />
the mass.
IMITATIONS OF GEMS. 179<br />
Turquoise.<br />
In the above mixture use instead of the manganese<br />
5 grains of dry verdigris,<br />
3<br />
"<br />
powder blue,<br />
Lazulite.<br />
By adding to former mixtures^<br />
2 grains oxide cobalt,<br />
Agate.<br />
20 grains of bone-ashes.<br />
1 drachm of burnt bone-ashef.<br />
By mixing together several frits and adding oxide of<br />
iron, several varieties of agate are obtained.<br />
It will now be necessary to show the distinguishing char-<br />
acters between the real and artificial gems, as they so<br />
closely resemble each other that a superficial inspection<br />
will not always enable the examiner to discriminate be-<br />
tween them ; they are as follows :<br />
1. The hardness ; which may be tested on the grinding<br />
machine ; with fine quartz sand it will immediately attack<br />
the pastes, or by scratching with a real onyx, to which the<br />
pastes will immediately yield.<br />
2. The small air-bubbles in the pastes, may more of less<br />
be detected with a good magnifying glass.<br />
3. The cold touch will never remain for any length of<br />
time on the pastes as it will on the real gem.<br />
4. The breath remains much longer on the pastes, on<br />
account of their bad conducting power, than on real gems.<br />
The specific gravity and electricity, may likewise indicate<br />
the difference, but I never depended on them alone, and<br />
I will mention that I once examined the specific gravity of<br />
an artificial topaz which fully corresponded with that of a<br />
Brazilian topaz. Electricity will indicate the difference<br />
between real and artificial gems by the length of its con-
180 A POPULAR TREATISE ON GEMS.<br />
tinuance; for real gems retain, after being rubbed, their<br />
electricity for from six to thirty-two hours, whereas, the<br />
artificial ones only retain it from forty to sixty minutes.<br />
_Z?. The Doublets. This mode of imitating real gems is<br />
called doubling, when a quartz, cut and polished, is ce-<br />
mented by means of gum mastic to another colored paste,<br />
whereby the whole stone assumes the color of the lower<br />
paste. When a real gem' is employed instead of quartz (as<br />
the surface and the quartz or paste is cemented below), it is<br />
called half doubling. This adulteration is carried on to a<br />
very great extent in the East Indies, where they paste any<br />
thin gem to a paste corresponding in color.<br />
The concave doubling is effected by excavating the inside<br />
of a quartz or paste. The cavity being filled with a colored<br />
fluid, and the other part afterwards cemented on it, will,<br />
when well executed, present so uniform a color that it is<br />
difficult even for a judge to detect the deception. The<br />
surest method of detection is to put the specimen in question<br />
in hot water or alcohol, by which the gum mastic will<br />
be dissolved. When set, the only way of finding out the<br />
adulteration, is to put it reversely on the nail of the thumb,<br />
when the false refraction of light or the rainbow colors will,<br />
with certainty, determine its identity.<br />
C. The Burning. This mode of adulterating the real<br />
gems, is performed by coloring cut and polished quartz<br />
specimens. and throwing them into a solution of permanent<br />
pigments, such as a solution of indigo, decoction of cochi-<br />
neal, solution of ammoniacal copper ; the small cavities<br />
produced by the heat will absorb the fluids. The topaz is<br />
burnt by itself, with or without the absorption of a pig-<br />
ment, as also the spinelle, and the quartz ; chalcedony is,<br />
however, frequently burnt to imitate the onyx, and to en-<br />
grave thereon cameos and intaglios.<br />
It 'may be remarked, however, that since the introduc-
GEMS FOB OPTICAL PURPOSES. 181<br />
tion of colored pastes, very few adulterations of this kind<br />
are now practised, and we see but rarely such doublets and<br />
burnt stones.<br />
PRICE OF AJSD TRADE IN GEMS.<br />
It is difficult to determine the price of gems without<br />
reflecting upon all the circumstances relating to them, such<br />
as beauty and uniformity, the play, the lustre, and the<br />
vivacity of the colors, and also on the perfection of the cut,<br />
the polish, the rare locality, the size of the individual gems.<br />
It depends upon the trade of the various countries whence<br />
they come, and what quantity of such valuable gems may<br />
be had at one time at any of the great cities : we find that<br />
diamonds re often sold at a much less price in London<br />
and Paris than in Brazil. The principal trade, however,<br />
is as yet carried on in Brazil and the East Indies, although<br />
it is in no comparison so prosperous as in former years.<br />
The gems are sold by weight, as carat and grain-. One<br />
carat is equal to four grains, and forty-four carats are equal<br />
to one ounce. The name carat is derived from the word<br />
kuara, the coral-tree (erythrina), the red pods of which",<br />
when dry, were formerly used for weighing gold dust, and<br />
each of them weighs four grains, which is equal to one carat.<br />
GEMS FOR OPTICAL PURPOSES.<br />
A few- years ago, Massrs. Trecourt and Oberhauser laid<br />
before the Parisian Academy lenses of the<br />
diamond,,<br />
sapphire, and ruby, which were used in connection with<br />
were of nine-tenths milli-<br />
glass lenses in microscopes ; they<br />
metre, in diameter. The diamond lens magnified two<br />
hundred and ten times, that of sapphire, two hundred and<br />
fifty-five times, and that of ruby, two hundred and thirty-<br />
five times, in linear extension.
182 A POPULAR TREATISE ON GEMS.<br />
A letter was lately published from Sir David Brewster,<br />
on a curious optical phenomenon that had occurred in the<br />
construction of a diagonal lens. The diamond, previous to<br />
working, had all the appearance of internal brilliancy ; but,<br />
after being polished, it presented a series of stratified<br />
shades, which rendered it useless for the required purpose.<br />
It afterwards appeared that lapidaries were acquainted<br />
with this appearance, which rendered them extremely un-<br />
willing to take the risk on themselves, of cutting up diamonds<br />
for optical purposes. On a minute examination of<br />
this phenomenon, it appeared that these different shades<br />
occurred in regular strata, each section being about the<br />
one-hundredth part of an inch, and each stratum having a<br />
different focus, and being of a different degree %f hardness<br />
and specific gravity. The inferences drawn from the above<br />
facts were : that the diamond was a vegetable substance,<br />
and that its parts must have been held in solution and sub-<br />
jected to different degrees of pressure at different stages<br />
of existence. If, on the contrary, as it has been generally<br />
believed, it is subject to the laws of crystallization, its crys-<br />
tals must necessarily be homogeneous.
1 Stt.Beiyl. 2 Emerald. 3 Rube^e. ^BrazaTopas. 5 Rulr/. 6 Star<br />
7 Opal. 8 Hyacinth..
PART III.<br />
CONSIDERATION OF THE INDIVIDUAL" GEMS.<br />
DIAMOND.<br />
DIAMOND: Diamant (German), Adamant (of the an-<br />
The name<br />
cients), Almas (Oriental), Diamant (French).<br />
Diamond is derived from the Greek, Adamas, meaning invincible,<br />
and referring to the hardness of the gem. The<br />
Syrians are said to have first known the diamond, and it<br />
was in early ages the subject of trade to the people of the<br />
East. The Carthaginians are said to have carried on their<br />
trade with the Etrurians, who procured diamonds from the<br />
interior of Africa. Pliny mentions six species of diamonds,<br />
among which, however, the Indian are to be considered<br />
the true, in contradistinction to the quartz crystals, which<br />
were likewise called diamonds in those times. The diamond<br />
was highly esteemed, and many medicinal virtues<br />
were attributed to it, particularly against mania, and as an<br />
antidote for poisons ; it was worn in the rough state. The<br />
art of cutting it with its own powder was discovered in 1476,<br />
it was cut in the<br />
by Lewis Van Berghen. In the beginning<br />
table-form, with one row of facets on the surface ; afterwards,<br />
in 1520, the rhomb cut was : adopted the form of brilliants<br />
was invented in the reign of Louis XII. Cardinal Mazarin<br />
was the first who had diamonds polished in this form, some<br />
of which yet belong to the crown of France. For a long
184 A POPULAR TREATISE ON GEMS.<br />
time philosophers vainly speculated as to the nature of the<br />
diamond ; first it was considered as a mineral, consisting<br />
of silica ;<br />
but Newton was the earliest (1675) who expressed<br />
himself as to the constitution of diamonds. He judged,<br />
from the great refraction of light, that it must be a com-<br />
bustible body, and a series of experiments with it, tested<br />
afterwards by different naturalists, proved the same to be<br />
pure carjbon. The first trial was made in 1694, by the<br />
members of the Academy at Florence, by whom diamonds<br />
were volatilized within the focus of a mirror. Bergman<br />
first classified the diamond among combustible bodies, and<br />
mentions having cut off the head of the gems.<br />
Various views existed in regard to the origin of the diamond<br />
: some considered it as a secretion of a vegetable<br />
substance ;<br />
others as originating from volcanic or plutonic<br />
revolution. The Indians believe diamonds are continually<br />
and the inhabitants<br />
regenerating and growing to this date ;<br />
of Pharrah, in Hindostan, affirm that the quantity of diamonds<br />
by no means decreases, but on the contrary, the<br />
soil will yield a new supply fifteen or twenty years from<br />
the time it is exhausted.<br />
Numerous experiments have been instituted to produce<br />
an artificial diamond from several substances which contain<br />
carbon, and by the application of a high degree of heat.<br />
The late Dr. Hare, in Philadelphia, succeeded in melting<br />
down mahogany charcoal so as to produce a metallic appearance,<br />
by his deflagrator. Professor Silliman likewise<br />
made similar experiments with plumbago, which produced<br />
small globules, some of which were so transparent that they<br />
could not be distinguished from the genuine diamond.<br />
Professor Yanuxem, who examined the globules obtained<br />
from fused charcoal, found them to contain iron and carbon,<br />
which led him to the conclusion that the charcoal had not<br />
undergone a real fusion. Cagniard de Latour pretended
DIAMOND. 185<br />
to have discovered the ingredients for imitating diamonds<br />
of some size ; but Thenard proved those small crystals of<br />
the appearance of diamonds to be some silicates of pecu-<br />
liar composition, which, according to Arago, polarized<br />
light in a different angle from that of diamonds. All<br />
speculative experiments to imitate this most precious gem<br />
by the various compounds of carbon, have hitherto proved<br />
abortive.<br />
The diamond is found crystallized mostly in the form of<br />
an octahedron (composed of t\vo four-sided pyramids, united<br />
by their bases), or rhombic dodecahedron, rarely of a cube ;<br />
but the planes of the angles, are often rounded or bevelled.<br />
The simple octahedron is pretty rare, and still more so the<br />
cube ;<br />
but the dodecahedron, either simple or complicated,<br />
is very frequent ; the crystals are sometimes hemitrope.<br />
In the museum of tne School of Mines are some fine macles,<br />
composed of two crystals crossing each other at right an-<br />
gles. The foliated passages are distinctly parallel<br />
to the<br />
faces of the octahedron, in which direction they may always<br />
be split. The fracture is conchoidal ; surface smooth, often<br />
rough or striped, and sometimes covered with a scaly<br />
of an. ex-<br />
crust; it is transparent, also semi-transparent;<br />
called the diamond or adamantine<br />
ceedingly vivid lustre,<br />
lustre, and when polished, of splendid fire ;<br />
it is limpid, and<br />
likewise passing into the greatest variety of shadings from<br />
white and gray, sometimes from yellow, green, and brown.<br />
The diamond being the hardest 'of all substances, yields<br />
to no file ; scratches all other minerals, and is not touched<br />
by any. This character has become the most important of<br />
the diamond since the late discovery of the amorphous or<br />
compact diamond. It is very frequently tinged light-green,<br />
but more rarely with orange, red, blue, or black ; but' in<br />
setting, these shades disappear, particularly in the smaller<br />
but there are also known diamonds of rose and<br />
diamonds ;
186 A POPULAR TREATISE ON GEMS.<br />
pistachio-nut green colors. The blue color is very rare.<br />
The blue diamond of Mr. Hope, of London, is one of ex-<br />
treme beauty and rarity, and is of immense value; the<br />
yellow diamond in the Museum of Natural History, in<br />
Paris, is likewise very remarkable for its color and size.<br />
The black diamond, which is perfectly black, although<br />
plainly crystallized, occurs most frequently in small bristled<br />
balls, but crystalline points ; the crystals are very small,<br />
grouped together in an irregular manner, and extremely<br />
refractory to the cut ;<br />
it is considered the hardest of all<br />
diamonds. The green diamond is also very rare, but I<br />
have seen some beautiful specimens in the Jardin des<br />
Plantes and in Freiberg, the first in the cabinet of Abbe<br />
Hatty, and the latter in the cabinet of Werner. Its streak<br />
powder is- white or grayish ;<br />
it becomes phosphorescent by<br />
the rays of the sun, and electric by rubbing, which property<br />
it retains for half an hour; its specific gravity is 3'5-3'6 ;<br />
it does not alter before the blowpipe ; it burns, however,<br />
at a high degree of heat, and in atmospheric air with a<br />
bluish flame ; its touch is very cold ; it consists of carbon.<br />
The diamond bears the same name in trade, but is changed<br />
according to its cut; the blackish and brownish diamonds<br />
are called the Savoy diamonds (Diamants Savoyards). The<br />
compact and amorphic diamond was first brought to notice<br />
by the experiments of Mr. Dufrenoy, about five years ago,<br />
as being the transition from the crystallized to the compact<br />
condition, on account of its hardness and specific gravity,<br />
and has become a great article of commerce ; it cuts glass,<br />
scratches quartz and topaz, has a specific gravity of S^V<br />
3'52, and is completely consumed in oxygen gas; it occurs<br />
in kidney-shaped and irregular angular masses, but not in<br />
pebbles ;<br />
the exterior is generally black, sometimes resem-<br />
bling the graphite; somewhat resinous lustre, and fre-<br />
quently its form is very singular, the outside coating being
DIAMOND. 187<br />
black and resinous, the interior forming a crystalline ker.<br />
nel, vitreous and lamellar, like the diamond ;<br />
it is reduced<br />
to powder, and used for polishing and assisting in the cut-<br />
ting of the diamond. The largest specimen of the compact<br />
diamond weighs about 46 carats, and belongs to Mr. Hem-<br />
erdinger ;<br />
and a compact diamond in the Museum of Natu-"<br />
ral History at Paris, weighing about seventeen carats, is<br />
valued at fifteen hundred francs. The original bed of the<br />
diamond is not yet known, and on this point opinions are<br />
much divided. In the East Indies we find it in a conglomerate<br />
of sandstone, consisting of quartz grains, and disintegrated<br />
by the ferruginous sand ; and in the mountain chain<br />
Ralla-Malla, in Hindostan, between 95 and 98 E. L.<br />
Some of the celebrated diamond mines consist of a breccia<br />
from argillaceous slate, quartz, lime, and sandstone; the<br />
boulders and the sand of deserts and rivers yield diamonds<br />
mostly rounded or in a granular form. The richest diamond<br />
mines are those of Roalcorda, at the junction of the<br />
rivers Bimah and Ristna; Golconda, along the shore of<br />
the Pennar, Sumbhulpra, and Bundelkened, in the neigh-<br />
borhood of Pannah, where one thousand laborers are kept<br />
employed. Visapur, Hydrabad, &c., on the island of Bor-<br />
neo, likewise yield diamonds ; and, according to Jameson,<br />
diamonds were found in the Indies in the coal formation.<br />
In Brazil, they were discovered, in 1728, by chance, having<br />
been always thrown aside with the flint and other<br />
refuse of the washings of gold, until an inhabitant, who had<br />
some knowledge of rough diamonds, collected a large num-<br />
ber, and carried them to Portugal, and acquired by their<br />
sale a great fortune. Another, who was informed of the<br />
operations of the first, shared an equally good fortune.<br />
The government's attention was drawn to the matter, and<br />
it was declared, in 1730, that all diamonds found there<br />
belonged to the crown.
188 A POPULAK TREATISE OX GEMS.<br />
Diamonds are found in the talcose chlorite schist, and in<br />
a breccia, consisting of ferruginous clay, quartz pebbles,<br />
sand, and oxide of iron fragments ; and also in a secondary<br />
bed, accompanied by gold, platina, topaz, beryl, chryso-'<br />
beryl, tourmaline, kyanite, amatose, spinelle, corundum,<br />
and garnet. They are found particularly in the valley oi<br />
Sejues, along the rivers Jequetinhonha and Pardo, which<br />
run into .the diamond district. These carry most diamonds<br />
by. The dykes and brooks of the district contain more or<br />
less rich diamonds, which are found there in recent and<br />
older beds. Beyond the diamond district, the diamond is<br />
likewise found in the province of Minas Geraes on the Serro<br />
de St. Antonio, in the Serro Frio, and in the rivers Aboite,<br />
Andaja, da Saneno, da Prata, and several other places,<br />
such as the right bank of the Rio San Francisco, and<br />
Matto Grosso, and in the beds of Rio Pardo and Rio Vel-<br />
has ; in the mines of Riven and Cuithe, and all along the<br />
valley of Peruguado river, in the. province of Bahia, in<br />
some of the tributaries of the Rio Doce, on the banks of<br />
the Cachoine. The rocks in which recently diamonds<br />
have been found consist of the itacolumite, a micaceous<br />
sandstone, accompanied by mrca-schist, accidentally trav-<br />
ersed by quartz veins. This is the prevailing rock in the<br />
Serro de St. Antonio, in which the Jequetinhonha rises in<br />
the Serro da Matta da Corda, on the eastern slope of<br />
which the tributaries of the Rio Francisco rise ;<br />
and in the<br />
diamond district of Tibagy, very rarely in the alluvials of<br />
ancient rocks. The gold, diamonds, and other fine stones,<br />
are always imbedded in the lower part of the alluvium.<br />
Experience -has shown the richest localities to be in Curranlinho,<br />
Datas, Mendanho, Cavallo-Morte, and Caxoeira de<br />
Inferno, Avhere the alluvial soil is from eight to twenty<br />
feet thick, and is composed almost entirely of silicious<br />
sand, strongly colored by argillaceous iron, which forms a
DIAMOND. 189<br />
species of cement of pebbles of quartz, milky quartz, and<br />
itacolumite, which form a coarse pudding-stone, called<br />
casoelho, and which is considered by the diamond-washers<br />
a sure sign of the diamond. Dr. Cliffe, the proprietor of a<br />
diamond mine in Brazil, has given much information on<br />
this subject.<br />
In Russia, the first diamond was discovered in July,<br />
18^9, by Humboldt and Rose, when on their journey to<br />
Siberia, on the west side of the Uralian mountains, in the<br />
gold-washing establishments of Krestowosdwisheaski, belonging<br />
to Count Schuwalow. The locality, in connection<br />
with the other circumstances of the place where the diamond<br />
was found, bears a striking resemblance to the diamond<br />
district of Brazil. The predominating rock of the<br />
spot on the Uralian mountains is a quartzose chlorite, talcose<br />
schist (itacolumite), with an admixture of iron pyrites<br />
and mica, wherein we find beds of red oxide of iron, talcose<br />
schist, limestone, and dolomite. In the valley of Poludenka<br />
and Aedephskoi the diamonds are found among the "debris<br />
of the mountains, accompanied by quartz, itacolumite,<br />
brown hematite, talcose slate, dolomite, chalcedony, ana-<br />
tase, gold, and platina ; it is not yet<br />
decided to what for-<br />
mation this rock originally belongs. The production of<br />
diamonds is twofold; either they are dug out from the<br />
earth, or they are collected in the sand of rivers. If in<br />
the latter way, they are more or less rounded, wedged,<br />
and rubbed off; whereas the former appear coated with an<br />
earthy, pale gray, yellow, or rose-red, rarely with a blue or<br />
green crust. Many valuable mines have been relinquished<br />
in the East Indies since the discovery of diamonds in Bra-<br />
zil. The locality of the finest diamonds is at present in the<br />
neighborhood of Sumbhulpore. Two tribes, called the<br />
Thata and Tora, living in sixteen villages, occupy them-<br />
selves particularly with searching for diamonds, beginning
190 A POPDXAE TEEATISE ON GEMS.<br />
in the month of November, and continuing until the L<br />
mencement of the rainy season, more especially in the bed<br />
of the Mahanudi on its left shore, where some other small<br />
rivers, Maund, Reloo, Eeb, &c., empty into it. Four or<br />
five hundred individuals, consisting of men, women, and<br />
of the<br />
children, are examining continually all the spots<br />
river from Cauderpoor to Longpoor, a distance of about<br />
one hundred and twenty miles, till the stream is imped'ed<br />
by the rocks ;<br />
and likewise all excavations or other cavities<br />
of the beds where any alluvial deposits may be traced.<br />
All their implements consist of a pickaxe (ankova), a board<br />
five feet in length, excavated three inches in the middle,<br />
but provided with its border (daer), and a smaller similar<br />
implement, called by them kootla, both of the shape of a<br />
shovel. The process is very simple : they first dig the<br />
earth with the axe, and let it accumulate in heaps. along<br />
the shore; the women afterwards take it on their large<br />
shovels, and allow the water to run over the earth ; they<br />
then pick the flints and coarse gravel out of it, and re-<br />
moving the residue on smaller shovels, spread it out, and<br />
examine it very carefully, separating from it the diamonds<br />
and grains of gold. Another method pursued in the East<br />
Indies is to surround a small plain where the diamonds are<br />
expected to be found, with a wr all two feet high, under<br />
which water is permitted to run by -several openings ; after<br />
having thrown a good deal of earth within the wall, and<br />
having allowed the water to pass through two or three<br />
times, the larger stones are picked out, the residue dried,<br />
and the diamonds selected as before.<br />
The washing establishments of the diamond in Brazil,<br />
on the Rio<br />
particularly in the celebrated district Tejuco,<br />
San Francisco and its adjoining smaller rivers, are con-<br />
ducted in the following manner :<br />
In order to get at the bottom, or soil of the river, means
DIAMOND. 191<br />
are used for leading the water at a certain spot in a differ-<br />
ent direction, and then that part of the bed of the river is<br />
allowed to dry out, and the sediment consisting of a<br />
conglomerate of .quartz pebbles, kept together by oxide of<br />
iron, is brought to one place for '<br />
washing. It is a large<br />
bench of triangular form, so as to keep from twenty to<br />
thirty negroes busy: in the middle of this bench is a<br />
gutter, with which is connected a trough, inclined some-<br />
what, in order that the water may run down voluntarily,<br />
but so that it may be stopped by putting loam at the end ;<br />
and another gutter with a trough is joined further down.<br />
The negro who has collected in the dry season a large<br />
quantity, of the sediment, is occupied in the rainy season<br />
in putting from fifteen to eighteen pounds at a time into the<br />
trough, spreading it there, and allowing so much water to<br />
run over it, until it runs off quite clear from the lower<br />
trough, but at the same time keeping the trough continu-<br />
ally moving. He then begins to pick out the larger stones<br />
from the earthy part, and afterwards the smaller, until<br />
he comes to grains, which he examines with the greatest<br />
care, on account of the diamonds. As soon as a negro<br />
has found one, he must make it known by clapping his<br />
hands, and the surveyor, who is seated on an elevated<br />
chair, so that f he can oversee the work,<br />
posits it in a dish filled with water,<br />
found during the day are collected. They<br />
takes and de-<br />
in which all those<br />
are then de-<br />
livered over to the superintendent, who counts and weighs<br />
them, and enters the result, with other particulars, in a<br />
book kept for that purpose :<br />
he keeps them in a bag until<br />
he delivers them, which he does twice a week, to the gov-<br />
ernment at Tejuco.<br />
Every superintendent has to live in the neighborhood of<br />
the principal washing-establishments, which were formerly<br />
leased for a certain sum by the government ; but the im-
192 A POPULAR TREATISE ON GEMS.<br />
positions practised were so great, that it took the superintendence<br />
upon its own account in 1722, and has guarded<br />
the diamond districts along their lines by strong sentinels,<br />
who will not allow strangers to pass through .without the<br />
permission of the general superintendent;<br />
and even the<br />
inhabitants, when crossing the line of the diamond districts,<br />
have to procure written permissions from the above au-<br />
thority ; and everybody must, on leaving the district,<br />
submit to a personal and strict examination and search by<br />
the soldiers ; foot-passengers are always arrested by sen-<br />
tinels and spies continually on the alert. St. Antonio de<br />
of the<br />
Tejuco, forty leagues from Villa Rica, is the capital<br />
diamond district, and the seat of the superintendence of<br />
the Junta Diamontina, consisting besides of a confiskal,<br />
two cashiers, one inspector-general, and a book-keeper.<br />
Ail the diamonds procured are delivered up yearly to the<br />
government at Rio Janeiro.<br />
From four to five thousand negroes were engaged in the<br />
1818 but one thousand :<br />
years 1772 to 1775; in the year<br />
among them were the feitores or surveyors, one hundred<br />
in number, in the latter year ; likewise ten superintendents,<br />
whose business it is to conduct the mining department and<br />
the collection of the diamonds.<br />
In order to encourage the negroes, presents of tobacco,<br />
cloth, &c., are awarded, according to the price of the dia-<br />
the one who finds, for instance, an<br />
monds which they find ;<br />
eighth (seventeen carats and two grains) receives his entire<br />
liberty ; they are severely punished for any offence, and if<br />
repeated are not allowed to be at this work. Notwithstanding<br />
the most rigorous regulations and the most watchful<br />
attention of all the officers, the frauds in stolen diamonds<br />
are very considerable ; and it is estimated that the smuggling<br />
amounts to one third of the whole income*. The smugglers,<br />
who are runaway slaves, examine the most remote parts of
DIAMOND. 193<br />
the district, or steal the diamonds at night from the work-<br />
ing establishments ; others, again, who understand it, will<br />
take the stolen diamonds from the negroes, and devise<br />
means of escaping with them, either in the soles of their<br />
boots, or in hollow canes, &c. ; and it is a remarkable feet,<br />
that all diamonds obtained from the smugglers are inva-<br />
riably larger<br />
and more beautiful than those which axe<br />
brought into market by the government. The thieves<br />
practise all manner of tricks and impositions, even in the<br />
presence of the surveyors : for instance, they conceal the<br />
good diamonds, during the washing hours, between the<br />
fingers, the toes, in the ears, in the mouth, or in the hair ;<br />
they also throw them away with other stones, in order to<br />
often even swallow them.<br />
pick them up in the night ; they<br />
The soldier who arrests any smuggler, receives a reward ;<br />
the property of the latter is confiscated, and he is sent to<br />
Angola as a prisoner, for upwards of ten years.<br />
The pure transparent diamond, which is cut in the differ-<br />
ent forms already mentioned, loses generally one third to<br />
one half of its original weight by this operation.<br />
The following table shows the original weight of the<br />
rough diamonds, and that after being cut ;<br />
viz, :<br />
Regent, when rough, weighed 410 carats, and when cut, 136 u /ie carats.<br />
Grand " "<br />
Mogul, 780 1 " "<br />
/.,<br />
279<br />
"<br />
/i<br />
" "<br />
" "<br />
Ko-M-noor,<br />
"<br />
~186/a<br />
82"/16<br />
South " "<br />
" "<br />
"<br />
Star,<br />
254'/a<br />
. 124/i<br />
Nassak, once cut,<br />
89 3 " "<br />
"<br />
/4<br />
78 10 /i<br />
It will be perceived, therefore, that the skill of the dia-<br />
mond-cutter has made great progress in modern times, inasmuch<br />
as the weight of the Ko-hi-noor and South Star<br />
was only reduced to one half of the original weight.<br />
In purchasing rough diamonds, every precaution ought<br />
to be used to prevent getting false diamonds instead of<br />
9
194 A POPULAR TREATISE ON GEMS.<br />
real ones, and faulty ones instead of pure diamonds. The<br />
officers of the Junta Diamontina test the rough stones by<br />
holding them whilst rubbing together, close to the ear, and<br />
listening to the tone produced, which gives them ample<br />
satisfaction of their being genuine, as it is only to be ob-<br />
served in real diamonds. It requires, however, consider-<br />
able practice to distinguish them with accuracy by this test.<br />
Strangers particularly, are imposed upon by the negroes<br />
in Brazil, by purchasing from them gems cut and polished<br />
with the facets, resembling those of the diamond; and<br />
although any one acquainted with the diamond will soon<br />
detect the imposition by the want of specific weight, the<br />
peculiar lustre, fire, and hardness, he requires to be on his<br />
guard. If, however,<br />
the diamond is ascertained to be<br />
genuine, we have to examine particularly its purity, color,<br />
form, and size, these being the qualities by which the price<br />
of a rough diamond is to be determined.<br />
It requires considerable experience to determine from a<br />
of its faults are at the surface<br />
rough diamond whether any<br />
or in the interior, whereby often the diamond, in removing<br />
all its faults, may be diminished to half its size. We often,<br />
however, judge the rough stones by their color ; those<br />
turning towards the green<br />
color are considered to be the<br />
best ; those of a reddish color to be good stones ; the black<br />
color indicates a hard stone ; and we judge a yellowish or<br />
grayish color as making bad diamonds. The natural form<br />
of a diamond, likewise, gives a characteristic to the pur-<br />
chaser of rough stones ;<br />
for a flat, thin, or triangular stone<br />
would lose much in the grinding, and not be so high as to<br />
and likewise we are not sure of the<br />
give it sufficient fire ;<br />
result of the cutting, and the hemitrope crystals are very<br />
difficult to work. The best forms of diamonds for cutting<br />
are the octahedron, which is principally found in the East<br />
Indies, and is called Pint by the diamond-grinders and the<br />
;
DIAMOND. 195<br />
rhombic dodecahedron, which is found principally in Brazil :<br />
cheese-stones is the name given to amorphous diamonds b}<br />
the diamond-grinders.<br />
According to the quality of the diamonds, they are<br />
divided in Sumbhulpur into four classes, which correspond<br />
with the deities of the Hindoos the Bramins, Tschettri,<br />
Wassiers (Bysh), and Tschadrie. The native jewellers are<br />
very expert in estimating the value of these diamonds.<br />
The value of the polished diamonds depends on the fofc<br />
lowing<br />
conditions :<br />
1st. Color. The limpid diamonds command the high-<br />
est price, and twice as much as those that are colored;<br />
the blackish, brownish, yellowish, brown, steel-gray, and<br />
impure bluish ones, stand in no value, and are often rejected<br />
for working.<br />
2d. Purity, Faultlessness, and Transparency. The Diamonds<br />
ought to be, according to the technical terms of<br />
the jewellers, free from ashes, gray spots, rusty or knotty<br />
places, veins, fissures, scratches, feathers, flaws, sand, grains,<br />
and faint yellow or vitreous spots. The Brazilian diamonds<br />
exhibit sometimes, in their interior, designs resembling<br />
mosses, like those of the Mocha stones and agates ; and we<br />
may often observe it in the green diamond ; if a limpid<br />
diamond plays somewhat in the brown* color, it is called<br />
shrugging, and this diminishes its value : paunched, are<br />
those diamonds which are neither pure nor clear.<br />
The transparency and clearness of the diamond are di-<br />
vided into three degrees, viz :<br />
A, of the first water, as in those diamonds which are free<br />
from even the slightest faults, and stand highest in price.<br />
B, of the second water, as in those diamonds which,<br />
although clear and limpid, are marred by some dark spots,<br />
clouds, or flaws.<br />
C, of the third water, as in those diamonds having ?.
196 A POPULAR TREATISE ON GEMS,<br />
t<br />
gray,' brown, yellow, green, Hue, or blackish color ; or<br />
those that are limpid, but are injured by several material<br />
faults.<br />
In order to determine accurately the nature of diamonds,<br />
lose for a mo-<br />
it is well to breathe on them, whereby they<br />
ment their lustre, and the ,eye is then better enabled to<br />
examine them and distinguish their faults. The real diamond<br />
becomes clear much sooner than the false.<br />
3d. The Cut. The perfect and regular cut of the diamond<br />
increases its value considerably; a brilliant, -for in-<br />
stance, of one carat, is worth twice as much as a rough<br />
diamond of equal weight. It depends upon the proportions<br />
of the height to the circumference of the diamond, and<br />
that the planes and facets stand in a regular proportion, for<br />
should this not be the case, the diamond would lose much<br />
of its fire.<br />
the price.<br />
Likewise, the form of the diamond influences<br />
A brilliant is dearer than a rose-diamond, and<br />
this is again dearer than the thick and table-stone. The<br />
facets of the brilliant also influence the price : once cut is a<br />
brilliant that possesses no cross-facets on the lower part of<br />
the stone ;<br />
twice cut, there is one row of facets on the collet<br />
side; thrice cut, the brilliant possesses the facets on the<br />
bizel and collet side, according to the rule of cutting.<br />
The<br />
more rows of facets a brilliant displays, the higher price is<br />
put upon it.<br />
4th. The Size and Weight. The price of a diamond de-<br />
pends considerably upon- its size ; those diamonds which<br />
are of great splendor and size are called Paragons' or Non-<br />
pareils, the Ne Plus Ultra; the less weighty ones are<br />
valued according to their actual weight. The weight em-<br />
ployed in Sumbhulpur is the rutta and masha. Seven rutts<br />
is equal to one mash, and one rutt is equal to two grains.<br />
In Brazil the weight is specified by carats (quilates).<br />
Seventeen and a half quilates are equal to one drachm (oc-
DIAMOND. 197<br />
tava) ; thirty-two vintenes are equal to seventy grains<br />
one carat is equal to four grains.<br />
The price of diamonds is determined in trade by exam-<br />
(graos) ;<br />
ining accurately their character as above stated, and then<br />
the price is fixed ; the weight of the diamond is at first<br />
multiplied by itself, and the sum obtained multiplied again<br />
by the price of one carat. A brilliant, for instance, would<br />
weigh two carats, and on examining its properties, if good,<br />
its price would be found to be forty-four francs. We proceed<br />
in the following manner to get at the full value of the<br />
diamond : 2X2X44 = 176 francs. We do not always, how-<br />
ever, arrive at the correct result. If the brilliants are very<br />
large, and exceed the weight of eight or ten carats, it is<br />
difficult to arrive at a standard. I will endeavor to give<br />
below a table of the prices of the diamond in Holland,<br />
France, England, Germany, and .the United States, as far*<br />
as ascertained, and as near to the actual price current as I<br />
could obtain.<br />
Rough diamonds fit for cutting<br />
francs per carat ; any diamond exceeding the weight of one<br />
are worth ten or twelve<br />
carat is estimated by the square of its weight multiplied<br />
by eleven or twelve francs as the average price.<br />
Brilliants of three grains are in much demand, and are<br />
worth fifty francs per carat. Those of three carats, used<br />
for icentre-pieces in necklaces, are sometimes worth four<br />
hundred francs. Rose-diamonds for mounting, and forty
198 A POPULAR TREATISE ON GEMS.<br />
to the carat, are worth twenty francs the carat ; if r* little<br />
larger, thirty-live francs per carat.<br />
Diamonds unfit for cutting, and used by glass-cutters or<br />
glaziers, are worth from ten to fifteen francs per carat, and<br />
still smaller ones are worth less ; they are now employed<br />
by lithographers for their engravings and etchings.<br />
In 1837, according to Ketot, Pujoux, and Lucas, the<br />
price<br />
of diamonds of the first water was three hundred<br />
francs per carat ;<br />
Diamonds of one 'grain and less,<br />
The double cut, first water,<br />
6 to a grain,<br />
Of two -<br />
grains,<br />
Of three -<br />
grains,<br />
Of one -<br />
carat,<br />
A diamond of 6 grains,<br />
10<br />
12<br />
15<br />
18<br />
and second water, one hundred and fifty,<br />
'*<br />
of 6 carats,<br />
96 francs per carat.<br />
125 "<br />
150 "<br />
170<br />
"<br />
- 200<br />
260-280<br />
( '<br />
- 600<br />
- 1000<br />
- 1400<br />
- 1800<br />
- 2400<br />
- 3500<br />
- 5000<br />
The abqve prices are from Brard's Mineralogie appliquee<br />
aux Arts. .<br />
'<br />
The price of diamonds (in 1855), according to Mr.<br />
Achard,<br />
a celebrated dealer in Paris :<br />
Glass-cutters' diamonds, less than a grain, 50 francs, or $10 00 per carat.<br />
Diamonds to reduce to - -<br />
powder,<br />
12 " 2-50<br />
"<br />
These are the natural diamonds.<br />
Diamond powder for polishing,<br />
Compact diamond, called carbonite,<br />
" in powder,<br />
Diamonds of 1 carat are worth -<br />
"<br />
2 " "<br />
8 francs, or $1 75 per carat.<br />
4-6<br />
"<br />
1 50 "<br />
6 "<br />
1 '50 "<br />
250 francs, or $50 00<br />
800 " 160 00<br />
-<br />
1,500<br />
-<br />
10,000<br />
"<br />
"<br />
SOO'OO<br />
2000 00
DIAMOND. 199<br />
According toBarbot, the present (1858) price current of<br />
diamonds of good quality, and in relation to their weight<br />
and various forms, is the following :<br />
A diamond of 1 carat is worth, per carat, 300 francs, or $60 00<br />
8 grains<br />
240<br />
48 00<br />
210<br />
42 00<br />
recut, 8 to the carat,<br />
200 A POPULAR TREATISE ON GEMS.<br />
A good white and perfect diamond of two carats<br />
weight is worth from - - - - -<br />
f 300 to $350<br />
A 3 carat _______ stone, 500 600<br />
4 " - 900 1000<br />
5 " -_--__- 1000 1200<br />
Spread diamonds, meaning flat stones, so as to display a<br />
large surface, whereby the collet is shorter than the crown,<br />
are generally sold much cheaper ; they do not, however,<br />
display tHeir elements with the brilliancy of a diamond<br />
having two thirds of the collet and one third of the crown<br />
in size.<br />
At a most extensive sale of diamonds, which took place<br />
in the summer of 1837, at the auction of Rundell &<br />
Bridges, London, there were twenty-four lots put up,<br />
which produced the sum of forty-jive thousand eight<br />
Jmndred and eighteen pounds, nearly two hundred and<br />
twenty-nine thousand dollars ! Some of the prices were<br />
as follows : The celebrated Nassak Diamond, which weighs<br />
three hundred and fifty-seven and a half grains, and is of<br />
the purest water, was purchased for thirty-six thousand<br />
dollars. It is. considered to have been sold at a price con-<br />
siderably under its value. A magnificent pair<br />
of brilliant<br />
ear-rings, weighing two hundred twenty-three and a half<br />
grains, formerly the property of Queen Charlotte, were<br />
bought for fifty-five thousand dollars, a price infinitely below<br />
their usually estimated value. A sapphire, seventy-five<br />
and a half carats, set with brilliants for a brooch, two thou-<br />
sand four hundred and sixtySve dollars. Brilliant earrings,<br />
three thousand seven hundred and fifty dollars. A<br />
brilliant necklace, four thousand three hundred dollars.<br />
two thousand three hundred and<br />
Drop emerald ear-rings,<br />
twenty-five dollars. Brilliant ear-rings, four thousand two<br />
hundred and fifty dollars. A Turkish dagger, mounted<br />
with brilliants and rubies, four thousand dollars. A single
DIAMOND. 201<br />
brilliant, eight hundred dollars. A brilliant drop, seventy-<br />
nine and a half grains, five thousand nine hundred dollars.<br />
An oblong brilliant, one hundred fifty-one and a quarter<br />
grains, fourteen thousand dollars. A brilliant necklace,<br />
eight thousand dollars. Brilliant ear-rings, twelve thousand<br />
five hundred dollars. Brilliant necklace, twelve thousand<br />
five hundred dollars. Brilliant drops, formerly belonging<br />
to Marie Antoinette, eight thousand eight hundred ancf<br />
seventy-five dollars. A rose-diamond, eight thousand five<br />
hundred dollars. A brilliant drop, ten thousand five hun-<br />
dred dollars. A round brilliant, seventeen thousand five<br />
hundred dollars. A lozenge brilliant, three thousand five<br />
hundred dollars, &c.<br />
Frauds in diamonds are practised by dealers, and the<br />
purchaser must be guarded. The white spinelle crystal-<br />
lizes also in regular octahedrons, but is not as hard, and is<br />
therefore scratched by the diamond. The angle under<br />
which the light is polarized in either of the other gems is<br />
very different.<br />
On comparison with the prices of those now in market,<br />
it is certain they have much declined, which is partially to<br />
be attributed to the immense stock which has been brought<br />
from their native locality. According to Spix and Martius,<br />
there have been produced in Brazil, from 1772 to 1818,<br />
in the time of the<br />
1,298,037 carats of diamonds that is,<br />
Royal Administration; but that during the Lease, only<br />
1,700,000 carats were produced, which together make<br />
2,998,037 carats, or 1301-J- pounds, thus averaging from<br />
fourteen to fifteen pounds per year ; those brought into<br />
market by contraband being excepted. The value of the<br />
above diamonds (8000 reis per carat), produce'd in Brazil,<br />
amounts to 23,984,276,000 reis, or about 40,000,000 francs.<br />
This sum bears no comparison to the expense of procuring<br />
them, since the government lately paid 1<br />
forty francs fifty
202 A POPULAR TREATISE ON GEMS.<br />
centimes per carat, whereas they only yielded from eight<br />
een to nineteen francs. On this account the administration<br />
at Rio de Janeiro has been induced to lease the mines to<br />
private individuals. Owing to this decrease in the produc-<br />
tion, the number of laborers is reduced. The richest production<br />
was in 1784, when 56,145 carats were washed out ;<br />
and the poorest in 1818, when they procured but 9396<br />
carats. In Brazil, large diamonds are much rarer than in<br />
the East Indies, where they are in general of much better<br />
quality than in Brazil. In the latter country, from 1772 to<br />
1811, they found but thirty-six diamonds weighing upward<br />
of seventeen carats, and from 1812 to 1818, but eightythree<br />
diamonds weighing over eight carats. In the East<br />
Indies, according to Breton, from the year 1804 to 1818,<br />
there were found in Mahanues twenty large diamonds, the<br />
aggregate weight of which amounted to four hundred and<br />
thirty-six carats and one grain. The largest was found in<br />
1809, and weighed six hundred and seventy-two grains,<br />
but was of the third water ; another of three hundred and<br />
eight grains, and another of two hundred and eighty-eight<br />
grains.<br />
As it has already been stated that the artist and amateur<br />
have to be on their guard against imposition in the purchase<br />
of diamonds, it may be well to state that there is the one-<br />
half brilliant, having the form of a brilliant above (the<br />
or another stone<br />
upper pyramid), but no lower pyramid ;<br />
is pasted on by<br />
stone is readily detected when taken out of the mounting.<br />
means of mastic. The character of the<br />
Sapphires, hyacinths, emeralds, and topazes are sometimes<br />
slightly calcined and sold for diamonds. The first<br />
two are heavier than the diamond; they are, however,<br />
.<br />
harder, and possess more fire. The topaz is distinguished<br />
by its property of becoming electric when heated, which<br />
lasts for several hours.
DIAMOND. 203<br />
Rock-crystal is much lighter, but brilliant and hard ; and<br />
the same character is applicable to the strass.<br />
The following list shows the size and weight of the most<br />
interesting diamonds in the possession<br />
of different sover-<br />
eigns.<br />
The largest diamond is in the possession of the Grand<br />
Mogul, and according to Tavernier, resembles in form and<br />
size, half a hen's egg. Its weight is two hundred and<br />
and three sixteenths carats. It was found in<br />
n^ety-seven<br />
1552, in the mine 'of Colore, a short distance to the east of<br />
Golconda, and is valued at 11,723,000 francs. It is cut<br />
as a rose-diamond, and is perfectly limpid, with the excep-<br />
tion of a small flaw at the end o"f the girdle. -<br />
The diamond in the possession of the Rajah "of Mattan,<br />
carats : it<br />
in Borneo, weighs three hundred and sixty-seven<br />
was found on that island." It is of an egg form, has<br />
a cavity towards the thinner end, and is of the first<br />
water.<br />
The Orlow, the diamond belonging formerly to Nadir<br />
Shah, sultan of Persia, and now in possession of the Russian<br />
crown, weighs one hundred ninety-four and three<br />
fourths carats. It is of the first water, without flaws or<br />
faults of any kind. Its form is that of a flattened oval,<br />
about the size of a pigeon's egg it formed the eye of a<br />
Braminian god cut in a pyramidal form ; it is one inch<br />
three lines in diameter, and ten lines high. It was purchased<br />
by the Empress Catharine for about ninety thousand<br />
pounds, cash, and an annuity of four thousand pounds, but<br />
is considered of more value.<br />
The diamond in the treasury of^llio Janeiro, was found<br />
in 1771, at Rio Abaite, by three criminals, who delivered<br />
it to the government, for which they were pardoned. It<br />
weighs one hundred and thirty-eight and a half carats.<br />
The Austrian crown possesses one which weighs one hun-
204 m A POPULAR TREATISE ON GEMS.<br />
dred and thirty-nine and a half carats, and is valued at one<br />
hundred and nine thousand two hundred and fifty pounds.<br />
It is beautiful and well formed, but its color turns towards<br />
the yellow.<br />
There is another belonging to the crown, which was<br />
formerly in the possession of Charles the Bold, of Burgundy,<br />
who lost his all in the battle of Granson. This<br />
diamond was at that time the largest in Europe. A<br />
Swiss soldier, who was the robber thereof, sold it foi^te<br />
crown dollar to a priest ;<br />
and after passin-g through several<br />
hands, it was purchased by Pope Julian II. for twenty<br />
thousand ducats.<br />
The Regent, or Pitt diamond, belonging<br />
to the crown<br />
of France, is said to have been found in Malacca, and was<br />
purchased by Mr. Pitt, then governor of Bencoolen, in<br />
Sumatra, and sold by him to the Regent, duke of Orleans,<br />
by whom it was placed among the crown-jewels of France.<br />
It weighs one hundred and thirty-six and three quarters<br />
carats ; is cut in the form of a brilliant, and is of the first<br />
water, being absolutely faultless. When rough, it weighed<br />
four hundred and ten carats, required two years' labor in<br />
cutting, and is worth, according to the value put 'by the<br />
commission of jewellers, in 1791, twelve millions of livres.<br />
It was much admired in the exhibition of Paris, in 1855,<br />
among the crown-jewels of France. .<br />
The Sancy, belonging to the crown of France, is one of<br />
the celebrated diamonds, although not as large as the last<br />
mentioned, still a very beautiful stone ; it is of a pear-shape,<br />
is cut as a double rose-diamond of an oblong figure, and<br />
weighs fifty-six and a %lf carats (thirty-three and twelve<br />
sixteenths, according to Barbot), and it cost 600,000 livres,<br />
but is now valued at double that sum.<br />
A very curious history is attached to this stone, which<br />
may not be uninteresting to the reader, for its peregrina-
DIAMOND. 205<br />
tions are wonderful and are well worth relating.<br />
At first<br />
it was seen glistening in the casket of Charles the Bold,<br />
the last duke of Burgundy, who lost it in the battle of<br />
Granson ; it was found by a Swiss, who sold it to a priest<br />
for two francs, he resold it for three francs ; it is then lost<br />
eight of until in the year 1589, King Anthony, of Portu-'<br />
gal, pledged the same among other stones to M. de Sancy,<br />
then Treasurer of the King of France, who retained it by<br />
paying 100,000 francs for it. Henry III., after a lapse of<br />
time, borrowed it for the purpose of pledging it to the<br />
S \yiss government, but the servant that was to* convey it<br />
to that country disappeared, and was not heard of for a<br />
long time; at last it was discovered that the messenger<br />
but the faithful servant rather<br />
was assassinated by thieves ;<br />
than deliver the jewel to the thieves preferred swallowing<br />
it. .The spot where the body was interred was discovered ;<br />
being disinterred, on dissecting the stomach the diamond<br />
was found. The Baron de Sancy disposed of it to James<br />
II., while at St. Germains, and from him it fell into the<br />
hands of Louis XIV. for 625,000 francs, and has ever since<br />
been the property of the* crown of France. The same<br />
stone was lost in 1792, with the greater part of the other<br />
jewels: it "was founcj. again by the police in the Champs-<br />
Elysees, through an anonymous letter.<br />
*The Regent, the blue diamond, the celebrated onyx<br />
known by the name of Abbe Sugen's communion-cup, with<br />
other diamonds to the value of several millions of francs,<br />
were then stolen, and but few of them recovered.<br />
The blue diamond of the crown-jewels of France, is of<br />
a rich sky-blue color, and weighs sixty-seven and one eighth<br />
carats; it was valued at 3,000,000 francs, but was stolen<br />
among the other jewels, in 1792, and not recovered. It is<br />
said, however, that it was sold in 1835, by an agent of the<br />
Bourbon family, to a purveyor of the Emperor of Russia,
206 A POPULAR TREATISE ON GEMS.<br />
for the sum of 500,000 silver roubles ;<br />
since which time it<br />
has been in the hands of the Princess Paul Demidoff.<br />
Russia is said to be the richest country for diamonds;<br />
her crowns are of immense value ; that of Ivan Alexiowitch<br />
contained 881 brilliants ; that of Peter the Great, 847 ; that<br />
of Catharine, 2536, and the present emperor has purchased<br />
for his crown an immense amount of brilliants.<br />
The Shah-is another of the great diamonds belonging to<br />
the Russian crown ;<br />
it is an irregular prism, of fine water,<br />
and weighs ninety-three carats; it belonged formerly to<br />
the Emperor of Persia, and then to Nadir-Shah, "and was<br />
stolen by the revolting soldiers.<br />
The Polar Star belongs to the Princess Youssoupoff, is<br />
cut into a brilliant, and weighs forty carats.<br />
The Prince Esterhazy, as colonel of a fine regiment in<br />
the service of Austria, Wears, in his uniform of state, a tliamond<br />
valued at twelve millions of francs.<br />
The Pacha of Egypt has a diamond cut in facets, which<br />
weighs forty carats, and cost 700,00'0 francs.<br />
The Piggot weighs eighty-two and a half carats ; is not<br />
very fine ; was sold by lottery, in 1801, for 750,000 francs,<br />
and belonged, in 1818, to the jewellers Rundell & Bridges.<br />
The Nassak belonged formerly to* the East India Com-<br />
pany; weighs eighty-nine and three quarters carats; has<br />
since been recut by order of the Marquis of Westminster;<br />
weighs at present but seventy-eight and five eighths carats,<br />
and is valued at 800,000 francs.<br />
The Holland Diamond weighs thirty-six carats, and is<br />
valued at 260,000 francs.<br />
The Hope Diamond, which weighs forty-four and one<br />
eighth carats, is of a beautiful color like* sapphire ;<br />
is sus-<br />
pected of being the same stone which was stolen among the<br />
French jewels, in 1792. Owing to its beauty it was purchased<br />
for 450,000 francs, but is worth more.-
DIAMOND. 207<br />
The Dresden Treasury has a beautiful green diamond,<br />
like emerald, which weighs thirty-one and one quarter<br />
carats.<br />
The value of the crown-jewels of France, has always<br />
been 29,000,000 franco; among them are comprised<br />
Diamonds 16,730,203 francs.<br />
"<br />
Pearls (506 in number) 996,700<br />
Colored Stones<br />
230Kubies ,<br />
134 Sapphires<br />
-150 Emeralds...<br />
71 Topazes.<br />
3 Amethysts (Oriental)<br />
8 Syrian Garnets<br />
8 Other fine stones .-<br />
360,604<br />
Mounted jewelry 5,834,490<br />
Ornaments and trinkets 5,144,300<br />
Total 29,066,487<br />
The great treasures which were, stolen on the 17th September,<br />
1792, and not recovered, contained over 1000<br />
carats of IHlliants and roses of various sizes and qualities.<br />
In 1810 the Emperor Napoleon L, after purchasing over<br />
the Continent all the diamonds and jewels which were<br />
formerly stolen from the treasury, had another inventory<br />
made out.<br />
A very black diamond, which belonged to Mr. Papst,<br />
who sold it to Louis XV 111. for 24,000 francs; it is of<br />
dark-brown color, but a fine lustre. It came from the<br />
but it is not known what has become<br />
collection of Dagni ;<br />
of it.<br />
A fine rose-diamond of fifteen carats, in the possession<br />
of Prince Rioria, at Naples, in 1830.<br />
Mr. Halphen owned a diamond, in 1838, of twenty-two<br />
and one half carats weight, of a magnificent and rare<br />
water.<br />
"
208 A POPULAR TREATISE ON GEMS.<br />
The Nizam belonging to the King of Golconda,<br />
is a<br />
magnificent rough diamond ; it weighs 340 carats, and is<br />
valued at 5,000,000 francs.<br />
There are two rough diamonds, belonging to the King<br />
of Portugal, one of which weighs 215 carats; they were<br />
found in the river Abayte, which runs 'through the Province<br />
of Minas Geraes, in Brazil.<br />
A magnificent pyramidal cut diamond, in Brazil, is<br />
valued at 872,000 francs.<br />
A rough diamond, found in the river Abatio in Brazil, is<br />
in the possession of the Prince Regent of Portugal, which<br />
weighs an, ounce Troy.<br />
The two large diamonds belonging to the Shah of Persia<br />
have already been mentioned in the first part, with accom-<br />
panying figures.<br />
The Turkish crown has two very large diamonds ; one<br />
of eighty-four carats, and the other of one hundred and<br />
forty-seven carats. The latter is valued at eighty thousand<br />
ducats.<br />
One found in Brazil, in 1780, weighs seventy-two carats<br />
and three fourths of a grain. Another, found in 1803,<br />
weighs seventy carats. They are both at Rio Janeiro.<br />
The largest of all known diamonds is said to be in the<br />
possession of the King of Portugal. It was found in Bra-<br />
zil, in the diamond district, and is as yet in its rough state.<br />
It is of the size of a chicken's egg, weighing one thousand<br />
six hundred and eighty carats (above eleven ounces), and<br />
is estimated in value at fifty-seven million pounds sterling.<br />
It is now the general opinion of jewellers and mineralogists<br />
that this is a white topaz.<br />
The Ioli4-noor, of which there is an exact representation<br />
on the frontispiece of this work, in its present form, belongs<br />
to the Queen of England; it is translated as the Mountain<br />
of Light, and is a very remarkable gem, both for its size as
DIAMOXD. 209<br />
well as its history. It belonged formerly to the Grand<br />
Mogul, from whom it passed<br />
into the hands of the sever- '<br />
eigns of Cabal. Runjeet Sing, the king of Lahore, became<br />
possessed of it in 1813, after a victorious war against<br />
the Shah Shuja. At the death of Runjeet Sing, t*he East<br />
India Company took possession of his estates, and this relic<br />
fell into their hands, and by the latter was presented to<br />
the Queen of England. Its original weight was one hun-<br />
dred and eighty-six carats; it was of an elongated form,<br />
which led to the supposition that i^is a part of an octahe-<br />
dral crystal ; this opinion has been repeatedly expressed,<br />
and more particularly by Mr. Tennant, who believes it to<br />
be a fragment of the Grand Mogul's diamond described by .<br />
Tavernier. Its awkward shape and bad polish induced the<br />
queen to have it recut, which was done by Mr. Gaword,<br />
who gave the Koh-i-noor the form of the Regent Diamond,<br />
and lost thereby nearly one third of its original weight.<br />
It is now a beautiful diamond, and is valued at two millions<br />
of pounds sterling.<br />
The Star of the South, a Brazilian 'diamond, found in<br />
July, 1853, is at the present day the largest in Europe,<br />
coming from Brazil. It belongs to Mr. Halphen, a private<br />
gentleman, and weighs two hundred fifty-four and a half<br />
carats ; as a crystal', was a dodecahedron ; it has a specific<br />
gravity of 3*529. On account of a deep cavity of an octa-<br />
hedric form, by which it appears to have been attached, at<br />
a previous stage, to another crystal, it is ascertained by the<br />
French lapidaries that "this diamond will lose nearly half its<br />
weight, so that after being cut and faceted, it will weigh<br />
about one hundred and twenty-five carats, but will still<br />
rank as a princely diamond. It was found by a negress<br />
employed in the mines of Begagem, one of the diamond<br />
districts in the province of Minas Geraes.<br />
Another large Brazilian diamond was found in the river
210 A POPULAR TREATISE ON GEMS.<br />
Abaite, and is said to weigh about one hundred and twenty<br />
carats.<br />
The Nassdk diamond belongs to the East India Com-<br />
pany, and weighs eighty-nine carats. A beautiful green<br />
diamond is shown in the royal collection (griine gewolbe),<br />
weighing forty-eight carats. *<br />
Among the American diamonds may be mentioned one<br />
in the possession of Capt. Dewey, having been found in<br />
Virginia, and a perfect crystal a rhomboidal dodecahe-<br />
dron, with curved faces, of greenish-white color, and per-<br />
fectly transparent weighing about twenty-five carats. It<br />
reflects strongly the light, and has a brilliant adamantine<br />
lustre. Smaller diamonds have been found in Alabama,<br />
'three of which belong to Mr. Barnett Phillips of Philadel-<br />
phia, weighing one,two, and three carats respectively, and<br />
likewise perfect octahedrons. In Rutherford County,<br />
North Carolina, a 'diamond of one and a half carats was in<br />
the possession of Mr. T. G. Glemson. In Hall County,<br />
Georgia, diamonds have been found several times ;<br />
in Cali-<br />
fornia some diamonds are said to have been found.<br />
The black diamond, which has lately been found in<br />
Mexico, in the Sierra Madre, is also attracting the attention<br />
of lapidaries, being harder th#n any other diamond.<br />
Description of the Crown-Jewels of Queen Victoria Z,<br />
worn at Tier Coronation, 28th June, 1838.<br />
The crown in which her majesty "appeared at the ceremony<br />
of the coronation was made by Messrs. Rundell &<br />
Bridges. It is exceedingly costly and elegant"; the design<br />
is much more tasty than that of the crown of George IV.<br />
and William IV., which has been broken up. The old<br />
crown, made for the former of these monarchs, weighed<br />
upwards of seven pounds, and was much too large for the
. DIAMOND.<br />
211<br />
head of he? present majesty. The new crown weighs little<br />
more than three pounds. It is composed of hoops of silver,<br />
the<br />
inclosing a cap of deep purple, or rather blue, velvet ;<br />
hoops are completely covered with precious<br />
mounted with a bah 1<br />
stones, sur-<br />
, covered with small diamonds, and<br />
having a Maltese cross of brilliants on the top<br />
of it.<br />
The cross has in its centre a splendid sapphire ;<br />
the rim<br />
of the crown is clustered with brilliants, and ornamented<br />
with fleurs-de'-lis and Maltese crosses equally rich. In the<br />
front of the Maltese cross which is hi front of the crown is<br />
the enormous heart-shaped* ruby, once worn by the chival-<br />
rous Edward the Black Prince, but now destined to adorn<br />
the head of a virgin queen. Beneath this, in a circular<br />
rim, is an immense oblong sapphire. There are many<br />
other precious gems, emeralds, rubies, and sapphires, and<br />
saveral small clusters of drop pearls. The lower part of<br />
the crown is surrounded with ermine. It is, upon the<br />
whole, a most dazzling and splendid crown, and does infi-<br />
nite credit to those by whom it has been designed and put<br />
together. Her majesty has expressed herself highly pleased<br />
with it.<br />
The following is an estimate of the value of the 'jewels:<br />
20 diamonds round the circle, 1500 each "..... 30,000<br />
2 large centre diamonds, 2000 each 4,000<br />
54 smaller diamonds placed at the angles of the former. . . 100<br />
4 crosses, each composed of 25 diamonds 12,000<br />
4 large diamonds on the top's of the crosses 40,000<br />
18 diamonds contained in the fleur-de-lis 10,000<br />
18 smaller diamonds contained in the same 2,000<br />
Pearls r diamonds, &c., on the arches and crosses 10,000<br />
141 diamonds on the mound 500<br />
26 diamonds on the upper cross .'.... 3,000<br />
2 circles of pearls about the rim 800<br />
111,000<br />
The following list of jewelry exhibited at the London
212 A POPULAR TREATISE ON GEMS.<br />
Industrial Exhibition, in 1851, by some French*and English<br />
manufacturers, comprises but a small part of the im-<br />
mensely valuable treasures therein collected : The Queen<br />
of Spain allowed the manufacturer, Mr. G. Lemonnier, of<br />
The first consisted<br />
Paris, to show two sets of her jewels.<br />
of a diamond necklace, in the form of a ribbon, interlaced<br />
with foliage of emeralds; the stomacher and shoulder<br />
knots, from which were suspended very large emeralds,<br />
with clusters of brilliants. A bouquet was formed of lilies<br />
of brilliants, the leaves of emeralds, and ribbons of brilliants<br />
with pendants of pearls. The ci'own was in the same style,<br />
with aiguillettes in the form of flowers, having stamens in<br />
pearls. The bracelet was likewise a ribbon of brilliants,<br />
interlaced with emeralds. Another set of jewels, made<br />
entirely of diamonds and sapphires ; the crown, composed<br />
in the heraldic style, held in the centre of diamond flowers<br />
a large sapphire ; and a stomacher and necklace, with a<br />
wreath of brilliants and sapphire centres, were all scrupulously<br />
matched, and attracted the attention of thousands of<br />
spectators while the exhibition lasted.<br />
The Russian jewellers, Messrs. Jahn & Bolin, of St. Petersburgh,<br />
exhibited a sparkling diadem, containing 11<br />
very beautiful opals, 67 rubies, 1811 brilliants, and 1712<br />
roses. A bracelet of turquoises and diamonds, and a<br />
brooch in the shape of a knob, composed of 750 turquoises,<br />
with a pair of ear-rings of small turquoises, 709 in number.<br />
The English jewellers, Messrs. Hunt and Koskell, ex-<br />
hibited such a profusion of gems, valued at about two hun-<br />
dred and fifty thousand pounds sterling, that it would re-<br />
quire a lengthy description to give but a faint idea of them<br />
from the rough diamonds of all sizes, by the hundreds,<br />
to the most exquisite cut and polished gems. A bouquet<br />
of diamonds, which was as rich as it was elegant, was made<br />
so as to be entirely taken to pieces, even to the petals of
DIAMOND. 213<br />
the flowers, for the purpose of cleaning, and for forming<br />
into seven broaches. They had some particularly beautiful<br />
bracelets : one in emeralds and diamonds ; another in opal<br />
and emerald, with white enamel.<br />
Messrs. R. & S. Garrard & Co., of London, made a sina-<br />
iiar exhibition of gems and pearls, with a profusion of bril-<br />
liants and rubies, which would occupy a lull page to<br />
describe.<br />
In the collection of Mr. Herz, in London, both in the<br />
London Exhibition exhibited by Mr. Thistlethwayte as<br />
well as in his private residence, I examined a very costly<br />
and unique collection of gems. The diamonds he possesses<br />
are of every shade and color, such as I have only seen in<br />
the celebrated Wernerian cabinet at Freiberg, and Abbe<br />
Haiiy's, at the Jardin des Plantes, in Paris, where they<br />
were in their natural state, while those of Mr. Herz are<br />
cut, and many of them set. He had a bouquet of brilliants<br />
and rubies, valued at four thousand five hundred pounds<br />
sterling, quite magnificently set ; a bracelet of splendid<br />
white and large diamonds, and in the centre a yellow bril-<br />
liant of five carats weight, -which he valued at five thousand<br />
pounds sterling.<br />
Messrs. Blogg & Martin, the diamond brokers of Lon-<br />
don, kindly opened their treasures to me, and my eyes<br />
were dazzled by three bags, weighing about five pounds<br />
.each, of diamonds ; most of them cut in the East Indies, and<br />
weighing from ten to tw'enty carats each. They were not<br />
put in market, but kept as reserve, and the value of that lot<br />
could not have been less than half a million pounds sterling.<br />
I beheld many unique curiosities in hemitrope crystals and<br />
made diamonds ; many thousand carats of rough crys-<br />
tals of diamonds, from one grain to twenty carats, all as-<br />
sorted, in packages, besides the immense valuable supply of<br />
perfect rubies of ten carats and upward. The scarcity ot
214 A POPULAR TREATISE ON GEMS.<br />
these gems in general, and the high price at which the ru-<br />
bies were tlien sold in market, formed a very singular con-<br />
trast while viewing so large a stock in one establishment.<br />
I only recollect from memory what I saw in 1851, at<br />
Messrs. Blogg & Martin's ; the sight of so many valuable<br />
gems had, however, made a lasting impression* on me.<br />
CORUNDUM.<br />
The abo.ve name was applied to a different species from<br />
that of sapphire, but these terms are now generally ac-<br />
knowledged to be synonymous ;<br />
not so, however, the em-<br />
ery, which does not belong to this species.<br />
Both occur in rhomboids ; often, too, in crystals of sec-<br />
ondary* form. They scratch all other gems except the dia-<br />
mond ; their streak and powder are white, and the specific<br />
gravity is 3*9-4 ; they acquire electricity by rubbing, which<br />
is retained for several hours ; they are not fusible before<br />
the blowpipe ;<br />
with difficulty, by means of borax, they form<br />
a clear, limpid glass ; acids have no eifect on them ; their<br />
chemical constituents are alumine, silica, and oxide of iron.<br />
SAPPHIRE.<br />
This name is derived probably from the Hebrew, as it is<br />
often mentioned in the Bible. It is not certain whether'<br />
the ancients were acquainted with the blue variety only<br />
of this gem, and were ignorant of other blue stones, such<br />
as lazulite, fluor spar, &c. It was not used by them as a<br />
gem, probably on account of the difficulty of working it ;<br />
but as a medicine, many peculiar virtues were ascribed to<br />
it. This species has hitherto been usually divided accord-<br />
ing to its different colors. The name of ruby has reference<br />
to a red color, and was applied by the ancients to the car-
SAPPHIRE. .<br />
215<br />
buncle. Sapphire oc
216 A POPULAR TREATISE ON GEMS.<br />
tre, but it occurs likewise much larger, and is seldom less<br />
free from faults than any other species of sapphire.<br />
6th. Oriental aquamarine; greenish blue, pure and<br />
transparent, possessing a higher lustre and greater hardness<br />
than the common aquamarine.<br />
7th. Oriental chrysolite, or peridote; yellowish-green,<br />
resembling in color the chrysoberyl, but may be distin-<br />
guished from it by its higher lustre.<br />
8th. Oriental emerald ; green, more or less dark, inclin-<br />
ing to yellow ;<br />
it does not equal in color the real emerald,<br />
but possesses a higher lustre, and is at the same time very<br />
rare.<br />
The sapphires which sometimes display a peculiar play<br />
of light are divided into<br />
1st. Star sapphire (asteria, opalescent, or chatoyant sapphire).<br />
Some translucent sapphires display, if held before<br />
the sun, or a burning taper, a white light running in six<br />
rays, resembling three white planes, or stripes crossing<br />
themselves at one point. This property is thus visible<br />
when the sapphire is cut convex (or caboehon), and when<br />
the principal axis of the crystal stands perpendicular to the<br />
base of the convex cut stone ; these star sapphires are either<br />
called ruby-asteria, sapphire-asteria, or topaz-asteria, ac-<br />
cordirfg to the color they bear.<br />
2d. Girasol sapphire, Oriental girasol, sunstone sapphire,<br />
or ruby cat's-eye, have a yellowish, reddish, or bluish shine,<br />
or reflection of light, generally of a lighter color than the<br />
stone itself, displayed when moved or turned on the convex<br />
surface.<br />
Sapphire is composed of pure alumina ;<br />
the opaque con-<br />
tains about one per cent, oxide of iron and one per cent,<br />
silica ; before the blowpipe it is unaltered ; fuses with bo-<br />
rax and salt of phosphorus, but is not attacked by the<br />
strongest mineral acids ; friction excites electricity,<br />
and in
SAPPHIRE. .217.<br />
the polished specimens the electrical attraction continues<br />
for a considerable length of time. The perfect and color-<br />
less Fapphire has a brilliant lustre, so that the same may be<br />
confounded with the diamond ; its hardness is inferior to<br />
the latter. The specific gravity of the blue sapphire- is<br />
3'9V9 ; of the ruby, 3'909 ; of the green (Oriental emerald),<br />
3-P49; of the violet (amethyst), 3'921.<br />
The sapphire was well known to the ancients. Pliny<br />
gave a description of the star* sapphire, under the naine<br />
of asteria, The sapphire possesses the double refraction<br />
in an indifferent degree, and its fracture is unequal and<br />
conchoidal. The finest ruby sapphire occurs in the Ca-<br />
pelan mountains, near Syrian, a city of Pegu,<br />
in the<br />
kingdom of Ava ; also in the sand of the Expaillie river,<br />
in Auvergne. Blue sapphires are brought from Ceylon.<br />
Large masses of blue sapphire, of opaque color, have been<br />
found in North Carolina, as well as some isolated crystals<br />
in Buncombe County, North Carolina; but there are many<br />
more localities in the United States, such as New Jersey,<br />
New York, and Connecticut. Sapphires are mostly found<br />
in the sands of rivers, or in boulders, with garnets, zircons,<br />
kyanite, and in basalt. It has been observed that the blue<br />
sapphires are frequent in Ceylon, but not the rubies, and<br />
that in Pegu it is the reverse. The most celebrated mines<br />
of sapphire are at Mo-gaot and Kyat-Pyan, five days' jour-<br />
ney from Ava. The Boa, or -Emperor of the Birmans, re-<br />
tains all the larger sapphires.<br />
For cutting a sapphire an iron mill is used, and for pol-<br />
ishing, a copper mill, or one made of alloy of lead and tin,<br />
to which a horizontal motion is given by ajrery simple machinery<br />
; its surface is charged with diamond powder and<br />
oil, or with fine emery and water. A thick peg or gauge<br />
of wood, pierced with small holes in all directions, is set<br />
close to the mill. The<br />
upright on the lapidary's bench,<br />
10
218 A POPULAR TREATISE ON GEMS.<br />
stone, being placed on the surface of the mill, and the op-<br />
posite end of the stick to which it is cemented being inserted<br />
in one of the holes of the gauge, the mill is put in<br />
motion by turning a winch, and the stone kept steady<br />
on it.<br />
When the stone has all the facets, the cutting mill is<br />
taken out and replaced by one of brass, on which the pol-<br />
and rotten-<br />
ishing is performed by means of fine emery<br />
stone, in the same manner as before. A good judgment is<br />
required in determining the form and proportions best<br />
adapted to set off any particular stone to the best advantage.<br />
If the color is full and rich, its transparency perfect,<br />
and its refractive power considerable, the best form to give<br />
it is the brilliant. If, on the contrary, the color is dilute,<br />
the most advantageous method of cutting it is, to cut the<br />
table side (pavilion) brilliant fashion, and the collet side<br />
(culasse) in steps ; by this means the table itself will be left<br />
dark, while all the light reflected from the steps<br />
under side of the stone will be thrown up into the facets,<br />
. !<br />
on the<br />
by which the table is surrounded. The French lapidaries<br />
cut the most perfect sapphires in a square or octagon form,<br />
with a single delicate -step between the table and the<br />
girdle, and three or four steps between the girdle<br />
collet.<br />
and the<br />
If the sapphires possess a varying chatoyant lustre, or<br />
are of a small size, their form is always hemispherical or<br />
elliptical, without any flat facets; the flatter the ellipse<br />
the more the varying lustre is diffused over the surface of<br />
the stone ;<br />
whereas with a high ellipse it is condensed on a<br />
single spot.<br />
In setting samphires we always use foil answering to their<br />
color. The ruby is set with a reddish gold foil, or a foil<br />
of copper or red glass ;<br />
the blue sapphire with a silver foil,<br />
or blue-colored foil, or with feathers of blue ducks, pigeons,
SAPPHIRE. 219<br />
or peacocks ; and the water sapphire in a black back : but<br />
all perfectly pure sapphires are set d jour.<br />
Many sapphires may be deprived of their specks by a<br />
careful calcination in a crucible filled with ashes or clay,<br />
and they assume then a more agreeable and purer color<br />
and greater transparency.<br />
Sapphires are very favorite gems, and are extensively<br />
used by jewellers for setting in pins, rings, &c. In China,<br />
the ladies'' slippers are mounted with rubies.<br />
The blue sapphires have 'of late been employed as lenses<br />
for microscopes with great success. According to Brews-<br />
ter, it is, for its refracting power, second only to the diamond,<br />
and superior to all other gems. A new use has<br />
lately been made of the sapphire for drawing wires it<br />
being cut in the form of a wedge, through which, by means<br />
of a diamond-point, a circular hole is drilled and then fast-<br />
ened on a brass plate; the wire is drawn through the<br />
smaller aperture of the sapphire towards the wider, by<br />
which process it is reduced to a thinness never otherwise<br />
attained.<br />
The price of sapphires is very relative, but their proportional<br />
value is next to that of the diamond. The Oriental<br />
ruby stands highest in value, and when perfect, and ex-<br />
ceeding three carats, is generally as dear as a diamond of<br />
equal weight and quality. After the ruby, blue sapphire<br />
and as this is not so rare, and occurs<br />
stands next in value ;<br />
in large specimens, it is not so high in price. Some put<br />
the price of the blue sapphire equal to that of the colored<br />
diamonds ; others put the price at half that of a brilliant<br />
under similar circumstances. Sometimes the value is fixed<br />
by multiplying half the price of a sapphire weighing a carat,<br />
with the square of its weight. It is therefore yery difficult<br />
to come at an exact price-current, and the following aver-<br />
age prices come nearest to their commercial value :
220 A POPTJLAK TREATISE ON GEMS.<br />
KUBY.<br />
Of 1 grain weight<br />
2<br />
" "<br />
3<br />
" "<br />
"<br />
1 carat<br />
2 " "<br />
3<br />
"<br />
:<br />
'.<br />
2 francs.<br />
5 "<br />
12<br />
"<br />
20 "<br />
60<br />
"<br />
150<br />
"<br />
4 " " 250<br />
"<br />
5<br />
" "<br />
"<br />
..., '. 350<br />
BLUE SAPPHIRE.<br />
1 carat 10 francs.<br />
2<br />
" 20<br />
"<br />
3<br />
4<br />
" 30<br />
45<br />
"<br />
"<br />
5<br />
" 60<br />
"<br />
6 " 80 "<br />
8 100 "<br />
10<br />
"<br />
Smaller stones 8 to 1 carat are worth.<br />
12tol.<br />
200<br />
8<br />
"<br />
"<br />
" " "<br />
16 to 24<br />
" "<br />
to 1<br />
6<br />
4<br />
"<br />
"<br />
In order to show the various prices of rubies, we cite<br />
the sale at auction of the Marquis de Dree's collection, at<br />
Paris<br />
For a cherry-red Euby of. 2 carats, 1000 francs.<br />
For a darker Euby of 11<br />
"<br />
400 u<br />
For a bluish-red Euby<br />
21<br />
"<br />
1400 ".<br />
For a lighter Euby 3 "<br />
1200<br />
" .<br />
For a blue<br />
"<br />
Sapphire<br />
6<br />
1760<br />
"<br />
For an indigo-blue Sapphire<br />
6*<br />
"<br />
1500<br />
"<br />
For a light-blue Sapphire 4 "<br />
123 "<br />
For a white Sapphire<br />
41<br />
"<br />
400 "<br />
For an Oriental Amethyst<br />
11<br />
"<br />
400 "<br />
For a fine yellow Topaz 61 ". 620<br />
"<br />
For a<br />
"<br />
lighter Topaz<br />
6*<br />
71<br />
"<br />
There are numerous faults and defects to which sapphiiv<br />
are subject, and which always influence their price, such as<br />
clouds, milky or semi-transparent spocks, like chalcedony,
SAPPHIRE. 221<br />
white stripes, fissures or knots, &c. The sapphire, partic-<br />
ularly the red and blue varieties, being great favorites in<br />
commerce, are often imitated, not only by means of other<br />
colored gems resembling them, but also by substituting<br />
pastes. .Instead of ruby, we sometimes get the spinelle,<br />
garnet, hyacinth, red quartz, calcined amethyst, red-burnt<br />
Brazilian topaz, red tourmaline ; and instead of the blue<br />
sapphire, we get the disthene, kyanite, and the cordierite,<br />
hardness is the best test.<br />
NOTICE OF SOME LARGE SAPPHIRES.<br />
Tavernier describes two large rubies said to have be-<br />
longed to the King of Visapur, one of which weighed fifty<br />
and three quarters carats, and the other seventeen and a half<br />
carats. The first was valued at sixty thousand francs,<br />
the other at seventy-four thousand five hundred and thirty<br />
francs.<br />
Th'e prettiest sapphire at present in the Imperial Museum<br />
of France, in Paris, is without fault or defect ; it weighs<br />
132 T 1<br />
g -<br />
carats, and is estimated at 100,000 francs. This<br />
sapphire was found in Bengal by a poor man who dealt in<br />
wooden spoons. It belonged afterwards to the mercantile<br />
house of Rospoli, in Rome, who sold it to a German prince ;<br />
he again sold it to the jeweller Ferret, of Paris, for 1 70,000<br />
francs.<br />
Two great sapphires belonging to Miss Burnett Coutts,<br />
of London, and valued at 750,000 francs, were much ad-<br />
mired at the Paris exhibition in 1855.<br />
The crown-jewels of France contain about 1 50 sapphires,<br />
of an aggregate weight of 350 carats, and are valued at<br />
600,000 francs.<br />
Several sapphires with engravings are seen in Rome,<br />
such as Hercules ;<br />
in Turin, in the collection of Genevasio,
222 A POPULAR TREATISE ON GEMS.<br />
of a Tiberius' head, on white sapphire ;<br />
in St. Petersburg,<br />
and in the French museum.<br />
Wahls quotes a ruby of 436 carats and Furetiere saw a<br />
;<br />
ruby in Paris of 240 carats ; and Tavernier quotes a ruby<br />
of half the size of an egg, with the engraving of Scheik<br />
Sephy.<br />
The King of Aracan possesses a crystal of blue sapphire<br />
and Sir Abram Hume possesses a<br />
of an inch in diameter ;<br />
distinct crystal of three inches in length.<br />
The star sapphire on the frontispiece, was formerly in the<br />
cabinet of Mr. Gilmore in Baltimore.<br />
The large blue sapphire in Hunt & Roskell's case at<br />
the London Exhibition, was extremely beautiful, and the<br />
largest I ever saw.<br />
The ruby-sapphire of the East India Company, in Lon-<br />
don, is certainly the largest in the world.<br />
In the collection of Messrs. R. & S. Garrard & Co., in<br />
the London Exhibition, rubies were in great profusion<br />
mostly set with brilliants and pearls.<br />
The price of rubies depends upon fineness and color;<br />
they are sold in the United States at from three to twenty<br />
dollars per carat.<br />
A fine ruby is worth about the same price as a one carat<br />
and a two carat stone, if perfect, is worth more<br />
diamond ;<br />
than a two carat diamond.<br />
The King of Pegu and the monarchs of Siam monopolize<br />
the fine rubies, as the sovereigns of the peninsula of<br />
India have done the diamonds.<br />
The finest ruby in the world is in the possession of the<br />
first ; its purity has passed into a proverb, and its worth,<br />
when compared with gold, is inestimable.<br />
The Subah of the Deccan is also in possession of a pro-<br />
digiously fine one, a full inch in diameter.<br />
The Empress Catharine, of Russia, possessed one ruby
CORUNDUM. 223<br />
of the size of a pigeon's egg, presented to her by Gustave<br />
in., king of Sweden, in 1777.<br />
Blue sapphires are described .by the English embassy to<br />
Ava, of the weight of nine hundred and fifty-one carats.<br />
Mr. Mawe saw a blue sapphire of three hundred and ten<br />
carats. In the crown-jewels of France, there is one rhom-<br />
boidal crystal of one hundred and sixty-six carats.<br />
A beautiful ruby-asteria, in a breastpin, is worn by Mr.<br />
W. J. Lane, of New York.<br />
COMMON COBUNDUM, DIAMOND SPAE.<br />
This mineral was formerly "brought from China only,<br />
when not so well known as at present, and bore the name<br />
of common corundum, but it is now considered as belong-<br />
ing to the general family of corundum. It occurs in crys-<br />
it has a<br />
tals, which are generally coated with some crust ;<br />
conchoidal fracture, is translucent, and has a lustre between<br />
unctuous and mother of pearl, either gray, red, blue, green,<br />
brown, or whitish in different shadings. It is mostly in-<br />
closed in granite, mica slate, dolomite, or magnetic iron,<br />
and is found in Piedmont, Cananore, Campo Longo, the<br />
East Indies, and Sweden.<br />
All the corundums, possessing fine and pure colors, are<br />
used and cut as jewels, and the impure pieces are pulverized<br />
and used for cutting and polishing harder stones, or<br />
glass .and metals, particularly<br />
so in the East Indies and<br />
China, and it is called, in Madras, the grinding-spar.<br />
It may be remarked that the Chinese corundum, which<br />
is crystallized in prisms of six sides, bears much resem-<br />
blance to the emerald; the hardness and infusibility of<br />
both these minerals, and their geological position in the<br />
middle of old rocks increases their similarity; but the<br />
emerald cleaves in one direction parallel to its base, while
224 A POPULAR TREATISE ON GEMS.<br />
the corundum cleaves in three directions of its f rimitive<br />
angles; the emerald has a less specific gravity, as three to<br />
four ; the phosphate of lime and the tourmaline are also<br />
found in six-sided prisms; but in all these cases are the<br />
cleavage, hardness, and specific gravity the distinguishing<br />
characters. The transparent colorless corundum may be<br />
confounded with the diamond, topaz, aquamarine, white<br />
spinelle, and quartz ; in these cases the specific gravity is<br />
the principal distinguishing character ; the white corundum<br />
weighs 3*970, the diamond 3 '5 20, aquamarine 2*7, spinelle<br />
3'64, the topaz 3'4, and the quartz 2'654.<br />
The emery or granular corundum is of an ash-gray,<br />
bluish-gray, and sometimog brown color ; is massive, and<br />
opaque or slightly translucent on the edges ; -is very hard,<br />
and scratches easily glass and quartz ; is found in a bed of<br />
talc, in mica slate, in rounded masses, in Naxos, Italy, and<br />
Spain, and in great abundance on the summit of Gunnechdagh,<br />
near Gumeschkeny, about twelve miles to the east<br />
of Ephesus, and betwe'en Eskihissar and Males," in Asia<br />
Minor, and in Ochsenkop, near Schwarzenberg, in Saxony.<br />
It has been elaborately described by Professor J. Law-<br />
rence Smith, of Louisville, Ky., as to its power as a polish-<br />
ing material. He Jhas ascertained that they all contain<br />
more or less water, and that their specific gravity as well<br />
as their hardness depends upon the percentage of water<br />
therein contained ; but the specific gravity" of a sapphire,<br />
ruby, or emerald, which contains no water, is.4'06 to4'08,<br />
and thatihey generally contain from 1*60 to 3*90 per ce'nt.<br />
of water. This difference does not result" from a decom-<br />
position of the mineral but from their formation ;<br />
he proves<br />
that the presence of water in these minerals which influ-<br />
ences their hardness or specific gravity, was existing while<br />
they were on the point of crystallization, and his experiments<br />
with the emery from China and Asia Minor, have
.<br />
CHRYSOBERYL. 225<br />
led him to a scale of hardness to be used in the application<br />
of emery in polishing the surfaces of certain substances,<br />
such as a slab of stone, or a plate of 'glass, or any<br />
other material upon which emery is generally applied for<br />
polishing. Professor Smith's process consists in the fol-<br />
lowing method: he reduces the emery to a fine powder<br />
in a steel mortar, similar to the one the diamond-grinders<br />
use ; the powder is sifted very fine through a sieve. One<br />
gramme of this fine powder he employs upon a glass plate<br />
of 0*10 inch diameter, and by means of an agate pestle<br />
he rubs the powder circularly and rapidly, until the pow-<br />
der meets with no resistance and makes no scratching<br />
noise ;<br />
the quantity of glass-powder which is hereby taken<br />
up by the emery gives the index, or the power, of the emery<br />
under trial.<br />
CHRYSOBERYL, CYMOPHAIfE.<br />
The name of this gem is derived from the Greek, and is<br />
expressive of its color ; it is also called cymophane. It<br />
was formerly classed with the beryl family, but was separated<br />
from that by Werner.<br />
It occurs, crystallized, in a prismatic form,<br />
also in boulders and grains ; is transparent<br />
to translucent, and possesses double refrac-<br />
tion in a high degree ; its lustre is between<br />
unctuous and vitreous ; exhibits trichroism ;<br />
fracture conchoidal; its color asparagus<br />
and olive green, with a tinge of brown,<br />
yellow, gray, or white. Some specimens<br />
display, sometimes, a milky or bluish-white<br />
lustre. Chrysoberyl scratches topaz and<br />
rock-crystal very distinctly, but is attacked by sapphire ;<br />
the streak-powder is white, specific gravity, 3*6S 3'75 ;<br />
JO-<br />
Fig. 4.
226 A POPULAR TEEATISE ON GEMS.<br />
hardness, 8*5. It becomes electric by rubbing,<br />
and le-<br />
tains this property for several hours : it is infusible by itself<br />
before the blowpipe, but is slowly fusible into a glass bead<br />
with borax. Its component parts are alumina, silica, and<br />
glucia,<br />
with some oxide of iron and titanium. In com-<br />
merce, chrysoberyl is called Oriental chrysolite,<br />
and that<br />
Mr. Ebel-<br />
displaying lustre is called opalescent chrysolite.<br />
man has produced, artificially, the chrysoberyl from its in-<br />
gredients.<br />
Chrysoberyl is mostly found in loose crystals<br />
or in.<br />
boulders in the sand of rivers associated with other gems,<br />
such as spinelle, sapphire, topaz, beryl, &c. In Brazil,<br />
particularly in the diamond district, and more frequently<br />
in Termo Minas Novas, Pegu, Ceylon, and Siberia: like-<br />
wise in Connecticut (at Haddam),- and in New York (at<br />
Saratoga), imbedded in coarse granular granite, and ac-<br />
companied by garnet and beryl.<br />
The chrysoberyl is cut on a brass wheel with emery, and<br />
polished on a pewter wheel with rotten-stone ; it is very<br />
often cut in cabochon and, if perfectly pure and transpar-<br />
ent, in other respects, is set with gold foil, and used for rings<br />
and pins.<br />
The chrysoberyl is in no great estimation, on account of<br />
its indifferent fire and color, but those specimens that take<br />
a high polish, and occur transparent and pure in color, and<br />
it is particularly worn<br />
of varying lustre, are of some value ;<br />
in Brazil. At Paris a chrysoberyl of fine green color, oval-<br />
cut, seven lines in length, and five and three quarters in<br />
breadth, was sold for six hundred francs ; and a very fine<br />
opalescent chrysoberyl nearly five lines long and four broad,<br />
cost six hundred and three francs.<br />
For chrysoberyl have been substituted apatite, fluor spar,<br />
and pastes.; but it is harder than any of these substances.<br />
Chrysolite bears a great resemblance to chrysoberyl in its
SPIXELLE. 227<br />
external appearance, but is much lighter and softer. A<br />
green chrysoberyl was found in Termo Minas Novas, which<br />
weighed sixteen pounds, the largest known. It is in the<br />
possession of the government at Rio de Janeiro.<br />
SPINELLE.<br />
This gem was called by the ancients, carbuncle. It only<br />
occurs crystallized, and mostly in the form of an octahe-<br />
dron, and its modifications. The crystals are smooth,<br />
solitary, or grown together as hemitropes, loose, o.ften<br />
rounded like grains (figure 5 is<br />
a made form of the spinelle ruby) ;<br />
its fracture is conchoidal ;<br />
it is<br />
transparent and translucent ; it<br />
possesses simple refraction of light ;<br />
is of a highly vitreous lustre ;<br />
and<br />
its color is red, turning into the<br />
greatest variety of shadings of<br />
blue, brown, and yellow. We<br />
find, likewise, blue, black, and<br />
green spinelles, which, however, have no commercial value,<br />
on account of their impure color and want of transpa-<br />
rency.<br />
Spinelle scratches quartz, and is attacked by sapphire ;<br />
becomes electric by rubbing; its specific gravity =3*5 2 3,<br />
hardness= 7*56 ; is infusible before the blowpipe. Accord-<br />
ing to Berzelius, the spinelle of Ceylon when heated, grows<br />
first brown, then black, and then opaque, which, on pooling,<br />
passes into green and limpid, and ultimately into its origi-*<br />
nal red. Acids do not affect it ; its component parts are<br />
magnesia and alumina. The spinelle is classed by jewellers<br />
and lapidaries according to its various colors.<br />
1. Ruby spinelle, or spinelle ruby; of a light<br />
or dark
228 A POPULAR TREATISE ON GEMS.<br />
red, and no milky lustre ; shows, if held near the eye, a<br />
tinge of rose-red color.<br />
2. Ruby balais, or balais ruby; pale-red or rose-red,<br />
sometimes with a tinge of brown or violet.<br />
3. Almandine ruby ; of a cochineal-red color, bordering<br />
on blue, violet-blue, and reddish-brown. It is distinguished<br />
from the garnet, likewise called the almandine, by its lighter<br />
color, stronger lustre, and greater hardness.<br />
5. Goutte de Sang is a fine cochineal or blood-red. spinelle.<br />
Spinelle is found in clay, and in the -sand of rivers, with<br />
sapphire, garnet, tourmaline, and other gems. The red<br />
variety occurs in isolated crystals and grains, in alluvial<br />
soil, and in the sand of rivers Ceylon, Ava, and Mysore<br />
also imbedded in gneiss and granite, in Ceylon ; the blue<br />
varieties occur imbedded in granular limestone at Aker in<br />
Sweden, Rohleta and Lojusoken in Finland, Straskau Mo-<br />
ravia, in the dolomite of Nalande, and Candi in Ceylon ;<br />
the white variety is found at La Ricia, near Rome, with<br />
black garnet and green augite ; the grass-green variety<br />
(chloi'ospinelle) is found in the chlorite slate of Slatoust, in<br />
the Ural. The black and brown varieties have numerous<br />
localities ;<br />
those from Orange county, New York, are very<br />
large and perfect octahedrons : one in my possession was<br />
twelve inches in diameter. Spinelle is cut on an iron or<br />
brass wheel, with emery or pulverized diamond, and is<br />
polished either on the same or on a copper wheel, with oil<br />
of vitriol.<br />
Spinelle is cut in the same form as the diamond, and is<br />
set wit^ a foil of copper or gold. Its color is often .made<br />
%iore intense, and its faults, such as flaws and specks, re-<br />
moved, by calcining it carefully.<br />
Lustre, color, and hardness have made the spinelle a<br />
very favorite gem, which is used in a great variety of<br />
ways, as in rings, pins, necklaces, &c.
TOPAZ. . 229<br />
The price of spinelles it is difficult- to determine with<br />
accuracy, as much depends on their properties ; if perfect<br />
and exceeding four carats, they are usually worth half the<br />
price of diamonds equally large. The spinelle ruby and<br />
balais ruby are the most esteemed spinelles, and if of<br />
twenty-four to thirty carats, are worth from two hundred<br />
to four hundred francs ; and such gems are often sold for<br />
true rubies (sapphire).<br />
Zircon is of greater specific gravity and less hardness<br />
than the spinelle, and shows strong and double refraction<br />
of light. Calcined topaz is distinguished by its electric<br />
Burnt amethysts are lighter, and are scratched<br />
properties.<br />
by spinelle. Pastes are likewise substituted for the spinelle,<br />
such as glass colored with gold-purple but as ; the spinelles<br />
are always harder and heavier, the adulterations may soon<br />
be detected.<br />
According to Mr. Ebelman, the artificial spinelle is obtained<br />
by the following mixture, which is put into a platina<br />
capsule and exposed to the heat of a porcelain furnace :<br />
Alum, - 6<br />
grains.<br />
Magnesia,<br />
Fused boracic acid,<br />
Oxide chrome,<br />
TOPAZ.<br />
3<br />
- 6<br />
"<br />
"<br />
O'lO to 0*15.<br />
It is not determined whether the ancients meant by<br />
topaz the same gem as we describe, since the Greeks understood<br />
the topaz to be of a transparent gold-yellow, and<br />
the Romans, of a transparent green-yellow. The name,<br />
which, according to Pliny, is derived from Topazos, an<br />
island in the Red Sea, has no reference to its color. To-<br />
paz was, in former times, thought to possess great medicinal<br />
virtues; for example, as a remedy for mania, and as a
230 A POPULAR TREATISE ON GEMS.<br />
strengthening medicine. The topaz occurs crystallized in<br />
a rhombic prism, but mostly in very complicated forms,<br />
particularly the Brazilian, Siberian, and<br />
Saxonian : it is often found in boulders.<br />
Its fracture is conchoidal ; it is transparent<br />
and translucent ; possesses some<br />
double refracting powers ; a very vivid<br />
vitreous lustre ; clear, straw, sulphur,<br />
wine, and gold yellow colors, sometimes<br />
with a tinge of violet-blue, greenish, and<br />
white. Topaz scratches quartz distinctly,<br />
but is attacked by sapphire. Its streak-<br />
powder is white ; specific gravity,<br />
3*49 to<br />
3 '5 6 ; it is phosphorescent when heated,<br />
Fig. 6.<br />
with a bluish or yellowish lustre,* in small fragments. It<br />
becomes electric either by rubbing, heating, or by pressure,<br />
and retains the property for more than twenty-four hours.<br />
Before the blowpipe, at a strong heat, it is covered with<br />
many small bubbles, and partly loses its color. It is dis-<br />
acids<br />
solved, fusing slowly with borax, into a white bead ;<br />
have no effect upon it. Its component parts are alumina,<br />
silica, and fluoric acid.<br />
In commerce, topaz is distinguished by the following<br />
names :<br />
1. Water clrops, pebbles (gouttes d'eau), clear, limpid.<br />
2. Siberian topaz, white, with a bluish tinge.<br />
3. Brazilian topaz, gold-yellow, with^a<br />
4. Saxon topaz, pale wine-yellow.<br />
5. Indian topaz, saffron-yellow.<br />
6-. Brazilian ruby, light rose-red.<br />
7. Brazilian sapphire, light-blue.<br />
touch of red.<br />
8. Aquamarine, sea and mountain green.<br />
Topaz belongs to primitive rocks, and is found in chlorite<br />
slate, gneiss on gangues, argillaceous schist,
TOPAZ. 231<br />
zil, it is found in a decomposing chlorite slate (and is there<br />
called malacheta), within brown hematite cavities or quartz<br />
gangues, which are of one inch to one and a half feet thick,<br />
and are overlaid by indurated talc and white and brown<br />
kaolin, and sometimes intermixed with quartz crystals<br />
and* micaceous iron, which are the surest indications of<br />
topaz. Such topaz localities are at Villa Rica, Capao, and<br />
Lana. Little attention is paid during the dry season to<br />
the digging of topaz ; but with the beginning of the rainy<br />
season, the searches for topaz are undertaken, and the<br />
operation for washing and procuring them is performed<br />
like that of the diamond, mentioned under its proper<br />
head.<br />
In places where the topaz is found in company with tin<br />
ore, it is picked out ; but where it forms a part of the rock,<br />
it is wrought by mining operations, as in Saxony.<br />
Topaz is cut on a leaden wheel, either with emery or pulverized<br />
topaz, and is polished on a copper wheel with rottenstone.<br />
Care has to be taken in slitting the foliage. The<br />
forms which it is to receive depend upon its qualities and<br />
purposes. The white topaz is cut in brilliant form, with a<br />
small table ; the bluish topaz, however, is cut with a mixed<br />
form, but it is to be observed that the table side requires<br />
to be higher than usual, the. table smaller, and the collet<br />
side, with its steps, must be attentively wrought in propor-<br />
tional distance. The yellow topaz is mostly cut as brilliant<br />
or table-stone, and in setting, its back is supplied with a<br />
gold foil, and the pale with a red-colored foil. Many spe-<br />
cies of topaz are set d jour. Topaz assumes, by calcining,<br />
a different color, and also by coloring fluids, as stated in a<br />
former chapter. %<br />
The topaz is in general use by jewellers for setting in<br />
lings, pins, ear-rings, seals, or necklaces. Its fragments<br />
are pulverized and used for grinding the softer precious
232 A POPULAR TREATISE ON GEMS.<br />
stones ;<br />
this is effected by calcining them first, then throw-<br />
ing them into water, and afterwards pulverizing them.<br />
By heat the topaz assumes a pink or red hue, so nearly<br />
resembling the balais ruby that it can only be distinguished<br />
by the facility with which it becomes electric by friction.<br />
Topazes from New South Wales, Brazil, and Scotland,<br />
sometimes contain cavities, in which Sir David Brewster<br />
discovered two fluids, one of which has an index of refrac-<br />
tion=l*211, and expands 0*25 of its original vo.lume on<br />
being heated, from 10 to 27.<br />
The topaz is found green, blue, and colorless at Ala-<br />
baschkka Meersinsck, Miask, and Adum Tschelon in Sibe-<br />
ria ; Kamtschatka, Peru, and Rozena in Moravia, with lep-<br />
idolite ; Mucla in Asia Minor, Peneg in Saxony, and at<br />
Schneckenstein, near Auerbach, in Saxony, of a wine-yellow<br />
color; at Villa Rica, in Brazil, of a deep-yellow color;<br />
with tin ore at Geyer, Ehrenfriedersdorf, and Altenberg<br />
in Saxony, Schlackenwald in Bohemia; with tin ore and<br />
apatite in veins of granite at St. Michael's Mount and Huel-<br />
in granite in the Morne<br />
kirid, near St. Agnes in Cornwall ;<br />
mountains in Ireland ; in the United States, at Trumbull<br />
and Middletown, Connecticut.<br />
The less transparent variety (pyrophysalite), with fluor<br />
in granite veins, at Tinbo, near Fahlun, in Sweden ;<br />
in bouX-<br />
ders at Braddbo, in Sweden ; in gneiss at Fossun, in Norway.<br />
Topaz is generally of less value now than formerly, owing<br />
to the yearly supplies obtained from Brazil, which is about<br />
forty pounds. The mine at Capao has yielded about twelve<br />
thousand dollars' worth, and the supply has been accumu-<br />
lating at Rio de Janeiro and Bahia to such a degree, that<br />
it is disposed of at^ less price there than at the mines.<br />
Those most esteemed are the rose-red and the white, or<br />
water drops, pingos cFagoa. A topaz of the size of a bean<br />
is sold at Chapada, in the Termo Minas Novas, at one
TOPAZ. 233<br />
dollar ; one of one carat is disposed of at an average rate,<br />
for eight dollars; a yellow one for three dollars; and a<br />
yellow burnt one for five dollars. In Brazil, very large,<br />
*<br />
fine, and lustrous ones, bring thirty dollars.<br />
The Saxonian topazes are less valued, yet good yellow<br />
or crimson colored ones, nine lines long and seven broad,<br />
bring four hundred and twenty francs.<br />
Aquamarine and chrysolite are sometimes substituted<br />
for topaz; but it may easily be distinguished from them,<br />
not only by its hardness, fracture, and specific gravity, but<br />
more especially by its property of becoming electric by<br />
rubbing. This will prevent, the substitution of either of<br />
the above, or those most resembling them; such as the<br />
yellow quartz, chalcedony, or other yellow-colored stones.<br />
According to the account of Tavernier, the Grand Mogul<br />
possessed an octangular polished topaz of one hundred and<br />
fifty-seven and three quarters carats weight, which has been<br />
purchased for sixty thousand dollars.<br />
M. d'Eshwege notices- a topaz crystal ten inches in length<br />
and four inches in diameter. The United States (Connect-<br />
icut) yield topazes of an opaque color^ pale, dark orange,<br />
and yellow, twelve inches in length. One of the finest<br />
Brazilian topazes I have seen is in the rare collection of<br />
Robert Gilmore, Esq., of three inches length, and perfectly<br />
terminated. The Brazilian topaz on the frontispiece was<br />
exhibited in the London Palace by Mr. Tennant. Some<br />
very splendid cut Oriental topazes I saw at *Mr. Stephen<br />
H. Palmer's; they were of wine-yellow color and good size.<br />
In the French Imperial Bibliotheque there are several<br />
engraved topazes Philip II. and Don Carlos in white<br />
topaz, and engraved by Jacques de Trezzo ; and in a very<br />
large and deq) yellow topaz, an Indian Bacchus, in the<br />
Vatican. The House of Orleans had a Mercury seen in<br />
profile, on ah Oriental topaz, with eight facets.
234 A POPULAR TREATISE ON GEMS.<br />
In Turin, in the Generosio collection, was a topaz in-<br />
taglio, representing Victory in a chariot drawn by two<br />
horses.<br />
Caire possessed an Oriental topaz of twenty-nine carats,<br />
pierced lengthwise, with the following words in Arabic let-<br />
ters : "God only will accomplish." It was an amulet,<br />
known by the Arabs as gri-gri.<br />
The ancient rona&v was found on an island in the Red<br />
Sea, which was often surrounded with fog, and therefore<br />
difficult to find ; it was hence named roTra^a, to seek. This<br />
name, like most of the rnineralogical terms of the ancients,<br />
was applied to seyeral distinct species! Pliny describes a<br />
statue of Arsinoe, the wife of Ptolemy Philadelphus, four<br />
cubits high, which was made of ronafrv, but evidently not<br />
the topaz of the present day, nor chrysolite, which has<br />
been supposed to be the ancient topaz. It has been con-<br />
jectured that it was a jasper or agate ;<br />
it to be a prase or chrysoprase.<br />
. EUCLASE.<br />
others have imagined<br />
Monoclinohedric figures ; cleavage clinodiagonal, highly<br />
perfect, very brittle and fragile ; conchoidal<br />
fracture ; hardness, 7*5 ; spe-<br />
cific gravity, 3* ; transparent ; splendid<br />
vitreous pale mountain-green, passing<br />
into yellow, blue, or white. When<br />
heated befor^ the blowpipe, it intu-<br />
mesces, and melts in thin splinters to a<br />
white enamel; is not acted upon by<br />
acids; is composed of 44'7 silica, 31*8<br />
alumina, and 23'5 glucine, with 1 to<br />
2-2 peroxide of iron, and 0*4 to 0*7<br />
oxide of tin. It is found in chlorite<br />
slate at Boa Vista 'and Capao, near
EMERALD. 235<br />
Villa Rica, in Brazil ; in Peru, and is said to have been<br />
found in Siberia. It is very rare, and for this reason not<br />
much used as 'a gem ; it resembles much the aquamarine<br />
when cut.<br />
EMERALD.<br />
The emerald proper and the beryl belong to this mineral<br />
species, and are distinguished by their color and crystalline<br />
form. The emerald occurs in six-sided prisms with their<br />
modifications; it scratches quartz, and is scratched by<br />
topaz. The streak-powder is white ; its hardness is 7*5 to<br />
8*0 ; specific gravity, 2'73 to 2'76 ; it becomes electric by<br />
rubbing ;<br />
it is rounding before the blowpipe,<br />
and forms an<br />
opaque black, but becomes a green or limpid glass, having<br />
the hardness of borax. Its constituents are glucia, alumina,<br />
and silica.<br />
THE EMERALD PROPER.<br />
The emerald appears to have been known in the most<br />
remote ages, and was the third stone, according to Cal-<br />
met's arrangement, on the high priest's breastplate of judgment,<br />
with the name of Zebulon inscribed on it. In the<br />
time of Pliny, this stone was held in such high estimation<br />
that it was seldom if ever engraved upon. The moderns,<br />
however, did engrave on the same, as we find in the royal<br />
collection at Paris a head of Henry IV., and one of Louis<br />
XIV. It has been excavated from the ruins of Rome, and<br />
from Herculaneum and Pompeii. But the ancients often<br />
included under this name other gems of the same color ;<br />
such as the green fluor, aquamarine, jasper, malachite, &c.<br />
They appear to have' obtained the emerald from Egypt.<br />
Cailloud has in modern times succeeded in finding the old<br />
emerald mines in the Theban deserts,' on the Arabian Gulf<br />
which have been noticed by the ancient authors, and by
236 A POPULAR TREATISE ON GEMS.<br />
the traditions of the Arabs, as coming from the mountains<br />
of the Sahara when sent on an exploring expedition by<br />
the Pasha of Egypt. He mentions having found subterra-<br />
nean mines, capable of allowing four hundred men to work ;<br />
and he likewise found tools, ropes, lamps, and other uten-<br />
sils. He, judged from the ruins of the architecture of the<br />
temples of a city which he discovered, that- they were of<br />
Egyptian or Grecian form, and about one thousand years<br />
old.<br />
Among<br />
the church treasures of the ninth and tenth centu-<br />
ries, we find the emerald, which came into particular notice<br />
after the conquest of Peru, where an emerald the size of<br />
an ostrich egg is said to have been idolatrized by the savage<br />
inhabitants. The' emerald was formerly used as medicine,<br />
and was worn "as a preventive against epilepsy.<br />
The emerald occurs in somewhat depressed<br />
six-sided prisms ; the lateral faces of which are<br />
smooth ; the fracture is conchoidal to uneven ;<br />
it is transparent to translucent ; displays double<br />
refraction in a slight degree ; has a vitreous<br />
lustre; is green and emerald-green<br />
different shades.<br />
with its<br />
According to Mr. Ebelman, the true emerald is prepared<br />
artificially by<br />
Silica - 7* grains.<br />
Alumina - 1*60<br />
Glucia - 1-40<br />
Fused boracic acid - 4*06<br />
Oxide chrome - O'lO<br />
It is scratched by an English file, and scratches strongly<br />
white glass, and slightly quartz. Its specific gravity is 2*73<br />
to 2*77. Its color is owing to the oxide of chrome. An<br />
emerald when calcined, and thrown into water, crumbles<br />
"<br />
"<br />
"<br />
"
EMERALD. 237<br />
into pieces of different colors. The purest emeralds are<br />
called the Peruvian.<br />
The emerald is found in micaceous schist at Salzburg, in<br />
the Sahara mountains, in gangues in Peru, in the argillaceous<br />
and in hornblende slate. Formerly, the finest<br />
emeralds came from Warta, in Peru; but the mine is<br />
either exhausted, or the Indians filled up "the mines before<br />
they left them at the conquest. The best are now found<br />
in the valley of Tunca, in Santa Fe, where they occur in<br />
granite. The emerald has lately been discovered in Siberia,<br />
in the micaceous schist, and is equal to the Peruvian in<br />
every respect.<br />
The emerald is sawed into pieces with emery, cut on the<br />
copper wheel, and polished on a. finer wheel with rotten-<br />
stone, pumice-stone, tin-ashes, ancl water. .The step-cut,<br />
and the mix^d step-cut, or the table-cut, are mostly used,<br />
yet it is sometimes cut as a brilliant or rose-cut. They are<br />
set with a green foil or green satin on their back ; *or some-<br />
times in a back colored with mastic, and very black ; but<br />
if perfectly pure, and of fine color, they are set djour. On<br />
exposure to air, emeralds grow by degrees paler.<br />
The* emerald is, on account of its agreeable green color,<br />
a very favorite ornament, and is . used' for the most expen-<br />
sive kinds of jewelry. Its value' depends altogether ^upon<br />
its pure and fine color, vivid lustre, and the size of the<br />
specimen. The price of emeralds was much higher before<br />
than it has been since the discovery of Mexico ; the prod-<br />
uct of the mines of Pern reduced their price considerably;<br />
now they are getting dearer again, and always command a<br />
good price. A small box of fair 'emeralds from Peru,<br />
which I saw a few. years ago, at the oifice of the American<br />
and Foreign Agency, in this city, which ^weighed from<br />
three to four pounds, was sold afterwards at Paris for nine<br />
thousand francs. A good emerald, of fine color, is worth
238 A POPULAR TEEATISE ON GEMS.<br />
twelve dollars per carat ;<br />
to its intSrior. qualities. Jhe price<br />
and the price increases according<br />
of the best emeralds of<br />
4 grains is 18 dollars.<br />
8<br />
16<br />
24<br />
48<br />
"<br />
30<br />
" ... 200<br />
" ... 300<br />
.<br />
"<br />
'1000<br />
Good emeralds, meaning 'good color and quite free from<br />
flaws, are very rare, and have nearly as much value as the<br />
ruby.<br />
An emerald of twenty-four grains, and good color, was<br />
sold at the auction of the Marquis de .Dree, for two thou-<br />
sand four hundred francs. Emeralds of indifferent pale<br />
color, are sold for two 'dollars per carat. The faults to<br />
which emeralds are subject, are inequality of color and<br />
transparency, dark or white spots, fissur.es, and feathers.<br />
. For emeralds, there are sometimes substituted the green<br />
tourmaline. and apatite; the former is easily detected by<br />
its property of becoming electric by heating ; but in general<br />
all these stones do not 'possess the lustre and hardness<br />
of the emerald. The pastes in imitation of the emerald,<br />
are so well manufactured that it is often difficult to dis-<br />
criminate the genuine from the false. The following yields<br />
the best imitation of the emerald :<br />
1000 parts of discolored strass,<br />
8<br />
"<br />
pure oxide of 02<br />
"<br />
copper,<br />
oxide of chrome.<br />
An emerald is said to have been at the Chapel of our<br />
Lady at Loretto, in Italy, larger than a man's head, and for<br />
which an Englishman offered ninety thousand crowns.<br />
The Sultan of Oude, in the East Indies, is said to have<br />
given to the King of England, among other presents, an<br />
emerald of the size of a hen's egg.<br />
"<br />
"<br />
"<br />
'"
EMERALD. 239<br />
The treasury of Vienna is said to contain an emerald of<br />
two thousand, two- hundred and five carats, valued at three<br />
hundred thousand crowns.<br />
The most magnificent specimen of emerald was presented<br />
to the cathedral of Loretto, by one of the Spanish kings.<br />
It consists of a mass of white quartz, thickly implanted<br />
with emeralds, more than an inch in diameter.<br />
An emerald belonging to the crown of Russia, is noticed<br />
in the Memoires du r&gne de Catherine, Tmperatrice de<br />
Ritssie, as being of the size of a hen's egg. . '<br />
A fine crystal in the matrix, is in the museum at Dres-<br />
den, which I examined in 1827.<br />
Among the large emeralds stands foremost the magnificent<br />
crystal belonging to the Duke of Devonshire, as repre-<br />
sented on the frontispiece of this work; it is a regular<br />
six-sided prism, perfectly well formed ; two of the parallel<br />
faces are more developed tha*h the others, so that the<br />
hexagonal base of the crystal has one side larger than<br />
the rest ; the dimensions of the base are 2*36 inches, by<br />
1'97 in diameter, and it weighs eight ounces and eighteen<br />
pennyweights ; it is of a fine green color and perfectly<br />
clear in the upper part, it was found in a vein of dolomite,<br />
which traverses a hornblende rock at Muso, near Santa Fe<br />
de Bogota, in New Grenada.<br />
A prettier but smaller specimen, weighing but six ounces,<br />
is in the possession of Mr. Hope, of London.<br />
Mount Zalora, hi Upper Egypt, affords a less distinct<br />
variety, and was the only locality which was known to the<br />
ancients.<br />
At the New York Exhibition, in 1853, quite a number<br />
of emeralds were shown from the New Grenada mine.<br />
Dr. J. R. Chilton, of New York, has a very beautiful<br />
crystal of emerald in the matrix in his private cabinet, of<br />
one inch in length.
240 A POPULAR TREATISE ON GEMS.<br />
The largest cut emeralds and in great profusion, set in<br />
bridles, saddles, and in the girdle of an- apron, about the<br />
size of pigeons' eggs, were in the East India Company's<br />
collection. From forty to fifty of that size were set to-<br />
gether, some of them not well cut and polished, but all<br />
transparent and of beautiful tainly very<br />
green color, they were cer-<br />
valuable.<br />
Mr. Herz, of London, has a beautiful polished emerald<br />
of 112 carats.'<br />
Mr. Stephen H. Palmer, jeweller of this city, has some<br />
very fine cut emeralds, one of which weighs four and seven<br />
eighths carats, for which he asks $350.<br />
The prettiest cut emerald is in the imperial cabinet of<br />
St. Petersburg ; it weighs thirty carats ; is of pure color,<br />
and a perfect stone ; it has a round form with too many<br />
facets.<br />
The emerald has been* very successfully imitated, so<br />
much so that the most experienced eye may sometimes be<br />
deceived.<br />
BERYL, AQUAMARINE.<br />
This gem was likewise known to the ancients, who con-<br />
sidered and described it as a sea-green precious stone, and<br />
called the yellow varieties of this mineral the chrysoberyl.<br />
It was used' by the Romans as ornaments for cups, also for<br />
cameos. The crystals of the beryl are six-sided, terminated<br />
by six-sided pyramids, they also taper gradually from one<br />
end to the other ; the lateral faces are striated ; the frac-<br />
ture is conchoidal or uneven ; they are transparent or trans-<br />
lucent at the angles, with indistinct double refraction, and<br />
vitreous lustre : the colors are green, bluish-green, yellow-<br />
ish-green, or greenish-white ; bluish, sky, smalts, or indigo<br />
blue ; straw, wax, or honey yellow ; all pale colors : hard-<br />
ness,?^ ; specific gravity, 2'67 to 2:71. According<br />
to its
BERYL. 241<br />
color and transparency, it is designated the common and<br />
precious beryl :<br />
under the first are generally comprised the<br />
greenish and blue varieties, which are also called the aqua-<br />
'<br />
marine whereas the ;<br />
yellowish varieties are exclusively<br />
called the beryl, and are generally divided thus :<br />
1. Aquamarine, pure pale sky-blue. .<br />
,<br />
2. Siberian aquamarine, pale greenish-yellow, of a vivid<br />
lustre, faigt color.<br />
3. Aquamarine chrysolite, greenish-yellow, and yellowish-<br />
green, vivid lustre.<br />
The beryl belongs to the primitive formation, is found<br />
in quartz veins and granite (graphic granite), and is associ-<br />
ated with garnets, quartz, chrysoberyl, schorl, topaz, &c.<br />
The most magnificent beryls come from Siberia, Rio de<br />
Janeiro in Brazil, Aberdeenshire in Scotland, and Limoges<br />
in France. The common and translucent beryl occurs all<br />
over the globe, and in the United States in great abund-<br />
ance, where it is without mercantile value. The granite<br />
rocks of New Hampshire (at Acworth), have brought<br />
forth gigantic beryls, perfect six-sided crystals, three fee,t<br />
in length and four feet in circumference, and weighing up-<br />
wards of three hundred pounds, and some with a distinct<br />
termination of the crystals. Specimens of this description<br />
may be seen in the collection of the Lyceum of Natural<br />
History, New York, in Mr. Gilmore's collection at Baltimore,<br />
and in the author's collection. Large quantities of<br />
beryl crystals have also been found in Chester county,<br />
Pennsylvania.<br />
The beryl is cut on a leaden plate with emery, and<br />
polished with rotten-stone on a tin plate, and generally of<br />
the brilliant cut, on account of Its not possessing much<br />
lustre in the interior.<br />
The foil that is required in mounting, depends upon the<br />
color of the stone : the greenish variety, for instance, is set<br />
11
'<br />
24:2 A POPULAR TREATISE ON GEMS.<br />
with a greenish-blue foil ; the pale is set in a black ground,<br />
like the diamond, or on a silvery foil.<br />
Beryl is- employed in jewelry for rings, pins, ear-drops,<br />
seals, &c. : but 011 account of its softness it is rendered<br />
less lasting, and as by wearing it loses all its beauty, it<br />
does not command a high price in market, being much<br />
below that of the emerald.<br />
A beryl of a carat, averages about one dollar and fifty<br />
cents, and the price increases in the same ratio with the<br />
number of carats. The beryl is subject to such faults as<br />
spots, feathers, and fissures.<br />
For the beryl, is sometimes substituted chrysolite, which<br />
is softer, however ; it is also imitated by paste, which ia<br />
likewise softer than beryl.<br />
One of the largest transparent beryls, weighing five<br />
hundred and ninety-five carats, was once in the possession<br />
of a mineralogist at Vienna. In 1811, a beryl of fifteen<br />
pounds, pure, was discovered in Brazil. In 1825, a beautiful<br />
rounded Brazilian beryl, of four pounds weight, was<br />
offered for sale for six hundred pounds sterling.<br />
Mawe describes a pure transparent beryl, altogether free<br />
of faults, seven inches long antf three quarters of an inch<br />
thick.<br />
In 1827, a superb aquamarine, weighing thirty-five gram-<br />
mes, was found in the borough of Mowzzinskaia, in Siberia,<br />
which the Russians are said to value at six hundred thousand<br />
francs. A very remarkable aquamarine, of extraordinary<br />
size, ornamented the tiara of Pope Julius I.<br />
There is also a very fine aquamarine in the Imperial<br />
Library of Paris, on which there is a well-executed engraving,<br />
by Erodus, of Julia, daughter of Titus.<br />
There is, according to Caire, another aquamarine in<br />
London-, weighing five hundred and forty carats. In the<br />
Mineralogical Museum, of Paris, there is an aquamarine
BEEYL. 243<br />
weighing one hundred and thirty-three grains; and another<br />
one in a rough state, and extremely beautiful, weighing<br />
over twenty carats, for which 15,000 francs were offered.<br />
There are many of the intaglios of the ancients in the<br />
aquamarine.<br />
Pliny speaks of the finest beryls as those "qui viridatem<br />
piiri maris imitantur," and hence the term aquamarine is<br />
applied to those beryls which have beautiful shades yf skyblue<br />
or mountain-green colors.<br />
The aquamarine was much employed by the ancients for<br />
engraving : there is one by Qnintillius, of Neptune mounted<br />
on marine horses ; another of a drunken Hercules, by Hyllus.<br />
A similar intaglio, with terrestrial instead of s^a horses,'<br />
is the treasure of Odescalchi.<br />
The specimen of beryl on the frontispiece was the prop-<br />
erty of Baron Struve, Russian ambassador at Hamburgh ;<br />
was of grass-green color, fifteen inches long and two inches<br />
in diameter. A similar, but smaller, specimen, and more<br />
yellowish-green in color, was in the case of Mr. J. Tennant,<br />
of London, at the Exhibition of 1851. Both are Siberian<br />
beryls. The most splendid specimen, weighing eighteen<br />
and a half pounds, which formerly belonged to Don Pedro,<br />
in size and form, resembles the head of a calf, and exhibits<br />
a crystalline structure on one side only ; the* rest is water-<br />
worn, perfectly transparent, and without a flaw, and of<br />
a fine gale bottle-green color. Beryls are frequently ob-<br />
tained in Brazil and Siberia of one foot in length, but they<br />
are commonly very deeply striated longitudinally.<br />
Mr. Francis Alger, of Boston, informed the author ot<br />
having obtained a huge beryl crystal nearly perfect, of one<br />
thousand pounds weight, from Acworth, in New Hampshire,<br />
about fifteen miles from Bellows' Falls. Beryls occur there<br />
in extensive veins of granite, traversing the gneiss. The<br />
localities of beryl are very numerous in the United States.<br />
it
244 A POPULAR TREATISE ON GEMS.<br />
In graphic granite, associated with black tourmaline, good<br />
clear crystals are found in Bocodoniham, and Taphain,<br />
Georgetown, Parker's Island, and at the mouth of Kene-<br />
bec river, in the State of Maine ;<br />
at Goshen and Chester-<br />
field, Mass., in irregular crystals of a pale-green color ;<br />
and<br />
transparent, at Monroe, in Conn., in a granite vein ; in<br />
Had dam, Conn., at the chrysoberyl locality, where the<br />
beryls of yellow and yellowish-green colors are imbedded<br />
with crystals of chrysoberyl and colunibite.<br />
'<br />
ZIRCON, HYACINTH, JARGON.<br />
Zircon*and hyacinth were regarded as distinct minerals<br />
until the improvement in chemical analysis proved the same<br />
constituents to exist in both, particularly zirconia, a peculiar<br />
earth: they are now considered. as two varieties of one and<br />
the same mineral. Zircon is also called jargon, and this<br />
name is either of Ceylonese or French origin. The ancients<br />
denominated hyacinth, the gem which is now known<br />
their true hyacinth was a dark<br />
by the name of carbuncle ;<br />
amethyst. The zircon was formerly used as a celebrated<br />
medicine.<br />
Zircon crystallizes in four-sided prisms, terminated by<br />
four-sided pyramids, with various modifications ;* the crys-<br />
tals are smooth, rough, or uneven; it occurs likewise in<br />
rounded pebbles; it is transparent and translucent; pos-<br />
sesses double refraction in a great degree ;<br />
and has a vivid<br />
vitreous lustre, approaching sometimes to adamantine.<br />
Color, from hyacinth-red to yellow and brown ; also, red,<br />
gray, white, brown, and greenish-gray. It slightly scratches<br />
* See in the frontispiece, a beautiful American zircon, from the cabinet<br />
of Dr. J. K. Chilton, of New York. It was found in Buncombe county,<br />
North Carolina.
ZIRCON.<br />
245<br />
quartz, but is attacked by the topaz ; its streak yields a<br />
white powder ; specific gravity is 4'00 to 4'70 ; hardness,<br />
7'5 ;<br />
it becomes electric by friction ;<br />
is infusible before the<br />
blowpipe, but loses its color at a low heat, the yellowish-<br />
brown, however* becomes redder ; acids do not act upon<br />
it. Its chemical constituents are zirconia an
246 A POPULAR TREATISE ON GEMS.<br />
color of hyacinth is preferable to that of zircon ;<br />
a carat of<br />
the former is worth from fifteen to twenty dollars. Zircon<br />
is imitated by pastes, which may easily be detected by their<br />
lustre, hardness, and specific gravity ; burnt topaz may be<br />
substituted for it.<br />
The jargon is a variety of zircon, being composed of the<br />
same constituents, and differing merely in color from the<br />
first. It is mostly of white, grayish-white, and greenish-<br />
white colors, with tinges of green, blue, red, and yellow ;<br />
but generally of a smoky white color. It usually occurs in<br />
worn angular pieces, or in small, detached crystals, of an<br />
octahedral form. The crystals are smooth, and of a bright<br />
adamantine lustre; have a conchoidal fracture, and double<br />
refraction ; seldom quite transparent ; is harder than quartz,<br />
and of a specific gravity of 4*3 ; loses its color when ex-<br />
posed to the blowpipe flame, but is infusible. It occurs<br />
chiefly in the sand of a river in Ceylon, accompanied by<br />
sapphire, spindle, tourmaline, &c.<br />
On account of its peculiar adamantine lustre, it has often<br />
been substituted for the diamond, and a century ago it was<br />
regarded as an inferior variety of the true diamond, and few<br />
of the precious stones were in more request, especially for<br />
mourning ornaments, for which the dark tone of its color,<br />
combined with its lustre, was supposed peculiarly appro-<br />
priate. It has no value, at present, in market, although<br />
it is still seen in the cabinet and in the collections of<br />
jewellers.<br />
Hyacinth differs from jargon and zircon only in color,<br />
being of a red orange color, very bright and transparent ;<br />
it is much more employed for. setting than zircon. It<br />
occurs also in the sand and alluvial deposits of some rivers<br />
in Ceylon ; at Espaillie, near Puy^ in France ; at Ohlapian,<br />
in Transylvania ; occasionally in volcanic tufa, in Auvergne,<br />
and at Vesuvius. Siberia affords crystals as large as -wal-
nuts. Splendid specimens<br />
GAENET. 247<br />
Occur also in Greenland and<br />
Hyacinth is not highly prized by the jeweller. A<br />
large hyacinth of two hundred and fifty carats, in the collection<br />
of Mr. Herz, of London, was offered at a nominal<br />
sum of fifty pounds. Wm. J. Lane, Esq., of New York,<br />
has a beautiful seal-stone of hyacinth, which the author has<br />
much admired. Mr. Herz has also a cut zircon of forty-six<br />
carats, which he values very highly.<br />
It is very doubtful whether the modern hyacinth is one<br />
of the number of stones called hyacinths, vdftivdo^ by the<br />
ancients. It is supposed that the name was applied to the<br />
amethyst pr sapphire.<br />
Garnet was well known to the ancients, who consid-<br />
ered the carbuncle as the same mineral, representing the<br />
whole species. It has been found among the ruins of Rome,<br />
in a variety of cut forms. But the name garnet is of<br />
modern origin, and probably was bestowed on this mineral<br />
from being found mostly in grams.<br />
The garnet crystallizes in dodecahedral forms, with many<br />
modifications; the crystals are sometimes flattened into<br />
and mas-<br />
tables; it -is also found in round angular grains,<br />
sive ; the structure is imperfectly lamellar ; fracture, more<br />
or less conchoidal, sometimes uneven and brittle ; lustre,<br />
shining vitreous; it is transparent and translucent; the<br />
color is blood, cherry, or brownish red, but almost invariably<br />
with a violet or blue tinge ; sometimes, however, we find<br />
garnet of a yellow, green, brown, or black color.<br />
The red garnet scratches quartz faintly, but is attacked<br />
by topaz, and even by the file ;<br />
its powder is reddish-green ;<br />
hardness, 6'5 to 7'5 ; specific gravity if from 3'1C to 4'30 ;
248 A POPULAR TREATISE ON GEMS.<br />
it becomes electric by friction ;<br />
heated by itself, the garnet<br />
grows darker, but resumes its color when cooled ; it fuses<br />
before the blowpipe into a black pebble. Its chemical<br />
constituents are silica, alumina, and the protoxides of iron<br />
and manganese.<br />
Garnet has names according to the different shadings of<br />
color :<br />
1st. Syrian garnet, which is also called the Oriental and<br />
precious garnet, almandine, carbuncle ;<br />
red, dark crimson color.<br />
this is of a blood-<br />
2d. Bohemian, or Ceylonese garnet, called the pyrope ;<br />
wine-red, nearly orange-yellow, deep colored.<br />
3d. Vermeille, or Aplome, having a deep shade of orange-<br />
yellow.<br />
Pliny describes vessels of the capacity of a pint, formed<br />
from carbuncles<br />
" non claros ac plerumque sordidos ac sem-<br />
per fulgoris horridi" devoid of lustre and beauty of color,<br />
which probably were large common garnets. The garnet<br />
is also' supposed to have .been the hyacinth of the ancients.<br />
a dark blood-red<br />
Pyrope is described #s presenting<br />
color by reflected light, but yellow .by transmitted light.<br />
Pyrope was so called from Ttvp, fire, onTopcu, to see, in allusion<br />
to its color.<br />
The almandine, or precious garnet, is transparent and<br />
brownish-red, while pyrope is blood-red. The" red garnet<br />
occurs imbedded in mica slate, granite, and gneiss,<br />
rarely in limestone, chlorite slate, serpentine, and lava, and<br />
is found in the greatest perfection in Ceylon, in the sand ot<br />
and in the alluvial soil of Pegu, Hindostan, Brazil,<br />
rivers ;<br />
and Greenland ; in Bohemia, in alluvium, near Collin ; in<br />
gneiss- at Zbislau; in Tyrol, in the Oetzthal, and on. the<br />
Greiner, in Carinthia, Styria; in Switzerland; at Ariolo,<br />
in Hungary, Sweden, Norway, Scotland,<br />
and in the United States, in North Carolina, Geor-<br />
Canaria, Maggia ;<br />
Spain ;
GAENET. 249<br />
gia, Massachusetts, and New Hampshire. Professor Edward<br />
Hitchcock once exhibited to the author some beautiful<br />
cut precious garnets from Berkshire county, Massachusetts ;<br />
the Hon. Mr. Clingman, U. S. Senator from North Caro-<br />
lina, has some very handsome transparent garnets from his<br />
district in Buncombe county, North Carolina.<br />
The common garnet is met with in dodecahedrons, from<br />
three to four inches in diameter, at Fahlun in Sweden,<br />
Arendal and Kongsberg in Norway, and the Zillerthal in<br />
Tyrol ; in Moravia, Silesia, and Siberia ; in granular limestone<br />
at Haslan, near Eger, hi Bohemia ;<br />
beautiful crystals<br />
of a rich brownish-red color, disseminated in hornblende<br />
gneiss, are found in Hanover, New Hampshire, in the<br />
United States; dark blood-red and splendid dodecahedrons,<br />
with peached and truncated edges, at Franconia, New<br />
Hampshire, in geodes, in massive quartz, calcareous spar,<br />
and magnetic iron ore ; at Carlisle, Massachusetts, beautiful<br />
geodes of crystals of transparent cinnamon color, accompa-<br />
at Monroe and Had-<br />
nying scapolite in white limestone ;<br />
dam, Connecticut, imbedded in mica slate, also associated<br />
with chrysoberyl, beryl, automolite, and columbite ; large<br />
dodecahedral crystals, two inches and more in diameter, of<br />
a dark brownish-red color, at New Fane and Marlborough,<br />
in chlorite slate ; also in mica slate, in Chesterfield, Massa-<br />
chusetts.<br />
Colophonite is a granular brown variety, and is found in<br />
Arendal, Norway, and forms a large vein in gneiss at<br />
Willsborough, New York, on Lake Champlain; a finer<br />
graded variety of yellow and red colors is found on<br />
Rogers' Rock, at Lake George. The colophonite is com-<br />
posed of coarse, roundish particles, oil-green and honeyyellow<br />
colors, and often possesses a fine iridescence.<br />
Alloehroite is similar to colophonite, but the particles<br />
are impalpable and strongly coherent.
250 A POPULAR TREATISE ON GEMS.<br />
Grossular has a pale gooseberry-green color (whence<br />
its name) ;<br />
in Kamtschatka.<br />
in serpentine, with idocrase, in the Wilni river,<br />
Topazolite is a honey-yellow garnet,<br />
in veins in ser-<br />
pentine ; has small yellow crystals ; found on the Mussa<br />
Alp, in Piedmont.<br />
Aplome presents the form of the dodecahedron, but<br />
the facets are striated, parallel to the shorter diagonal;<br />
its color is brown, sometimes greenish; from Sahla, in<br />
Sweden.<br />
Melanite, from peXag, black, occurs in black dodecahedrons,<br />
sometimes modified in volcanic rocks, on Monte<br />
Somma, in matter ejected by Vesuvius ; Frascati, Albano,<br />
near Rome, the Brisgau, in beds on the older rocks at<br />
Arendel, in Norway.<br />
Pyrenaite is found in minute, black, symmetrical dodec-<br />
ahedrons, and was . so called from its locality in the Pyre-<br />
nees, and at the Pic Eves Lids, near Bareges.<br />
Ouwarowite bears a close resemblance to the green<br />
garnet. It occurs in transparent emerald-green dodecahe-<br />
drons, with a hardness of V'05 harder than the garnet. It<br />
occurs at Bissersk, in Russia.<br />
The several varieties of garnet are quite different in their<br />
composition ; they all contain silicate of alumina, and va-<br />
riable proportions of the silicates of lime, iron, and manganese,<br />
which substances have the property of replacing one<br />
another without causing a change of crystalline form. The<br />
f varieties of garnet are often classed as distinct species, such<br />
as almandine, pyrope, dodecahedral garnet, melanite, grossular^<br />
topazolite, aplome, essonite, cinnamon-stone, Green-<br />
Jandite, pyrenaite, colophonite, allochroite, Romanzovite,<br />
carbuncle, and ouwarowite. It is proper that garnet be<br />
divided into precious and common; the first being the<br />
transparent, and the latter the opaque variety. The pre-
GARNET. 251<br />
cious garnet, is again divided, according to its transparency,<br />
into almandine and pyrope. As already stated, the dif-<br />
ferent varieties differ very little, and as the only important<br />
species, possessing characters more distinctive than<br />
others from the garnet, is the cinnamon-stone, or essonite,<br />
the author has seen fit to separate it from the garnet, and<br />
to describe it under its proper head ; moreover, essonite<br />
is more used by jewellers, when cut, than any of the other<br />
species of garnet,<br />
and as it has of late become fashion-<br />
able, it may be well to give a fuller description<br />
same.<br />
of the<br />
Garnet was the carbunculus of the ancients. This term<br />
was probably applied also to the spinelle and Oriental ruby.<br />
The alabandic carbuncles of Pliny were so called, because<br />
hence the name<br />
they were cut and polished at Alabanda ;<br />
almandine, now in use.<br />
In Bohemia, where there is a considerable trade in gar-<br />
nets, they are separated from the earth by levigation,<br />
then assorted into different sizes, afterwards washed again,<br />
and assorted as to color and quality, and according to the<br />
quantity required for balancing a certain weight, as half<br />
an ounce, they are called 32, 40, 76, 100; very seldom<br />
do they find them 16 to 20, weighing together half an<br />
ounce.<br />
The larger garnets are cut on the leaden wheel with em-<br />
ery, or their own powder, and polished with rotten-stone<br />
or oil of vitriol, on a tin plate, in the form of brilliants,<br />
roses, table-stones, or in cabochon, or with two rows of<br />
facets at the girdle; and very often garnets are brighter<br />
and more agreeable by excavating them circularly on the<br />
bottom ; they are then called garnet-cups. I have in my<br />
possession several large excavated garnets, and I saw at<br />
Berlin, in 1828, such garnets of two and three inches size.<br />
Fine garnets are set d jour others are set with a gold
252 A POPULAR TREATISE ON GEMS.<br />
or violet foil at the base. Smaller garnets are wrought on<br />
a large scale in manufactories for that purpose. They are<br />
perforated with the diamond, first, by<br />
point, then of a larger, and at last a finer point ;<br />
means of a small<br />
one hun-<br />
dred and fifty garnets may be perforated daily.<br />
The best garnets are cut in brilliant iorm, and with regular<br />
facets, on a plate of fine sandstone, with sweet oil and<br />
emery. One man can finish thirty such garnets. in one day.<br />
The polishing on wooden or leaden plates, with rotten-stone<br />
or oil of vitriol, is performed by women and children.<br />
More than twenty thousand garnets are yearly carried to<br />
market from a single manufactory.<br />
Garnets are much worn in jewelry, *as -rings, breastpins,<br />
ear-rings, and necklaces; and sometimes snuff-boxes are<br />
cut out of the larger ones from Greenland, Syria, or Tyrol;<br />
the inferior pieces, unfit for cutting, are calcined and re-<br />
duced to powder, and employed as material for polishing<br />
other gems.<br />
The value of garnets is determined by their degree of<br />
perfection, as well as color, purity, and size. On account<br />
of their peculiarly deep color they must be cut very thin ;<br />
and all such garnets as retain their fine color, without being<br />
cut too thin, are held in high estimation, and stand in value<br />
near the sapphire. A Syrian garnet eight and a half lines<br />
long, and six and a half lines broad, and cut octangular,<br />
was sold at the auction of tne Marquis de Dree for three<br />
thousand five hundred 'and fifty francs. A fire-red oval<br />
Ceylon ese garnet, eleven lines long and seven broad, was<br />
sold for one thousand and three francs. They are generally<br />
sold by the pound, containing from sixty to four hundred,<br />
valued at about eight to ten dollars per pound ; but a set<br />
of one thousand of the best selected garnets, well cut, is<br />
sold at about sixty dollars. Garnet is harder than idocrase<br />
or oxide of tin, but the latter is heavier.
V<br />
253<br />
In the Mineralogical Museum of the Jardin des Plantes,<br />
in Paris, are some very fine garnets with engravings ; one<br />
^s a mask of Silene, crowned with vine leaves; another is<br />
also the bust<br />
Calphurnia's restlessness on the fate of Caesar ;<br />
of Adrian, from the cabinet of Odescalchi the ; dog Syrius ;<br />
a head of Augustus, belonging to the Prince of Orange.<br />
Garnet is very well imitated by pastes, which are,<br />
however, softer and lighter, and differ in many other<br />
respects.<br />
The following composition yields a superior imitation of<br />
the Syrian garnet :<br />
To 1000 parts strass, add<br />
500<br />
"<br />
glass of 4<br />
4<br />
"<br />
"<br />
antimony,<br />
cassius purple,<br />
oxide of manganese.<br />
ESSOXTTE, CIXXAMOX-STOXE.<br />
This gem was formerly considered identical with hyacinth,<br />
under which name it yet passes in commerce and<br />
among manufacturing jewellers, and in France it is called<br />
hyacinth de Ceylon; it is also called, in mineralogical<br />
works, cannel or cinnamon stone, which name it received<br />
from the Dutch gem-dealers, on account of its resemblance<br />
to the oil of cinnamon. Werner was the first who gave<br />
this stone the above name.<br />
*Essonite occurs in crystals and grains; its fracture is<br />
conchoidal and uneven ; it is transparent and translucent ;<br />
has simple refraction of light ;<br />
the lustre is between vitreous<br />
and resinous; its color is deep-red, hyacinth-red, or or-<br />
ange-yellow ; it scratches glass and quartz indifferently,<br />
but is attacked by topaz; its powder is white; specific<br />
gravity is 3'5 to 3*6 ; it becomes electric by rubbing ; acts<br />
sometimes on the magnetic needle ; fuses easily before the
254 A POPULAR ^REATTSE ON GEMS.<br />
blowpipe into a clear not affect it.<br />
greenish glass ;<br />
borax and acids do<br />
Essonite is found in the sand of rivers, and in the primi- t<br />
tive rocks of Ceylon, in considerable masses ; also in Scot-<br />
land.<br />
It is treated like garnet, by being cut on a copper<br />
plate with emery, and polished on a tin wheel with rottenstone.<br />
It also receives the form of other gems, and when<br />
set, it is mounted with a foil answering to its color.<br />
It is used for rings and breastpins. Essonite* is distin-<br />
guished from zircon by inferior hardness, smaller specific<br />
gravity, diminished lustre, and simple refraction of light.<br />
Garnet is heavier, and idocrase is lighter than essonite.<br />
TOURMALINE, RUBELLITE, SIBERITE.<br />
This mineral is as yet very little known among jewellers<br />
and the trade in general, although it has been in commerce<br />
for a number of years past, but under other names, such as<br />
red tourmaline, or siberite, brought from Siberia, and sold<br />
in the trade as Oriental ruby.<br />
Tourmaline was first introduced as a gem by the Dutch,<br />
who imported it from Ceylon. Tourmaline occurs in<br />
crystals and crystalline masses, and<br />
its forms are six, nine, and twelve<br />
sided prisms, with various trunca-<br />
tions and terminations, which com-<br />
monly differ in the number and size<br />
of the faces at the two ends. The<br />
crystals are long, striated, and com-<br />
plete, or aggregated into irregu-<br />
lar masses; the fracture is conchoidal and uneven, semi-<br />
transparent to opaque. It has double refraction of light,<br />
it has a<br />
which, however, is only visible in small pieces ;
TOTTRITALINE. 25 C<br />
vitreous lustre ; the colors are blue, red, green, and brown,<br />
of different shades. Several colors may often be observed<br />
in one and the same crystal, as, for instance, in the rubellite<br />
from Paris, in Maine, and Chesterfield, Massachusetts, in-<br />
closed by the green tourmaline ;<br />
and the color often varies<br />
in its different layers.<br />
Tourmaline scratches glass slightly, but is scratched by<br />
topaz ; its powder is white ; its specific gravity is 3*0 to 3'3 ;<br />
it becomes electric by rubbing, that end having the great-<br />
est number of faces being positive, the other negative.<br />
When tourmaline is heated it exhibits polarity, the iUbst<br />
modified extremity becoming positive and the other nega-<br />
tive. In this particular it resembles other hemihedrically<br />
modified crystals. At a certain temperature it loses its<br />
polarity, but exhibits it again on cooling ; its polarity continues<br />
with the decrease of temperature until it reaches 32<br />
Fahr. ; a continued increase of cold re-excites the electric<br />
polarity, though with reversed poles ;<br />
if the excited crystal<br />
be broken, ach part thus produced will equally possess<br />
polarity, and even in the powdered state it retains its pyroelectricity.<br />
Before the blowpipe it intumesces more or<br />
less, does not fuse, but vitrifies on the edges ; turns green,<br />
then yellow, then red, then milk-white, .then blue, and<br />
then black. Borax dissolves it pretty easily into a clear<br />
bead.<br />
The chemical composition of tourmalines varies greatly :<br />
they are composed of alumine, silica, oxide of iron, oxide<br />
of manganese, and boracic acid ; those from different localities<br />
contain either potash, soda, lithia, or calcia. The<br />
following are the different varieties, not -including, how-<br />
ever, the white, yellow, and black tourmaline, or schorl, they<br />
not being used as gems :<br />
1. Siberian tourmaline (siberite, rubellite, apyrite), which<br />
is of a carmine or hyacinth red, purple or rose red, passing
256 A POPULAR TREATISE ON GEMS.<br />
into violet ; sometimes, by looking through in one direc-<br />
tion, the red color changes into a blue color.<br />
2. Indicolite (Brazilian sapphire), of an indigo, lazulite,<br />
or Prussian blue color.<br />
3. Brazilian tourmaline (Brazilian emerald), of a grass-<br />
green or olive-green color.<br />
4. Ceylonian tourmaline (Ceylon chrysolite), of a green-<br />
ish-yellow color.<br />
5. Electric schorl, of a yellowish, reddish, liver, or black-<br />
ish brown color.<br />
^mrmaline occurs in rocks, such as granite in layers<br />
and gahgues, and in boulders ; it also occurs in the beds<br />
of rivers, and the localities are Siberia, St. Gothard, Ceylon,<br />
Brazil, Sweden, Saxony,<br />
and Moravia. In the United<br />
States, tourmalines are abundant, but there are very few<br />
localities of the betfer varieties, as those at Paris in Maine,<br />
and Chesterfield and Goshen in Massachusetts.<br />
The specimen of a crystal of rubellite, from Paris, Me.,<br />
on the frontispiece, is a perfect prism, is dark^ red on the<br />
inside and dark green on the outside, and belongs to Prof.<br />
Charles U. Shepard, of. New Haven, who exhibited it in<br />
thje New York Exhibition in 1853. There are several<br />
beautiful green and red transparent tourmaline crystals,<br />
from the same locality, in the mineralogical museum of<br />
Yale College, from the collection of the late Baron Lederer,<br />
Austrian consul in this city.<br />
The yellow tourmaline, from Ceylon, is but little inferior<br />
to the real topaz, and is often sold for that gem. The green<br />
tourmaline, when transparent, is often highly prized.<br />
The Siberian red tourmaline, called .siberite, is cut in<br />
cabochon, and exhibits then a milk-white chatoyant lustre.<br />
The black tourmaline is called schorl. The localities of<br />
tourmaline are quite numerous : large size black tour-<br />
malines are found in Greenland at Hovelberg, in Bavaria<br />
'
TOURMALINE. 257<br />
near Bodenmays, at Karinbrida in Sweden, and near Bo-<br />
vey in Devonshire. Small brilliant crystals are met with,<br />
imbedded in decomposed felspar, at Andreasberg, in the<br />
Hartz mountains, forming the variety called aphrigite. Ru-<br />
bellite occurs in a species of lithomarge, near Ekaterinen-<br />
burg in Siberia ; pale yellowish-brown crystals<br />
are found in<br />
talc at Windiscji Kappell, in Carinthia ; white and varie-<br />
gated colored specimens come from St. Gothard and Sibe-<br />
ria, the first imbedded in dolomite.<br />
In the United States, some magnificent specimens of red<br />
and green tourmalines were found in 1829 at Paris, State<br />
of Maine ;<br />
some transparent crystals from that locality ex-<br />
ceed two inches in diameter, and very frequently one inch,<br />
and present a clear red color internally, surrounded by<br />
green, or are red at one extremity and green at the other.<br />
Blue and pink varieties, most commonly imbedded in lep-<br />
idolite, are yet occasionally found in this locality.<br />
Red and green tourmalines occur also at Chesterfield,<br />
Mass., in a narrow vein of granite traversing gneiss ; the<br />
crystals are commonly small and curved, nearly opaque,<br />
and exceedingly frangible. Green crystals often contain<br />
distinct prisms of a. red color, especially when they occur in<br />
smoky quartz ;<br />
blue tourmalines also occur at this locality,<br />
and are accompanied by albite.<br />
The Russian Mineralogical Museum was supplied, in<br />
1832, by its minister, Baron Crudner, with specimens of<br />
fifty pounds weight, containing the rock of green<br />
and red<br />
tourmalines, from the Chesterfield locality.<br />
At Goshen, Mass., similar varieties occur, and the blue<br />
tourmaline is met with in greater perfection ; very perfect<br />
crystals, of a dark-brown color, occur imbedded in mica<br />
slate, at Monroe, Conn. ; the crystals are commonly from<br />
one to two inches long, and nearly as broad, and uniformly<br />
they are perfectly terminated at the two extremities.
258 A POPULAR TREATISE ON GEMS.<br />
Haddam, Conn., also affords fine black crystals, and some<br />
of large size ; they are profusely mingled in a mica slate,<br />
and associated with anthophylite and hornblende. A cinnamon-brown<br />
variety is met with at Gouverneur, N". Y.,<br />
imbedded with quartz, and also associated with scapolite,<br />
apatite, and sphene, in granular limestone. These crystals<br />
are very often highly modified, and occasionally exhibit the<br />
faces of a scalene dodecahedron in addition to the terminal<br />
planes. Similar specimens occur at Grenville, Lower Can-<br />
ada, and Newton, N". J., associated with corundum, spinelle,<br />
and rutil ; and at Kingsbridge, N". Y., and Carlisle, Mass.,<br />
with garnet.<br />
The red tourmaline, when transparent and free from<br />
cracks and fissures, admits of a high polish, and forms a<br />
most beautiful and costly gem.<br />
It has been supposed that tourmaline was known to the<br />
ancients under the name of lyncurium (Aw/covptov), which<br />
is described as having electrical properties; this name,<br />
however, was more probably applied to some variety of<br />
amber, which was so called from its supposed origin from<br />
the urine of the lynx. The identity of the red tourmaline<br />
with the hyacinth of the Greeks is more probable ; the<br />
other varieties were either unknown, or possibly connected<br />
under a common name with other species of the same color.<br />
Tourmaline received no attention from the moderns till<br />
Lemery, in 1717, published his discoveries. The word<br />
tourmaline is a corruption of the name for this mineral at<br />
Ceylon, whence it was first brought into Europe.<br />
The name schorl, which has been applied to the black<br />
tourmaline and some other mineral species, is reported to<br />
have been derived from Schorland, the name of a village in<br />
Saxony, which afforded specimens of this variety.<br />
Tourmaline is cut on a brass or leaden wheel with<br />
emery, and polished with rotten-stone on a tin plate ; it re-
QUABTZ.<br />
259<br />
ceivcs varfctis forms, such as the step and table cut. If of<br />
a pure color, it is set d jour, otherwise with a foil corre-<br />
sponding to its color ;<br />
but the electric schorl is sometimes<br />
set so that it can be removed from its mounting to be used<br />
in performing experiments. The value of tourmaline de-<br />
pends upon its color, purity, and size. The siberite and .<br />
rubellite stand highest in estimation. A siberite, as large<br />
as* five lines, is worth about one hundred and fifty dollars;<br />
and one of four to twelve lines, good color and pure, is<br />
worth about fifteefl hundred dollars. The rubellite from<br />
Paris, Maine, has become very rare, and it is muqh to be<br />
regretted that no more attention is paid to obtaining a<br />
freh supply, as the crystals are of an exceedingly fine<br />
purple color, and perfectly transparent. I have a few polished<br />
rubellites and green tourmalines in my cabinet, which<br />
I value equally as high as any gems.<br />
The dark-green tourmalines, six. lines long and four<br />
broad, are sold in Paris for eighty francs, and the light-<br />
green, of the same size, for forty francs. The most splendid<br />
siberite is at the British Museum, having been pre-<br />
it is valued<br />
sented by the King of Ava to Colonel Symes ;<br />
at one thousand pounds sterling.<br />
Tourmalines may be readily distinguished<br />
from other<br />
gems or pastes, which are sometimes substituted for them,<br />
by their property of assuming polaric electricity after being<br />
heated. . .<br />
QUAKTZ,<br />
This mineral is diffused all over the globe. Its varieties<br />
are very numerous, and many of them are employed in<br />
jewelry and for divers ornamental purposes. It occurs<br />
massive, in concretions, in confused crystalline masses, and<br />
in crystals, of which the form is the six-sided prism, termi-<br />
nated by six-sided pyramids; also the dodecahedron, or
260 A POPULAR TREATISE ON GEMS.<br />
double six-sided pyramid. Quartz scratches^rlass and<br />
felspar, but is attacked by topaz. Its hardness is 7*0.<br />
and its specific gravity, 2*5 to 2*7 ; it is transparent, and<br />
possesses a vitreous lustre ; becomes electric by rubbing ;<br />
is infusible before the blowpipe. Acids, except the- fluoric<br />
acid, do not act upon it. Silica is the only essential com-<br />
ponent part of quartz, but some varieties contain iron, alumine,<br />
or lime.<br />
ROCK CRYSTAL.<br />
This mineral was know r n in early ages. It was highly<br />
esteemed by the Greeks on account of its purity and very<br />
regular formation. Theophrastes<br />
states that it was "cut<br />
principally as seals, and the ancients made great use of it<br />
for ornaments, particularly before the art of making glass<br />
had reached much perfection. Among the many vessels<br />
which were cut in the form of cups, vases, &c., were two<br />
fine bowls and chalices in the possession of the tyrant ]&"ero,<br />
who purchased them at a large sum. Rock crystal was also<br />
used as a medicine.<br />
It is found crystallized, in the primitive form, which is<br />
the rhomboid, extended to a six-sided pi-ism ; and in a great<br />
variety of forms and modifications, such as with a truncation<br />
or replacement of the edges, or solid angles, &c. It<br />
is frequently found in groups, also in the cavities of other<br />
minerals, or in incrustations, as small, but very perfect<br />
crystals, the pyramidal terminations of which have a high<br />
polish, and the specimen* appearing as if it were studded<br />
with gems. Many specimens of this description were<br />
brought from Vermont a few year's ago, and were eagerly<br />
purchased by the jewellers of this city for rings, earrings,<br />
and breastpins. Rock crystal has a conchoidal frac-<br />
ture ; is translucent and transparent ; possesses a double<br />
refraction of light; a perfect vitreous lustre; is limpid,
ROCK CRYSTAL. 261<br />
white, brown, bla*ck, or yellow; scratches glass; specific<br />
gravity, 2'65. The electricity acquired by rubbing lasts<br />
for thirty minutes. Before the blowpipe, when colored, it<br />
becomes limpid. The following varieties of it are made<br />
known by their names and characters :<br />
1. The pseudo diamond (Bohemian or occidental dia-<br />
mond), which is the limpid, colorless rock crystal, cut and<br />
polished.<br />
2. The iridescent quartz is that variety of rock crystal,<br />
the 'interior of which is replete with fissures and cracks, so<br />
that the refraction of the rays of light produce the rainbow<br />
colors.<br />
3. Citron (Bohemian topaz, occidental topaz, yellow<br />
quartz, Scotch pebble), which is of a pale, ochry, gold,<br />
whitish, lemon, or brownish yellow color. The false cairn-<br />
gouram of Brazil is a beautiful variety of yellSw quartz.<br />
4. Smoky topaz (cairngouram or true Scotch pebble,<br />
brown quartz, smoky quartz) is of a smoky or brown<br />
color.<br />
5. Morion is of a charcoal-black or brownish-black color.<br />
6. Hair or needle stone, or such rock crystal as has, in its<br />
interior, foreign substances, as rutil (red oxide of titanium),<br />
manganese, iron, chlorite, amianthus, or asbestos. When<br />
the stone is so cut as to represent the hair or needles in an<br />
upright position, they are called either Venus' hair (cheveux<br />
de Venus) , or Love's arrows (flbches cf amour).<br />
Rock crystal occurs in gangues, or rock cavities, in the<br />
oldest geological formations ; it is also occasionally found<br />
in some modern rocks.<br />
The mountain of Cairngouram, in Aberdeenshire, Scot-<br />
land, has furnished, and still continues to afford, many fine<br />
specimens of smoky quartz. The lapidaries of Edinburgh<br />
always meet with a ready sale of this far-famed stone<br />
among the* Scottish gentlemen, as the native produce of
262 A POPULAR TEEATISE ON GEMS.<br />
their country. Many very beautiful sets of the Cairjigouram<br />
were exhibited in the London Exhibition.<br />
A group of rock crystal, in the museum of the univer-<br />
sity of Naples, weighs nearly half a ton.<br />
The black limestone of Quebec affords fine crystals of<br />
quartz. In the State of New York, quartz crystals, remarkably<br />
clear and perfect', from the size of a pin's head to four<br />
inches, are found in many localities. Diamond Island, in<br />
La*ke George, is a lamed spot ; Gouverneur, N. Y., affords<br />
splendid dodecahedral crystals, associated with an iridescent<br />
crystallized specular iron. At the Notch of the White<br />
Mountains, N. H., and at the locality of tourmaline at Paris,<br />
Maine, handsome crystals of brown and smoky quartz have<br />
been obtained.<br />
At Trentop Falls, in the State of New York, very perfect<br />
and completely terminated transparent crystals are<br />
found, with their endless modifications, some of them five<br />
inches long, and some containing drops of water. It is<br />
also found at Windham, Vermont, where the drusy variety<br />
occurs, which is extremely beautiful, and of variegated<br />
colors. About twenty years ago it had a great many ad-<br />
mirers, and was generally worn in brooches, rings, &c.<br />
It is also found in Maryland, Massachusetts, and on the<br />
Catskill mountains.<br />
V<br />
Rock crystal is obtained in Switzerland, and some other<br />
countries, by mining; those cavities geologically<br />
or me-<br />
chanically traced from the quartz veins, are sounded by<br />
miners in granite veins or other rocks, by means of in-<br />
struments, and when hollow, extensive preparations are<br />
made for procuring the whole produce of the cavities,<br />
which sometimes amounts to several tons. It is likewise<br />
procured from the sand of rivers, and it passes then under<br />
the name of flints ; also, from gangues or veins of. other min-<br />
erals. The smaller and clearer transparent ones are gener-
BOCK CRYSTAL. 263<br />
ally employed in jewelry and for ornaments ; but the larger<br />
specimens are first assorted and then split or cleaved, and<br />
the smaller pieces are sawed through with a copper wire,<br />
emery, and oil, into the desired sizes, when they are ready<br />
for being cut on copper or leaden discs, with emery and<br />
water, and polished on tin plates with rotten-stone, putty,<br />
bole, or other fine powder; or they may be polished on<br />
wooden wheels, lined with fur or leather. The forms which<br />
they generally receive from the lapidary, are the brilliant,<br />
rose, or table. The iridescent quartz, and the hair or<br />
needle stones, are only cut concave. Those specimens that<br />
"have a full pure wine-yellow color, are best cut in steps.<br />
When mounted, they are either d jour\ or with a black<br />
foil. Those which are spotted, or of an, irregularcolor,<br />
may be discolored by careful calcinati
264 A POPULAR TREATISE ON GEMS.<br />
country as white topaz, and command a fair price. Wellcut<br />
seal-stones are sold at from five to twenty dollars.<br />
Those of the brilliant-cut are sold at from fifty cents to a<br />
dollar a piece.<br />
The largest rock crystal is said to be in the<br />
collection of M. Rafaelli, artist, at Rome, and a large can-<br />
delabra of. iridescent quartz, is in the Vatican. The proprietors<br />
of the American Museum of this city, can boast of<br />
having one of the largest specimens of rock crystal from<br />
Brazil. It weighs two hundred and twelve pounds, is two<br />
feet and a half high, and one foot in diameter, and is a<br />
perfect six-sided prism.<br />
Two large crystals of quartz, attached by one of the-<br />
vertical faces, the crystals being each two and a half feet<br />
high by eight inches in diameter, w r ere exhibited by the<br />
Duke of Devonshine, at the London Exhibition, in 1851.<br />
The pyramidal summits of these crystals, which rise nearly<br />
a foot above the prism, are completely transparent, but the<br />
prisms are cloudy. These magnificent crystals were obtained<br />
from the Alps, having been discovered during the<br />
formation of the road over the Simplon, in a cutting made<br />
through the old rocks. I saw a most magnificent chandelier<br />
of rock crystal in the Tuileries, which is said to have cost one<br />
hundred thousand francs. The clearest rock crystal comes<br />
from the island of Madagascar, in blocks weighing from<br />
fifty to one hundred pounds. In Switzerland, and the province<br />
of Auvergne, in France, very fine specimens may be<br />
had. The Bristol, Buxton, Cornish, and Irish diamonds,<br />
which are all pyramidal crystals -of quartz, are known all<br />
over the world.<br />
A specimen of rock crystal in the Museum of Natural<br />
History, at Paris, measures three feet in diameter, weighs<br />
nearly eight hundred pounds, and was found at Fischbach,<br />
in France. 9<br />
Rock crystal may be easily distinguished from white
BOCK CRYSTAL. 265<br />
paste, called strass, as the latter is heavier, on account of<br />
.the metallic oxides contained in the composition.<br />
A very remarkable phenomenon in quartz is exhibited<br />
by the fluid drops -which are contained in many specimens.<br />
They occupy small cavities, and evince their presence,<br />
on turning the specimens, by the motion of the accom-<br />
panying air-bubble, like the bubble in a spirit-level. These<br />
cavities are sometimes of considerable size. Jacobson, of<br />
Copenhagen, possesses a geode of [quartz an inch and a<br />
quarter long, which contains at least half a cubic inch of<br />
fluid. Mr. Allen also describes a crystal of amethyst in his<br />
collection, which contains four cavities partially filled with<br />
this peculiar fluid. At a temperature of eighty-three de-<br />
grees the fluid dilates and entirely fills all the cavities, and<br />
as it re-appears on cooling, an ebullition is apparent. Sir<br />
David Brewster has ascertained that the. fluid is not, as<br />
was supposed, water, but of an oleaginous nature, from<br />
twenty to twenty-five times thinner than water. A considerable<br />
number of specimens containing the fluid were<br />
carefully examined, and he found that one part of the fluid<br />
is volatile at twenty-seven degrees, and the other was a<br />
fixed oil. Prof. Dana has lately named the "former, cryptoline,<br />
and the latter, brewsterline. There is a great difference<br />
in the specific gravity of both liquids. The more dense<br />
yields a transparent yellow resinous globule, which absorbs<br />
the<br />
humidity of the atmosphere, is insoluble in water and<br />
alcohol, but dissolves in hydrochloric, and nitric acids.<br />
Occasionally a bituminous fluid, resembling napththa, is<br />
contained in the cavities of quartz.<br />
A very peculiar gelatinous substance, appearing to be<br />
silica in solution, has been observed on breaking open<br />
geodes, and the production of a species of chalcedony from<br />
the subsequent evaporation, has also been observed. But<br />
the nature of the solvent of silica is not yet fully ascer-<br />
'<br />
12
266 A POPULAR TREATISE ON GEMS.<br />
tained. It is, however, held in solution in the hot waters<br />
of the Geysers of Iceland, whose solvent power is supposed -<br />
to be due to the presence of a small quantity of alkali<br />
and their high temperature. The Geysers have covered<br />
the part of Iceland in their vicinity with a silicious sinter 1<br />
.<br />
The pseudomorphous quartz, from North Carolina, con-<br />
tains fluids in large quantities in its cavities.<br />
Two pieces of quartz rubbed together in the dark, emit a<br />
phosphorescent light and a faint empyreumatic odor.<br />
AMETHYST.<br />
This gem has been known sinc$ the earliest ages of<br />
Greece and Rome ; the name is of Greek origin. The<br />
ancients believed that wine drank from tm amethyst cup<br />
of that<br />
would not intoxicate ; hence its name, expressive<br />
belief a/K0wn>s-, from a, not ; pcd,<br />
to intoxicate. As re-<br />
gards the color, Pliny says : "ad riciniam crystalli descendet<br />
albicante purpurae defectu," purple gradually fading into<br />
white. This is not, however, the only amethyst of the<br />
ancients ; the violet-colored sapphire, the violet fluor spar,<br />
(" sculptaris faciles," easily graven Pliny,) and some other<br />
purple' species were designated by the same name. It has<br />
also been supposed that 'garnet came under the same de-<br />
nomination. This name occurs in Scripture, being that of<br />
the ninth stone in order on the high priest's breast plate of<br />
judgment, with the name Issachar engraved thereon.<br />
Amethysts were always used for engraving. The bust of<br />
Trajan, in the Royal Library, at Paris, and the Apollo<br />
Belvidere, the Farnese Hercules, and the group of the Lao-<br />
coon, are splendid specimens of it. It occurs massive in<br />
boulders, or in hexahedral prismatic crystals, terminated<br />
by hexahedral pyramids. Its crystals are rarely as distinct<br />
as those of quartz, being, for the most part, latterly aggre-
AMETHYST. 267<br />
gated by the whole prism, the terminal pyramids alone<br />
its fracture is from con-<br />
being separated from each other ;<br />
choidal to splintry ;<br />
it is transparent to translucent; of a<br />
vitreous lustre ; color of a high and dark violet blue, and<br />
from its richest tinge to almost colorless, in one and the<br />
same specimen. It scratches white glass, gives fire with<br />
steel, but yields to the file. Its specific gravity, 2-75 ; becomes<br />
electric by rubbing, which lasts, however, but half<br />
an hour. Before the blowpipe it loses its color. Its com-<br />
ponent parts are pure quartz, colored by manganese and<br />
iron. It occurs in veins of the older formations, studding<br />
the interior of agate balls or geodes in tho amygdaloid and<br />
trap rocks of Hungary, Silesia, Saxony, Tyrol, Oberstein ;<br />
and as boulders of splendid specimens in Ceylon, Siberia,<br />
and Brazil. It is wrought in the same manner as rock<br />
crystal, being cut on a copper wheel with emery, and pol-<br />
lished on a tin plate with rotten stone. In order to raise<br />
its lustre, many facets, and very frequently those of a rose-<br />
diamond, are given to it in cutting.<br />
It is sometimes cut in"<br />
the form of a brilliant, and when set is supplied with a blue<br />
or red foil, provided the amethyst is pale, for the deep-<br />
colored ones do not require any artificial assistance. It is<br />
used in almost every description of jewelry, such as rings,<br />
ear-rings, and breastpins ; but it is set in necklaces to<br />
the best advantage, and is the only colored gem which<br />
may be worn with mourning, an advantage<br />
which adds<br />
'to its value. The amethyst is no longer held in such<br />
estimation as formerly, but the color, when intense and<br />
uniform, as also the size, contribute greatly to its value ;<br />
and good well-cut amethysts, of one carat, are worth from<br />
three to five dollars, and so on, in proportion to their size ;<br />
an amethyst fifteen lines long and eleven lines broad, ex-<br />
quisitely fine, was valued at five hundred dollars.<br />
The best amethysts now in commerce come from Cey-
268 A POPULAR TREATISE ON GEMS.<br />
Ion, Siberia, and Brazil; the first are commonly called<br />
Oriental amethysts, which, however, must be carefully<br />
distinguished from a much more valuable gem, the true<br />
Oriental amethyst, which is the violet<br />
.sapphire. I have<br />
in my collection a quantity of the Brazilian amethysts,<br />
which are of an intense violet color, and of a very large<br />
size.<br />
Amethysts occur also at Pic Bay, and at Gorgontwa, Lake<br />
Superior, crystallized in trap ; also at Bristol, Rhode Island,<br />
and occasionally throughout the trap region of Massachusetts<br />
and Connecticut.<br />
The amethyst, is valued by the jeweller in proportion<br />
to the dcpth r richness, and uniformity of its color, and<br />
its<br />
perfect transparency ;; it . forms,<br />
then,<br />
a stone of ex-<br />
quisite beauty, its color being, perhaps, more generally<br />
attractive than that of any other gem, especially as it may<br />
be obtained of as large a size as can be conveniently worn.<br />
It is worn by priests, bishops, and pontifical dignitaries-<br />
as a ring-stone set with brilliants. Like many other stones,<br />
it is less brilliant by candle-light, and it appears at all<br />
times to best advantage when surrounded with pearls and<br />
set in gold.<br />
Amethyst has lately been employed by the cameo-cutters<br />
of Paris, for cameos and intaglios ; the head is cut at the<br />
collet, which is the thick part of the stone, and the crown<br />
having diamond facets produces a fine effect.<br />
The is amethyst often imitated by fluor spar or violet-<br />
blue lime spar; both, however, are softer than amethyst ;<br />
the liine is lighter, and the fluor is heavier than amethyst.<br />
But it is imitated very strikingly by pastes, so that with<br />
great difficulty the real is to be distinguished<br />
from the<br />
imitation; the latter, however, is somewhat heavier, on account<br />
of the metallic oxides contained in the composition*<br />
The following is the best receipt for imitating the amethyst :
COMMON QUARTZ.<br />
1000 parts of strass,<br />
8<br />
"<br />
oxide of manganese,<br />
0'2<br />
"<br />
purple of cassius, and<br />
2G9<br />
.500 " oxide of cobalt,<br />
One of the largest geodes of amethyst was brought into<br />
England in 1819, weighing one hundred ami fifty pounds;<br />
it was two feet long and fourteen inches' broad, and con-<br />
tained most magnificent crystals, of the deepest violet color.<br />
On account of having been set down at too low a price at<br />
the custom-house, which was sixty-five pounds sterling, it<br />
was confiscated.<br />
COMMON QUARTZ.<br />
But a few varieties of the common quartz are used in<br />
jewelry, which are : the Rose Quartz, the Oafs-eye, the<br />
Prase, and the Avanturine,<br />
Rose Quartz,<br />
This mineral generally occurs massive; it is semi-trans-<br />
parent, and translucent on the edges ; has a vitreous lustre ;<br />
conchoidal and splintry fracture ; is of a rose-red color ; some-<br />
times giving a lustre of mother-of-pearl. It scratches glass;<br />
has a specific gravity of 2*64 to 2*67; its color, which is<br />
derived from the oxide of manganese, becomes paler before<br />
the blowpipe.<br />
Rose quartz occurs in gangues of granite and gneiss, par-<br />
ticularly fine in Sweden, Bavaria, Bohemia, and Siberia ;<br />
also a beautiful dark color in New-Hampshire and Massa-<br />
chusetts.<br />
Rose quartz is cut and polished for jewelry ; such as<br />
rings, breastpins, and snuff-boxes; it is cut on a copper<br />
wheel with emery, and is polished with rotten, stone and<br />
putty, on a tin plate, receiving the form of a cabochon or
270 A POPULAR TREATISE ON GEMS.<br />
table, and when set requires a foil, colored by carmine or<br />
solution of gold, as it fades when exposed a long time to<br />
the light. The rose quartz is not held in great estimation ;<br />
the color as well as the lustre of faded rose quartz may<br />
be resuscitated by being left for some time in a moist<br />
place.<br />
A vase of rose quartz was in the possession of the Marquis<br />
de Dree, nine inches high and two inches in diameter.<br />
Cat's-eye.<br />
The name of this mineral is derived from the peculiar<br />
play of light perceptible on its surface, by which it resem-<br />
bles the rays of light in the eyes of a cat ; it is not ascer-<br />
tained whether the ancients knew this mineral, and whether<br />
it was comprised in their .asterias; but it is well known that<br />
cat's-eye is in high estimation among<br />
the Malabars and<br />
Moors ; and it is worn throughout the whole East, where it<br />
is employed as an amulet, being believed to possess the virtue<br />
of enriching the wearer.<br />
Cat's-eye occurs massive, and in more or less roundish<br />
pieces ;<br />
has a. conchoidal fracture ;<br />
is translucent and trans-<br />
parent sometimes on one end ; it has a shining lustre,<br />
between vitreous and resinous ; gray and brown, green,<br />
red and yellow color ; it presents a peculiar floating light,<br />
which is particularly visible if cut in high cabochon, as it<br />
usually is when brought to market; it scratches glass; has<br />
a specific gravity of 2'56 to 2'73, and contains 95 silex,<br />
1*75 alumina, 1'50 lime, and 0*26 oxide of iron. In many<br />
specimens, there may be observed small parallel white<br />
fibres, which are supposed to be the cause of its peculiar<br />
play of light ; but the semi-transparent varieties, which<br />
are equally chatoyant as the more opaque ones, present<br />
no such appearance. This leads to the conclusion that
COMMON QUARTZ.<br />
27l<br />
amianthus in its finest fibres occasions the phenomenon,<br />
and the chemical analysis of the latter corresponds with<br />
the additional constituents of the cat's-eye. By exposure<br />
to a strong heat, it loses its lustre and transparency ; and,<br />
in' small fragments, is fusible before the blowpipe. Cat's-<br />
eye is found in fragments of gangues and boulders, of<br />
very small size, never larger than a hazel-nut, in Ceylon,<br />
on the coast of Malabar, in the Hartz mountains, Bavaria,<br />
and in this country, (in Vermont, New-York,
272 A POPULAR TREATISE ON GEMS.<br />
more probably he alluded to the emerald ;<br />
for the same min-<br />
eral is at the present time called the emerald mother or<br />
matrix by jewellers.<br />
it has a conchoidal fracture ;<br />
Prase occurs massive and crystallized;<br />
is translucent on the edges ;<br />
between vitreous and resinous in lustre ; and of a garlic-<br />
green color, the cause of which is, that actinolite is intermixed<br />
with the silex. It scratches glass ; has a specific gravity<br />
of 2-66 to 2-88, and is composed of silex, alumina, and<br />
oxides of iron and manganese. It is found in Saxony, Tyrol,<br />
Styria, Hartz, and the island of Elba. It is used for rings<br />
and pins ; also for snuff-boxes and other jewelry, and is cut<br />
in cabochon, and set with a gold foil at the base, by which<br />
its color is heightened, and rendered more agreeable.<br />
It is<br />
used in mosaic works, for foliage ; and likewise in the<br />
mounting of rubies, in order to raise their -color. Prase does<br />
not stand in great estimation ;<br />
for although it assumes a very<br />
good polish, it loses the same on long ^exposure to the air,<br />
and grows spotty.<br />
Avanturine.<br />
This mineral received its name from bearing a resemblance<br />
to a glass paste, formerly manufactured in<br />
Italy.<br />
It is a<br />
brown or red quartz, which is massive and translucent, or<br />
opaque ; it has a resinous lustre, and its fracture is splintry<br />
and uneven ; it is penetrated with gold or brass-yellow glistening<br />
fissures, caused by the refraction of light, or by innumerable<br />
mica leaves. It scratches white glass ; has a specific<br />
gravity of 2 '64 to 2 '68 ;<br />
are its constituents.<br />
silex, with some alumina and water,<br />
The avanturine is. found in the Uralian mountains, Styria,<br />
&c. It is<br />
Cape de Gata, near Madrid, Nantes, Scotland,<br />
used "for ring-stones, ear-rings, and snuff-boxes. It is cut<br />
on a copper wheel, with emery, and polished with rotten-
JASPER. 273<br />
stone on a tin plate ; it is cut semi-lenticular or oval, does<br />
not take easily a good polish, but may be improved by<br />
rubbing the stone with oil of almonds* The value of avan-<br />
turine is much depreciated of late, and its imitation by glass<br />
paste, called goldstone, is by far superior to the real stone,<br />
which has nothing but hardness in its favor. This paste is<br />
manufactured in great quantities in France, by throwing the<br />
finest impalpable powdered brass into a quantity of colorless<br />
strass, or into a composition of<br />
105 parts quartz,<br />
85 "<br />
purified potash,<br />
230 "<br />
tin and lead alloy><br />
50 "<br />
brass powder.<br />
The artificial avanturine, as made in Italy, is a silicious<br />
oxide of copper. The mode of<br />
manufacturing<br />
the best<br />
quality, which is done very extensively in Italy and France,<br />
is still kept a secret ; that the copper is reduced first to a<br />
sub-oxide, and nearly to its crystalline metallic state, may<br />
be inferred on examining with a microscope the common<br />
artificial stone, which has a most splendid appearance*<br />
The best ananturine is manufactured in Venice, by M. P.<br />
Bibaglia, who alone appears to have the secret of excelling<br />
the natural stone. Messrs. Fremy and Ckmendot, expert<br />
French chemists, have succeeded in approximating the Ve-<br />
netian manufacture, by heating 300 parts ground glass with<br />
40 parts of protoxide of copper and 80 parts of oxide of<br />
iron, and allowing the mass to cool very slow.<br />
Large blocks of the factitious avanturine, with a great<br />
variety of manufactured ornaments, were admired in the<br />
Paris Exhibition, in 1855.<br />
JASPER.<br />
This mineral is of Oriental origin, and is very often men-<br />
tioned in the Bible. *<br />
It was the sixth stone in the plate of<br />
12*
274 A POPULAR TREATISE ON GEMS.<br />
the high-priest. Jasper was well known to the Greeks and<br />
Romans, and according to Pliny, who has described sev-<br />
eral varieties, the best came from Scythia, Cypria, and<br />
Egypt, on the banks of the Nile. The lapidaries formerly<br />
made use of it in their works, particularly the Egyptian<br />
jasper, which afforded them abundant material. The column<br />
of Memnon and the foundation of the column of Pom-<br />
pey were constructed of it, and we find daily, among the<br />
excavations of Herculaneum and Pompeii, fragments of ruins,<br />
composed of Egyptian jasper.<br />
has a conchoidal frac-<br />
Jasper occurs in enormous masses ;<br />
ture ; is opaque ; its lustre is<br />
slightly resinous, like wax,<br />
often dull ;<br />
it is of white, red, yellow, green, blue, brown and<br />
black colors ; it scratches glass, but yields to rock crystal ;<br />
its specific gravity is 2-31 to 2*67.<br />
It is usually found in gangues, seldom in strata, in Egypt,<br />
Bohemia, Saxony, Tyrol, Hungary, France, Italy, Spain,<br />
Siberia, Corsica ; in the United States, principally in<br />
Florida, North Carolina, Massachusetts, &c. ; also, in Nova<br />
Scotia.<br />
A fine yellow jasper is found at Vourla, bay^of Smyrna,<br />
in a low ridge of limestone, to the right of the<br />
wateringplace,<br />
between the harbor and the high hills that commence<br />
their rise about a mile back ; it is here associated with a<br />
beautiful opal, coarse carnelians, chrysoprase, and hornstone,<br />
and these minerals seem to occupy in the limestone<br />
the place of the hornstone, which is found in various parts of<br />
the adjoining country, and also at Napoli di Romania, in<br />
Greece. The plains of Argos are strewed with pebbles of red<br />
Jasper.<br />
The jasper and quartz rocks of Siberia am well known<br />
materials of extreme hardness, worked only in the Russian<br />
empire, and are rarely met with, except as imperial presents<br />
to princes and distinguished foreigners. A group of
JASPER. 2*75<br />
very remarkable objects was exhibited among the Russian<br />
goods in the London Exhibition. The material of some of<br />
these vases is quartz rock, but most are of a kind of pseudo<br />
jasper or pseudo jasper lava, of greenish color, and extreme<br />
toughness and hardness, resisting almost every tool, and<br />
requiring to be cut with emery, like the hardest gems.<br />
These rocks chiefly exist in Siberia, beyond the Oural, and<br />
are in great abundance and variety. The vases of jasper<br />
were worked at the imperial manufactories of Ekaterinen-<br />
burg and Kolyvan. There almost the whole work is performed<br />
by manual labor ; the only machine used is a simple<br />
lathe, on which the object to be turned is placed, and<br />
worked by iron tools and emery. No tool will touch these<br />
stones, both chisels and files of the hardest temper turning<br />
without producing any effect. The time 'for furnishing<br />
vases of considerable magnitude is often many years, and<br />
their value is calculated by the cost of the large establish-<br />
ment kept at constant work. A large vase, measuring three<br />
feet on each side, in a square form, was exhibited, hollow<br />
under the rim, with foliage in the same, and was one of the<br />
great curiosities in the Exhibition. Smaller vases, an olive-<br />
green jasper urn, decorated' with admirably worked foliage<br />
in relief, from the imperial manufactories, were -likewise<br />
exhibited, all of which excited the admiration of the spectators;<br />
and since the times of the Greeks and Romans no such<br />
gigantic works, both in dimensions and weight, have been<br />
wrought. The quantity of intaglios and cameos from the"<br />
ancient Greeks and Romans is too numerous for giving them<br />
a space in this treatise, for it would fill a whole book to spe-<br />
cify the antiques which are scattered around the world, in<br />
the various museums of Rome, Vienna, Paris, London, Ber-<br />
lin, Dresden, and the private cabinets which have for centu-<br />
ries existed in noble families.<br />
According to their varieties, which are very numerous
276 A POPULAR TREATISE ON GfEMS.<br />
that is, in color and structure they receive their names \<br />
but they may still be classified into the following two-<br />
divisions :<br />
1. Egyptian Jasper, (Egyptian pebble,) which occursin<br />
spheroidal pieces,, of a gray-brown and red color, the-<br />
form of which is cut and polished in annular represen-<br />
tations around its centre. It is found in Baden, tip-<br />
of the<br />
per Egypt, and other places ; among the pebbles<br />
river Nile it is<br />
frequently discovered ; and in the year<br />
1714, it was found near the village of Inch eric; by Paul<br />
Lucas.<br />
2. Ribbon or Striped Spar. It occurs in masses, with<br />
nearly conchoidal fracture, around which parallel, straight,.<br />
or twisted stripes of a gray, green, yellow, red, or brown<br />
color may be perceived ; it is principally found in Siberia,<br />
the East Indies, Corsica, Tyrol, and the Hartz mountains ;<br />
some of the West India islands produce most splendid spe-<br />
cimens.<br />
Jasper is principally used for seals, snuff-boxes, vases,<br />
table-plates, and for some architectural purposes.<br />
When in lumps, it is divided by means of copper saws<br />
and fine sand, and then cut on copper or leaden wheels<br />
with emtfry, and polished on tin plates with rotten stone,<br />
on wood<br />
colcothar, or charcoal ; or it may first be polished<br />
with pumice stone, and lastly on a tin plate with rotten stone<br />
and water.<br />
The yellow jasper is often employed in mosaic works in<br />
Italy, and the striped jasper as cameos. Jasper- has no<br />
great value in trad-e, unless it be of exquisite quality, and<br />
fine objects be made of it. It generally commands the<br />
best price in China, where the emperor has a. seal cut of<br />
it. A vase of red Jasper, with white veins, and one of<br />
black jasper, with yellow veins, may be seen in the Vatican.<br />
Chatouilles and other boxes of considerable size
CHALCEBONt,<br />
are frequently fotmd in the jewelry stores of France, Eng-<br />
land,- and the United States,<br />
HORNSTONE,<br />
Hornstone occurs massive, globular, stalactiform, and in<br />
pseudo-morphous crystals of carbonate of lime, and also in<br />
the form of petrified wood, (wood-stone or agatized wood.)<br />
Its fracture is either conchoidal or splintry ; it is opaque or<br />
transparent on the edges; has a dull or shining lustre;- deep<br />
gray, brown, red, yellow, or green, and rarely a pure color.<br />
Often it has several colors in one and the same specimen,<br />
such as points, spots, and stripes. It scratches glass, and<br />
has a specific gravity of 2 '53 to 2 '65.<br />
It is mostly found in the gangues of the older formation J<br />
also in the old red sandstones and alluvial formations, in<br />
Bohemia, Saxony, Sweden, Siberia, Hungary, and a number<br />
I<br />
of other places ; in the old red sandstone of Thuringia.<br />
have traced one stem of the red agatized wood eighteen feet<br />
in length and two feet in diameter. The price of hornstone<br />
is very low ;<br />
it is used for snuff-boxes, seals, crosses, mortars,<br />
and principally as knife and fork handles. It is now used<br />
by silversmiths to mount butter and dessert knives and forks,"<br />
which are imported from Germany in considerable quan-<br />
tities-.<br />
CHALCEDONY.<br />
This mineral was held in great estimation by the ancients,<br />
who received their principal supplies from Egypt and other<br />
parts of Africa. In Rome, much use was made of it for<br />
cameos, many of which may yet be seen in collections. The<br />
inhabitants of Iceland are likewise said to value it very<br />
highly, and to attribute many medicinal properties to it*
278 A POPULAR TREATISE ON GEMS.<br />
It is found in crystals, such as cubes, but mostly massive,<br />
botryoidal, stalactiform, globular, or reniform, &c. The<br />
fracture is even, sometimes running into conchoidal or<br />
splintry ;<br />
it is semi-transparent<br />
or translucent,<br />
of little<br />
lustre, or dull ; of white, gray, blue, yellow, brown or green<br />
colors, which are all of a light shade, and variously figured,<br />
striped, spotted, &c.<br />
It scratches white glass, and has a specific gravity of<br />
2'58 to 2*66. It is distinguished into the following varieties,<br />
viz. :<br />
1. Chalcedony proper, or chalcedony x, wherein white and<br />
gray stripes alternate with each other.<br />
2. Mocha, or tree stones, are such chalcedonies as display<br />
black, brown, or red dendritical figures,<br />
3. Rainbow, or agate chalcedony, is chalcedony of thin<br />
and concentric structure, which, cut across and kept towards<br />
the light, displays an iridescence.<br />
4. Cloudy chalcedony, has a light gray and transparent<br />
base, with dark and cloudy spots.<br />
5. Plasma, dark grass-green. This mineral was very often<br />
employed by the ancients for cutting.<br />
6. Semi-carnelian, or ceregat, is generally called the yellow<br />
chalcedony.<br />
7. Sappharine, is the sky or sapphire blue chalcedony.<br />
8. St. Stephen's stones, is the white chalcedony, with<br />
blood-red spots.<br />
There are many more varieties, and in my own collection<br />
I have polished chalcedonies, among which, perhaps,<br />
as many<br />
again may be enumerated.<br />
Chalcedony was originally procured from Chalcedon, in<br />
Asia Minor, whence its name.<br />
Chalcedony is found in gangues, and in the cavities of<br />
Localities exist<br />
many rocks ; also in boulders and pebbles.<br />
in Saxony, Hungary, Faroe Islands, Ceylon', on the shores
279<br />
of the Nile, in Nubia, Nova Scotia, the UnUed States, (in<br />
Connecticut, Massachusetts, Pennsylvania, Ohio, New-Jersey,.<br />
Missouri, Florida,) and in other countries; but the best<br />
specimens are brought from Oberstein, Iceland, and the<br />
Faroe Islands.<br />
The finest specimens are employed in jewelry, for rings,<br />
pins, bracelets, necklaces, and seals; -the more common for<br />
snuff-boxes, vases, buttons, &c. The larger masses are cut<br />
by means of a copper wire, with emery and oil on a copper<br />
wheel ; they are polished on a tin plate with rotten stone,<br />
putty-powder, and pumice stone. The cutting is generally<br />
done on a large scale, like that of agate. Many are susceptible<br />
of receiving figures artificially, by means of the nitrate of<br />
silver. By Oriental chalcedony is generally understood the<br />
better qualities ; those chalcedonies of two or three divisions,<br />
called onyx, are used for cameos.<br />
The value of the chalcedony depends on its<br />
quality, such<br />
as purity, color, and the figures and drawings displayed on<br />
it ; and among all the varieties of chalcedony, the mocha<br />
stone stands the highest in price, and also the onyx, which<br />
is principally employed for cutting cameos, and according<br />
to its size, commands a high or low price. Mocha stones<br />
are sold in France at from five to eight francs. The cabi-<br />
net of Dresden contains a plate of onyx, about three inches<br />
broad and long, which is estimated at twenty-five thousand<br />
dollars.<br />
CARNELIAff.<br />
This stone was known to the ancients by the name of Sarda ;<br />
which, according to some, is derived from a place in Lybia<br />
or Sardinia, or, according to others, from the Arabic word<br />
sarda, meaning yellow; it has been employed very frequently<br />
for cutting intaglios or bas-relief gems.<br />
Carnelian occurs massive or in pebbles ;<br />
its fracture is con-
280 A POPULAR TREATISE ON<br />
choidal ; lustre resinous ; it is semi-transparent and translu-<br />
cent; of a blood-red, yellow-brown, or yellow color; fre*<br />
quently dark at the outside* growing paler<br />
side ;<br />
the colors are sometimes changing striated ;-<br />
towards the in-<br />
it scratches<br />
white glass, and has a specific gravity of 2-59 to 2 '63. There<br />
are two varieties known by lapidaries and jewellers which<br />
are better than the others; those having a pale color or yel-<br />
lowish tinge, and those having a dark-red color; the latter<br />
are in the highest estimation, and are called by the French<br />
cornalines de vieille roche.<br />
Sardonyx is called a carnelian, having as its principal color<br />
tne dark-brown or orange-yellow, interchanged with layers<br />
of a white color.<br />
Carnelian onyx has a blood-red base, marked with white<br />
stripes. The finest carnelians come from Siberia, India,<br />
Arabia, Nubia, Surinam, Oberstein in Germany, and Tyrol ;<br />
they occur mostly as pebbles or in .cavities of^ rocks. In the<br />
United States they are found on Lake Superior in large<br />
quantities, in Missouri, and in Massachusetts. The carne-<br />
lian is used for numerous articles in jewelry, such as seals,<br />
it is cut on a leaden plate with<br />
rings, watch-keys, &c. ;<br />
emery, and is polished on wood with pumice stone,<br />
and ob-<br />
tains its highest polish on a plate composed of lead and tin<br />
with rotten stone and water. The form of its cutting is<br />
that of pavilion or step cut, on the upper part, and either<br />
quadrangular, hexagonal, octangular, or round ; and for<br />
raising its lustre or color it is furnished with a, silver or<br />
gold foil, or with red paint on its base. The color of th<br />
carnelian is also improved by calcination ; the yellowish<br />
it in a moderate heat and<br />
kind, for instance, by calcining<br />
cooling.it slowly, may assume a good red color. It is said<br />
that the ancients boiled the carnelian in honey in order to<br />
heighten its- color. Colored figures or drawings may suc-<br />
cessfully be represented by a mixture of white-lead, colco-
CARNELIAN. 281<br />
thar, or other metallic oxides, and gum-water, which is the<br />
material for drawing on it, and by burning the same under a<br />
muffle.<br />
Carnelian is divided into Oriental and occidental ; the first<br />
is found in the old rocks, and is generally very hard, rich in<br />
color, clear and transparent, and takes a high polish, is<br />
brought from Surat, in the Indies, and valued at ten francs the<br />
kilogramme ; the occidental carnelian is softer, of a yellower<br />
red and less brilliant.<br />
Stygmite is a beautiful variety with variegated colors, of<br />
reddish-yellow or yellowish-red, with many white lines passing<br />
through the stones.<br />
The ancients, particularly the Romans, were very partial<br />
to engraving on carnelian, and some very remarkable stones<br />
are still in existence in the imperial library at Paris. The<br />
seal of Michael Angelo, which is valued at 50,000 francs,<br />
is said to have been engraved by Maria de Descias after<br />
the original of Praxiteles ; the bust of Ulysses, Hercules<br />
killing Diomede, Jupiter, Mars, and Mercury.<br />
The great scarabee in carnelian, in the Prussian cabinet,<br />
which represents the five heroes of Thebes, is a master-piece<br />
of Etruscan art.<br />
The crown jewels of France contain some very costly car-<br />
nelian engravings of very large size.<br />
The faults of the carnelian are fissures, unequal color, and<br />
flaws from other stones. Carnelian is, on account of its<br />
being less brittle, more useful for engraving and cutting<br />
cameos ; the white layers are generally used for the figures<br />
of cameos and' the red for the base. Sometimes such<br />
carnelians as are cut with bas-relief objects, are filled out<br />
with colored strass ; and we receive from India, very fre-<br />
quently, cameos with the most singular drawings, and which<br />
are made by the inhabitants in the following manner : the<br />
whole carnelian is covered with carbonate of soda, and then
282 A POPULAR TREATISE ON GEMS.<br />
exposed to the fire for a few minutes, whereby a strass is<br />
formed, upon which the figures<br />
are cut. The value of carnelian<br />
is much higher than chalcedony, but yet depends on<br />
all its qualities of color, transparency, equal division of color,<br />
and freedom from faults, such as fissures, clouds, dark spots,<br />
&c. For a perfect sardonix, a is very high price generally<br />
given, particularly when the layers are very distinct and<br />
run quite parallel, and are pretty thick, so that they are<br />
fit for cutting cameos or intaglios. The blood-red is second<br />
in value, and the pale-red third ; but the cheapest are the<br />
yellowish, brownish, or whitish kinds ; the prices vary from<br />
twenty dollars to twenty cents per piece. There exists a<br />
cameo of sardonyx, representing the portrait of the celebrated<br />
Father Fontanarosa, having his face white, with the base,<br />
show the<br />
cap, and cloak black, so that it may distinctly<br />
Dominican monk.<br />
HELIOTROPE, BLOODSTONE.<br />
This stone derives its name from the Greek language,<br />
having been used in ancient times for observing the sun.<br />
Pliny speaks of heliotrope. It occurs in massive and<br />
obtuse angular lumps, of a conchoidal fracture, is trans-<br />
lucent on the edges, of a resinous lustre, and leek-green<br />
It scratches white glass ;<br />
color, with red and yellow spots.<br />
has a specific gravity of 2*61 to 2'63. Heliotrope is<br />
found among amygdaloid, in Tyrol, in the United States,<br />
(in New-York, near Troy,) Scottish Islands, Siberia, Faroe<br />
Islands, Egypt, Barbary, Tartary, &c. It is principally<br />
employed in rings and seals, watch-keys, snuff-boxes, and<br />
other articles of jewelry, also for sword and dagger han-<br />
dles ; and is wrought like chalcedony, but sometimes cut<br />
on brass plates ; its forms are various : as cabochon and<br />
pavilion.
AGATE. 283<br />
Heliotrope has been greatly admired in modern times ;<br />
its pric'e depends upon the color and quantity of red spots<br />
contained in ft. From one to twenty dollars is the usual<br />
price for good and large specimens.<br />
It is said that superstitious people in the middle ages<br />
valued the<br />
heliotrope, with many red spots, very highly,<br />
thinking that Christ's blood was diffused through the stone.<br />
AGATE.<br />
This stone was well known to the ancients, under the<br />
name of achates, and was used for various purposes of jewelry.<br />
In Rome, it was principally used for cutting cameos<br />
from the striped kind, the onyx. It has also been worn as<br />
an amulet, with different characters engraved upon it. Its<br />
name is derived from a river in Sicily, where the ancients<br />
procured it. Agate is a mixture of several species of quartz,<br />
which are variously combined ; chalcedony or carnelian<br />
usually forms the principal part, and is mixed with hornstone,<br />
jasper, amethyst, quartz, heliotrope, cachelong, and<br />
flint; and according to the predominating substances, it is<br />
sometimes called chalcedony, jasper,<br />
or carnelian agate.<br />
Its<br />
color, as well as its other characters, depends upon the na-<br />
ture of the mixed parts ; likewise its hardness ; but it usually<br />
scratches white glass, and has a specific gravity of 2*58 to<br />
2-66 at the utmost.<br />
According to the different figures represented in agate, it<br />
receives its various names.<br />
1st. Ribbon, or striped agate, representing layers vari-<br />
ously colored, and alternating with one another. Onyx,<br />
or agate onyx, are such agates as have the colors beautiful<br />
and distinct, and whose layers run in a parallel direction<br />
with the larger surface ; whereas the common ribbon agates<br />
display their various layers on the surface, without being
284 A POPULAR TREATISE ON GEMS.<br />
parallel. If the stripes run together around the centre, it<br />
is called the circle agate, and if in the same stone the<br />
centre shows more colored spots, it is called the eye agate,<br />
or eyes tone.<br />
2d. Fortification agate is that brownish agate, the vari-<br />
ous colored stripes of which run in a zig-zag, or irregular<br />
lines and angles, representing the ground plan of fortifica-<br />
tions.<br />
3d. Rainbow agate ; the curved stripes have the property<br />
of displaying rainbow colors when held towards the sun,<br />
or candle-light, and the more distinctly if the stone is cut<br />
very thin.<br />
4th. The cloud, landscape, dendritic, figure, moss, punctated,<br />
star, petrifaction, shell, coral, tube, fragment, and ruin<br />
agates are all the various forms in -which the is agate dis-<br />
played, according to its figure or drawing. A ruin or fragment<br />
agate may be pasted together from the fragments of<br />
a common ribbon agate, so as to make it represent old<br />
walls, whereby it receives the name of breccia agate ; sometimes<br />
the rainbow agate occurs in connection with the shell<br />
agate, where the moss surrounding the petrified<br />
shells forms<br />
the rainbow agate.<br />
The royal collection at Dresden contains a table service of<br />
German agate; at Vienna, in the imperial cabinet, there .is<br />
an oval dish twenty-two inches in length, formed from a sin-<br />
gle stone.<br />
The achates of the Greeks were so called from the river<br />
Achates, in Sicily, whence, according .to Theophrastus, these<br />
stones were originally brought.<br />
J asp achates corresponds to our jasper agate ; sardachates<br />
contained layers of the sarda, or carnelian ; dendrachtes,<br />
from &evtpov, a tree, corresponding to our moss agate ;<br />
hsemachates, from d^a, blood, which was an agate sprinkled<br />
with spots of red jasper.
AGATE. 285<br />
Among the crown-jewels of France, is a very valuable set<br />
>f agates, ten cups and sa.ucers, four urns, four chandeliers,<br />
four busts, two ewers, two basins, two vases, two bowls, two<br />
salvers, one decanter, and one candlestick ; the whole set is<br />
valued at 500,000 francs.<br />
At the French Exhibition in 1855, a magnificent Oriental<br />
agate, by Froraent Maurice, belonging to the Princess<br />
Mathilde, was exhibited, having the engravings<br />
of the<br />
three infatuations,<br />
the amorous, the poetical and sad, most<br />
tastefully represented. It is the Benvenuto Cellini of our<br />
day.<br />
The most celebrated cameo in Oriental agate, is the bust<br />
of Alexander the Great, which is a perfect gem ;<br />
the head is<br />
quite independent in color froin the base of the stone, and<br />
the execution without a blemish.<br />
The Orleans collection contained two agates : one repre-<br />
senting the death, of Cleopatra, as a half-body ; the other,<br />
Lysimachus, the head girdled with a diadem.<br />
A large black agate, particularly remarkable for its<br />
perfec-<br />
tion and .the complication of its workmanship, represented<br />
a captive followed by two generals on horseback, and<br />
several other persons, one showing a trophy, and another a<br />
laurel branch,<br />
An intaglio of Neptune, belonging to the Sabatini Museum,<br />
was also exhibited.<br />
Agate is found in gangues, in gneiss, porphyry, or amygdaloid<br />
; also, as boulders and pebbles, in rivers, &c. It<br />
is found in Baden, Oberstein, Saxony, Bohemia, Hungary,<br />
the Faroe Islands, Siberia, the West Indies, and in the<br />
United States, (Massachusetts, Rhode Island, New Jersey,<br />
Indiana, Missouri, Maryland, Georgia.) Those occurring- in<br />
amygdaloid are mostly in the form of geodes, or balls,<br />
hollow inside, and coated with quartz or amethyst ; when<br />
the rock begins to disintegrate, these balls, becoming
286 A POPULAR TREATISE ON GEMS.<br />
loose , fall scattering around the soil, and are then collected<br />
by persons who make a business of either selling or cutting*<br />
them.<br />
The agate is used not only for various purposes of<br />
jewelry and ornaments, such as seals, snuff-boxes, crosses,<br />
cases of various descriptions, ear-drops, &c., but also for<br />
numerous other useful purposes, on a large scale ; such as<br />
slabs, mortars, vases, instruments, knife and fork handles,<br />
playballs, &c. The manufacturing of th^m forms a considerable<br />
branch of<br />
industry in a<br />
part of Germany. The<br />
agate, after having been reduced to suitable sized pieces,<br />
by means of a saw, chisel or hammer, is then cut on a<br />
copper wheel by means of emery, powdered garnet or topaz,<br />
and is afterwards polished on a tin plate with rotten stone,<br />
putty or pumice stone.<br />
Oberstein, a small place in 'Rhenish Bavaria, in the north<br />
of Germany, has five large manufacturing establishments<br />
for the sole purpose of<br />
cutting and polishing the common<br />
gems or semi-precious stones, and it is the only place where<br />
this branch of business is carried to any great extent.<br />
Twenty mills are constantly driven by water, and more<br />
than one hundred thousand dollars worth of work is turned<br />
out yearly for export ; a sum which is small in comparison<br />
with the enormous quantity of goods manufactured and set<br />
afloat, but pretty considerable for such places, where labor<br />
is so cheap, and the best of workmen may be had for one<br />
dollar and fifty cents per week. At Oberstein the business<br />
is divided into two branches; the one is devoted to the<br />
cutting and polishing of the agate,<br />
and the other to the<br />
boring ; the workmen are called agate lapidaries and agate<br />
borers. The cutting is performed in the large agate<br />
mills, on sandstone ; each mill has generally five large<br />
sandstones, five feet in diameter and fourteen to fifteen<br />
inches in thickness, fastened upon a shaft, ^which causes
AGATE. 287<br />
them to revolve vertically, and which are<br />
continually<br />
moistened by a stream of water. The workman leans with<br />
his. body upon a peculiar bench, the seat of which is called<br />
the cuirass, and with his feet presses himself against a pole,<br />
whence he continually pushes the larger lumps of the agate<br />
towards the rnill-stotoe ; this, however, is often made so<br />
smooth from the friction, that it is often necessary to make<br />
it rough by knocking it with a sharp hammer, according to<br />
the kind of work, whether fine or coarse. The stones are<br />
either polished on sandstone or on wood, by means of fine<br />
clay or powdered chalk ; they are polished sometimes, also,<br />
on wooden wheels, covered with lead or tin. Snuff-boxes<br />
and other articles of agate, which are hollow, are polished<br />
on smaller sandstone wheels, which dimmish in size as the<br />
work advances. Agates which require to be bored belong<br />
to a particular branch, distinct from the other. The boring<br />
is performed by means of a diamond point, and is described<br />
by Mr. Mawe. The onyx varieties are mostly employed<br />
for cutting cameos, and are prepared there in such a manner<br />
that the darker layer is cut for the base, and the lighter for<br />
the intended objects.<br />
There is in Siberia, at Katherineburgh, an extensive<br />
manufactory for grinding and polishing agate<br />
and other<br />
gems.<br />
Many varieties of agate are used for engraving other<br />
stones, and also for the Florentine or stone mosaic work.<br />
Since agate has always been, and is<br />
yet, a favorite. stone,<br />
it has been attempted to improve either its color or other<br />
"external appearance by artificial or mechanical means ; this<br />
is done either by the use of metallic solutions or by boiling<br />
in oil of vitriol. The color has often been improved by<br />
giving to the stone, before it is polished,<br />
several strokes in<br />
succession, the small fissures thereby produced displaying<br />
an iridescence or some other phenomenon, if held towards
288 A POPULAR TREATISE ON GEMS.<br />
the light 5 this operation, liowev.er, may easily<br />
be detected<br />
by wetting the stone, when the water, entering the fissures,<br />
will destroy the effect; it will show itself again when dry.<br />
On some agates black and white layers are produced, in<br />
order to use or sell them in the place<br />
of real onyx this<br />
;<br />
who boil certain<br />
operation is performed by the lapidaries,<br />
varieties in oil of vitriol, which changes the color of some<br />
very soon to black, and renders others clear or still paler.<br />
Only polished agates are used for this purpose, and the cause<br />
appears to lie in the oil absorbed by them during the operation<br />
of polishing, on which account agates are by some first<br />
boiled in oil before submitting them to the operation of the<br />
oil of vitriol.<br />
The value of agate, although much reduced in com-<br />
parison to former days, a great deal depending upon the<br />
purity and perfection of color and peculiar figures, commands<br />
a pretty good price in the market ; it is particularly<br />
the onyx which is yet at high prices, and on that account it<br />
is imitated by pasting thin plates of chalcedony, jasper, agate,<br />
&c., together, and making them, by their different colors,<br />
appear like real onyx ; this deception may, however, be easily<br />
detected by it putting into hot water, which disengages the<br />
plates one from another ; the onyx is likewise imitated by<br />
pastes, and very happily, but may readily be distinguished<br />
from them by the hardness and other characters prominent<br />
in the real stones.<br />
Onyx, which, as already stated, is a .variety of agate,<br />
and most frequently<br />
of chalcedony, possesses<br />
in its intrinsic<br />
characters a- regular<br />
alternation of layers, which are<br />
more or less thick, and of distinct different colors, usually<br />
the grayish white, brown, and black predominating ; while<br />
sardonyx indicates one layer or more to be of carne-<br />
lian, and this is in higher estimation. It was this stone par-<br />
ticularly which the ancients mostly sought after for engrav-
AGATE. 289<br />
ing the heads of celebrated persons, their deities, and their<br />
idols; the fawn-colored variety, which is neither yellow<br />
nor red, was the highest in value. Both onyx and sar-<br />
donyx were purchased in Arabia and the Indies, and the<br />
harder the stones and finer the grain, the more valuable<br />
they were for the purpose of cutting. The title of Oriental<br />
of the<br />
onyx was always given to the finest qualities<br />
stones, regardless of the locality from whence they were<br />
brtmght.<br />
The Imperial Library at Paris possesses some of the most<br />
antique cameos and intaglios of onyx,<br />
such as Germani-<br />
cus, Marcus Aurelius, Faustina, and Tiberius ; the dread-<br />
ful Jupiter is an onyx in two layers ; Venus on a marine-<br />
bull, surrounded by cupids, are personifications<br />
of the<br />
highest perfection in the art.<br />
The superb fragment existing in Rome, and representing<br />
Antilochus announcing to Achilles the death of Patrocles, is<br />
another master-piece ;<br />
the cameo has a* black ground, with<br />
a white layer above, and the expression of grief on the<br />
three faces has secured to this cameo the decided suprem-<br />
acy of the ancient over the modern art.<br />
The bowl of Capo di Monte, in the Royal Museum of<br />
Naples, and the great cameo of Alexander and Olympia,<br />
belong to Mr. Bracciano, at Naples.<br />
The French Museum contained the great cameo of An-<br />
tonius and Faustina, engraved in different colors, but not<br />
parallel lines, it is not inferior to any other : the ground,<br />
which is of agate of brownish color, is Antonius, and<br />
above, in a white layer, is the pleasant figure<br />
of Faus-<br />
tina, whose drapery and hair ornaments are exceedingly<br />
well executed in a lilac color.<br />
The sardonyx is also called sarde, and if of a dark sable<br />
color, was preferred by the ancients for cutting intaglios.<br />
Mars and Venus when surprised by the gods, is executed<br />
13
290 A POPULAR TREATISE ON GEMS.<br />
by Valerio Yicentine; it represented nine figures. The<br />
Nuptials of Cupid and Psyche contains .five figures.<br />
In the inventory of curiosities belonging to the crown of<br />
France, made in 1*791, are mentioned two vases of sardonyx,<br />
valued at sixty-four thousand francs ; six sets, at one<br />
hundred and sixty-seven thousand francs ;<br />
two cups at six-<br />
teen hundred francs; one decanter at thirteen hundred<br />
francs ; one urn at six hundred francs ; but one remarkable<br />
sardonyx, of a grayish yellow mixed with brown, on which<br />
a Medusa head was engraved, was valued at twelve thou-<br />
sand francs.<br />
The onicolo or nicolo is another variety of onyx ; it is<br />
of brown ground with a band of bluish white ;<br />
it is distin-<br />
guished from onyx, by the lower layer being always thinner<br />
than the upper it is not so ;<br />
highly valued as either the<br />
onyx or sardonyx. The Mineralogical<br />
Cabinet at Paris<br />
possesses several cameos of this material ; one represents<br />
military piety ; also a cameo of Adonis, by Coinus. The<br />
stone is probably the cegyptilla, described by Pliny.<br />
The real sardonyx is the rarest mineral among that class<br />
of stones, on account of the multiplicity of layers, of which<br />
there are as many as ten, all, however, from the same sub-<br />
stances, but differently colored : such as chalcedony, jasper,<br />
agate, white, gray, red, and brown, opaque, translucent,<br />
bluish, or yellowish; they are highly prized, particularly<br />
those from the Orient.<br />
The finest cameo of the real Oriental sardonyx is in the<br />
imperial cabinet of Vienna, it is said to come from Diosco-<br />
rides ; it was obtained by Rudolph II., the German emperor,<br />
for 12,0(70 ducats.<br />
In the crown-jewels of France are some unique cameos<br />
of sardonyx, such as the triumph of Bacchus and Ariadne,<br />
valued at 7000 francs, and eleven other cut stones valued<br />
together at 60,000 francs.
AGATE. 291<br />
Great collections of antique onyxes, engraved as cameos<br />
and intaglios, are in Vienna and Berlin; in the first is to<br />
be seen the apotheosis of Augustus, which is ten lines broad<br />
and six high, and contains twenty perfect figures this was<br />
;<br />
purchased by the Emperor Rudolph at Frankfort-oir-the-<br />
Maine, for fifteen thousand ducats.<br />
The celebrated cameo in the Vatican Museum, at' Rome,<br />
is of agate, and represents Augustus. Italy has always been<br />
the great emporium for genuine antique onyxes and cameos,<br />
and occasionally we still behold fine specimens of art in the<br />
.<br />
possession of travellers coming from Europe. A very fine<br />
collection of antique cameos and intaglios in precious gems<br />
and antique pastes, likewise cameos and intaglios of modern<br />
artists, I have seen in this country, in the possession of<br />
Thomas G. Clemson, Esq., of Philadelphia.<br />
I have in my collection a good onyx of the Emperor Vi-<br />
tellius ;<br />
a splendid cameo of Bacchus, of two and one fourth<br />
inches long and one half inch thick ;<br />
Cleopatra ;<br />
one of Antony and<br />
also a splendid intaglio.<br />
In Paris are several celebrated cameos, worthy the notice<br />
of travellers going to Europe : the Brunswick Vase was cut<br />
from a single stone, and has the form of a cream pot, about<br />
Iseven inches high and two and a half broad on its outside,<br />
which is of a brown color; there are white and yellow<br />
groups of raised figures, representing Ceres and Triptolemus<br />
in search of Proserpine; Agrippina and- her two chil-<br />
dren, composed of two layers, brown and white ;<br />
the Quar-<br />
rel of Minerva with Neptune, which consists of three layers ;<br />
Venus on a sea-horse, surrounded with cupids, &c.<br />
The Museo Borbonico at Naples contains an onyx meas-<br />
uring eleven inches by nine the apotheosis of Ptolemy on<br />
one side, and the head of Medusa on the other ; both are<br />
splendid specimens of art, and supposed to be the largest in<br />
existence.
292 A POPULAR TKEATISE ON GEMS.<br />
Two very beautiful flower-vases of black onyx, colored<br />
with natural white veins, two large cups of red chalcedony<br />
colored, long square links of chalcedony, connected together<br />
without joints, and alternating in colors, also a very beautiful<br />
snuff-box of green jasper, were seen at the London<br />
Exhibition, manufactured by Wild & Robinson, in Oberstein.<br />
Some modern works of cameo, from the hand of the cele-<br />
brated Puckler, are in the collection of Robert Gilmore,<br />
Esq., at Baltimore, and in that of W. J. Lane, Esq., of this<br />
city, who possesses also a Washington head of black and<br />
white onyx, by Isler, which is extremely beautiful; also a s<br />
very fine modern cameo in onyx, two inches in length, I<br />
saw in Stephen H. Palmer's establishment.<br />
CHRYSOPRASE.<br />
The ancients by this name designated a stone of a green<br />
but it is not certain whether<br />
color, with a yellowish tinge ;<br />
that which goes by this name, at the present day, is the<br />
same. We find, in the fourteenth century, this stone used<br />
as ornaments in churches and other places, but it was not<br />
known by the above name until 1740, when it was* discov-<br />
ered by a Prussian officer in Silesia. Frederick the Second<br />
ornamented his palace Sans Souci with this mineral.<br />
The common people of Silesia wear the chrysoprase<br />
around the neck as a charm against pains.<br />
Chrysoprase occurs massive and in plates ;<br />
the fracture<br />
is even and splintery; it is translucent; lustre, resinous;<br />
sometimes dull apple-green, grass-green, olive-green, and<br />
whitish-green color ;<br />
it scratches white glass distinctly, but<br />
is not so hard as true chalcedony; specific gravity, 2'56 ;<br />
it is infusible before the blowpipe, but loses its color when<br />
heated ; it consists of silex, with a little carbonate of lime,<br />
alumina, oxide of iron, and nickel ; its color is imparted by
CHRYSOPRASE. 293<br />
the latter substance. This mineral is found in the serpentine<br />
of Silesia ; also, in Siberia, and in the United States<br />
(in New Hampshire).<br />
Chrysoprase is used in jewelry and for various ornamental<br />
purposes, such as breastpins, rings, bracelets, necklaces,<br />
seals, &c. ; and the larger masses are used for snuff-boxes,<br />
cane-heads, table-plates, &c. The cutting is pretty difficult,<br />
and the greatest care is required for finishing the same<br />
with facets, as it is easily fissured ;<br />
it is done on tin or lead<br />
plates with* emery, keeping the first constantly<br />
wet with<br />
water ; it is polished on a tin plate with rotten-stone, but<br />
the lapidary has always to be cautious not to let it become<br />
hot, as it easily splirfters, and grows opaque and gray.<br />
The usual cut is the table or cabochon, with facets on the<br />
border ; in setting, a foil of green satin is often used for a<br />
back, but when pure and of good color, it is mounted djour.<br />
Inferior specimens are painted on the back with a mixture<br />
of verdigris, white lead, and gum mastic, or with sap-green.<br />
The chrysoprase loses its color by wearing; heat and<br />
sunlight likewise cause it to fade, and render it dark and<br />
cloudy ; but the color may be restored by keeping<br />
it in a<br />
wet or moist place, such as a cellar, in wet cotton or sponge,<br />
or even by dipping it in a solution of nitrate of nickel,<br />
which serves likewise to improve the inferior qualities.<br />
Very fine imitations in paste may be made by mixing<br />
1000 parts of strass with<br />
5<br />
"<br />
of oxide of iron, and<br />
8<br />
"<br />
of oxide of nickel.<br />
The chrysoprase is subject to a great many faults, such<br />
as fissures, either natural or received in cutting ; oily whitish<br />
spots, pale gray flaws and stripes,<br />
and sometimes small<br />
grains of clay of reddish color, intermixed in the interior of<br />
the stone ; but when pure, the chrysoprase has always been
294 A POPULAR TREATISE ON GEMS.<br />
a great favorite. A good seal or ring stone may be worth<br />
from twenty-five to thirty dollars, and smaller specimens<br />
from one to five dollars. The apple-green variety is most<br />
valued, and a specimen one line long by one half broad,<br />
has been sold at from fifty to one hundred and fifty dollars.<br />
At Paris, an oval chrysoprase, eight lines long and seven lines,<br />
broad, was- sold for three hundred and ten francs. The<br />
price generally has decreased of late, on account of the<br />
great quantity cut from the mines, which have recently<br />
been covered up, in order to raise its value again. At the<br />
royal palace of Potsdam, in Prussia, are two tables of chrys-<br />
oprase, the plates of which are three feet long, two feet<br />
broad, and two inches thick.<br />
CHRYSOLITE, PERIDOT, OLIVIN.<br />
The name of this stone is of Greek origin, and was well<br />
known to the ancients, although it is undecided whether<br />
they designated the same mineral by this name that we do<br />
at the present time, for they make it in their writings to be<br />
either the. topaz or goldstone, or the transparent gold-<br />
yellow stone.<br />
The chrysolite occurs in prismatic forms, generally a<br />
right prism with rectangular bases; also, in angular<br />
rounded crystalline grains or massive ;<br />
the fracture is conchoidal ;<br />
it is trans-<br />
parent and translucent; it possesses<br />
powerful double-refracting power ; its<br />
lustre is vitreous and resinous; the<br />
lateral planes of the crystals are some-<br />
times striated ; the color is olive-green,<br />
turning to yellowish and brownish;<br />
it scratches glass indistinctly, and is<br />
attacked by topaz ; hardness, 6'5 ;<br />
Fig. 10.
CHRYSOLITE. 295<br />
specific gravity, 3"33 to 3'44 ; becomes electric by rubbing ;<br />
is infusible by itself before the blowpipe, but is dissolved<br />
into a transparent pale-green bead with borax;<br />
acids do<br />
not affect it ; it consists of magnesia, silica, and oxfde of<br />
iron. Chrysolite is found particularly in basalt, trap, green-<br />
stone, porphyry, and lav% ; sometimes in alluvial deposits<br />
and the sands of rivers.<br />
The perfectly crystallized chrysolite is brought from<br />
Constantinople, but its true locality is unknown ;<br />
less dis-<br />
tinct crystallizations occur imbedded in Java at Vesuvius<br />
and the Isle of Bourbon ; imbedded in obsidian at Reel del<br />
Monte,. in Mexico; among sand at Expaillie, in Auvergne,<br />
in pale-green transparent crystals.<br />
Egypt, Natolia, and Brazil are the principal localities<br />
for the prismatic chrysolite; the oh*vin is more frequently<br />
found in imbedded crystals, and granular aggregations, in<br />
the basalts of the Habichtswald, the Eiffel, the Upper<br />
Palatinate, Geysingburg near Altenburg, Kapferistein. in<br />
and in the sienite at Elfaden in Sweden. The brown<br />
Styria,<br />
variety (hyalosiderite) is- found at Sabbach and Iringen on<br />
the Kaiserstahl, and hi dolorite, near Rpburg in Baden.<br />
Crystals of olivin, several inches in length, occur in green-<br />
stone, at Unkle near Bonn, on the Rhine, and it is a frequent<br />
ingredient of meteoric stones.<br />
The word chrysolite is derived from %pv0o$, gold, and<br />
/U0of, stone, in allusion to its color.<br />
The dark-colored peridots, which take a high polish, are<br />
now much worn in Europe ; they lose, however, their gloss<br />
very soon, on account of their softening.<br />
The ligurite is a species of chrysolite of an apple-green<br />
color, is transparent and of uneven fracture; hardness, 5 '3 ;<br />
specific gravity, 3*49. Its /4|kimary form is an oblique<br />
rhombic prism; the ligurite contains some alumina and<br />
lime in addition to the composition of the chrysolite ;<br />
it is
296 A POPULAH TREATISE ON GEMS.<br />
considered a superior gem to chrysolite, both in color and<br />
transparency. It occurs in a talcose rock on the banks of<br />
the Stura, in the Apennines of Liguria ; it does not become<br />
electrfc by heat or friction.<br />
The bot.tlestone of Moravia is likewise a species of chrys<br />
olite, of dirty-green and grayisto-green colors, does not<br />
occur crystallized, but in flat pieces of about an inch in size ;<br />
some specimens which the author collected in his youth, in<br />
Moravia, were fair specimens suitable for cutting, their<br />
color being dark-green.<br />
The chrysolite is cut on a leaden wheel with emery, and<br />
is polished on a tin plate with rotten-stone or oil of vitriol.<br />
Sometime^ pale stones are finally polished with some olive<br />
oil, which, raises the color considerably : this last operation<br />
is applied to restore its lustre, after the chrysolite becomes<br />
dull 'by wearing. The form is that ojf a rose or table cut ;<br />
also in pavilion ; and when set, gold foil is used for its base :<br />
the -pale-colored chrysolite looks well with a green-colored<br />
dark chrysolites may be rendered clearer by a<br />
copper foil ;<br />
careful calcination. +'.<br />
The chrysolite^ used for rings and pins, but does not<br />
stand in high estimation, not possessing either a distin-<br />
guished color, strong lustre, or great hardness, and losing<br />
its polish by wearing ; on account of its softness, it wears<br />
off at the edges. Very good specimens of peridot from<br />
Brazil were brought into this country from France, and<br />
commanded a good price, a few years ago, viz : from ten<br />
to fifteen dollars a carat.<br />
Chrysolite was much esteemed by the ancients ;<br />
Queen<br />
Berenice received a chrysolite as a present from Phile-<br />
mon, lieutenant of King Ptolomeus.<br />
Cleopatra likewise gave one to Antony. Louis XIII.<br />
brought chrysolite into fashion at his court.<br />
Among the engravings in chrysolite is one of the Em-
IOLITE. 29Y<br />
peress Sabine, which is in the cabinet of Crispi, at Ferrara.<br />
Among the most extraordinary engravings in chrysolite,<br />
is one representing Ptolomeus-Oulet, king of Egypt, and<br />
the Nuptials of Cupid.<br />
IOLITE.<br />
This mineral has for a long time been brought from<br />
Spain, but has lately been made known and brought into<br />
notice by Cordier, afte'r whom it received the name cor-<br />
dierite / it is called likewise steinheilite^ and has several<br />
other names, which I will mention, in order that the reader<br />
may not be confused when the same mineral is presented<br />
as a gem, under different names; the most appropriate<br />
name is dichroite, from its property of displaying two<br />
colors when held in different directions ; it is also known<br />
aspeliom and prismatic quartz.<br />
It occurs in regular six and twelve sided prisms ; also, in<br />
crystalline grains, massive, and in pebbles ; its fracture is<br />
conchoidal and uneven ; it is transparent,<br />
exhibiting an indigo-blue color when held<br />
in the direction of its axis, or viewed by<br />
transmitted light, and appearing brown-<br />
ish-yellow when held at right angles ; it<br />
possesses some double-refracting power.<br />
Sometimes a ray of light, resembling that<br />
of the star-sapphire, may be perceived in<br />
iolite, particularly when cut; it has a<br />
vitreous lustre ; its colors are violet-blue<br />
and indigo-blue, sometimes with a tinge<br />
Fig. 11,<br />
of black and bluish-gray. It scratches glass, and is attacked<br />
by topaz ; its streak-powder is white ; hardness, 6'5 ;<br />
it<br />
it becomes<br />
ha's a specific gravity of 2*88. By rubbing,<br />
electric, and assumes polarity by heating ; it is difficult to
298 A POPULAR TREATISE ON GEMS.<br />
fuse on the edges, and becomes then a grayish-green<br />
enamel : borax fuses it into a diaphanous glass ; acids have<br />
no effect upon it ; it consists of magnesia, alumina, and<br />
silica, with some oxide of iron and water.<br />
It is often found under the names of lynx and water<br />
sapphire, the first of a pale<br />
and the latter of a darkish blue<br />
color. It is found in primitive rocks ; also, in blue day,<br />
in copper pyrites, in quartz or felspar, and in small de-<br />
tached masses ; the localities are at Baldenmays in Bavaria,<br />
occasionally in perfect crystallizations, but usually massive ;<br />
'<br />
it is associated with magnetic pyrites. The variety from<br />
this locality has been called peliom, from its peculiar smoky-<br />
blue color, from rrehiog. It occurs in quartz, at Ujordlero-<br />
soak, in Greenland ; in granite, at Cape de Gata, in Spain ;<br />
at Arehdal, in Norway ; at Orrijervi, in Finland ; at Tuna-<br />
berg, in Sweden, &c. Ceylon affords a transparent variety<br />
in small rolled masses of an intense blue color. At Had-<br />
dam, Connecticut, it is associated with garnet and anthoph-<br />
yllite in gneiss. It is occasionally employed as a gem,<br />
and when cut exhibits its dichroism, or different colors in<br />
different directions. The name iolite is derived from tov,<br />
a violet, and /U0o, stone, in allusion to its color. From its<br />
property of exhibiting different colors according to the<br />
direction in which it was viewed, it has also been named<br />
dichroite, from 61$, double, and %poa, color.<br />
The hydrous* iolite, from Sweden, of grayish-brown or<br />
dark olive-green . color, is a very soft mineral ; hardness,<br />
3'75 ; occurs in red granite, accompanied by a light bluish-<br />
gray iolite.<br />
If the stone is perfectly pure, it is used for rings and<br />
breastpins; is cut on a copper wheel with emery, and<br />
polished on a tin plate with rotten-stone, and receives the<br />
form of a cabochon, in order to let it display its proper<br />
colors, and in a cube form. Its price is not very high ; the
PRECIOUS OPAL. 299<br />
jewellers value it as an inferior quality of the sapphire,<br />
without paying any regard to its phenomena of light.<br />
Good-sized specimens are sold at about eight to ten dollars<br />
each ; at Paris, a good iolite, ten lines long and eight and<br />
a half broad, was sold for one hundred and sixty francs.<br />
When, a couple of years ago, the iolite was discovered by<br />
Professor Mather, at Haddam, Connecticut, it promised to<br />
be a valuable acquisition to American gems ; but the<br />
suppfy was very scant, and its original locality appears to<br />
be exhausted. Professor Torrey possesses a fine seal, in<br />
the form of a cube, from that locality, which displays its<br />
properties to the greatest perfection.<br />
A blue quartz is occasionally sold for iolite, but it may<br />
easily be distinguished by its colors and hardness. Sapphire<br />
is considerably harder than the iolite.<br />
OPAL.<br />
The precious variety of this mineral was known to the<br />
ancients, and received its name on account of the "play of<br />
colors which it has. The opal has a great many varieties,<br />
which are all considered more or less gems, and find their<br />
will therefore be treated<br />
application in jewelry ; they<br />
separately. But, as general characters, it may now be mentioned<br />
that opal scratches glass but slightly, while it is<br />
marked by rock-crystal ; it has a specific gravity of 2'OG.to<br />
2'11 ; it is infusible before the blowpipe, but decrepitates<br />
and falls into splinters ; it also dissolves with borax. Opal<br />
consists of silica with water, some oxide of iron, and some-<br />
times alumina.<br />
'<br />
PRECIOUS OPAL.<br />
This gem derives its name from the Greek word sig<br />
nifying the eye, for the ancients believed that this stone<br />
: *
300 A POPULAR TllEATISE ON GEMS.<br />
had the. power of strengthening the eye. It was highly<br />
esteemed by them, as we learn from l^liny, who thought<br />
that the play of color originates from the beautiful colors<br />
of the carbuncle, amethyst, and emerald.<br />
The phenomenon of the play of colors in the precious<br />
opal has not yet been satisfactorily explained. Hatiy attrib-<br />
utes it to the fissures of the interior being filled with films<br />
of air, agreeably with the law of Newton's colored rings,<br />
when two pieces of glass are pressed together. Mohs'con-<br />
tradicts this theory upon reasonable grounds, which are, that<br />
the phenomenon would present merely a kind; of irides-<br />
cence. Brewster concludes that it is owing to fissures and<br />
cracks in the interior of the mass, not accidental but of<br />
a uniform shape, and which reflect the tints of Kewton's<br />
scale ; but it is, in my opinion, sufficiently plausible, that<br />
the unequal division of smaller and larger cavities, which<br />
are filled with water, produces the prismatic colors, and for<br />
the simple reason that" the opal which grows, after a while,<br />
dull and opaque, may be restored to its former beauty if<br />
put<br />
for ti short time in water or oil.<br />
Although the precious opal was never found in the East,<br />
yet it bears the name of Oriental opal among jewellers:<br />
for in former times opals were carried by the Grecian and<br />
Turkish merchants from Hungary, their native locality,<br />
to the Indies, and brought back by the way of Holland<br />
to Europe, as Oriental opals. The precious opal is found,<br />
in small irregular gangues, nests of the trachytic por-<br />
phyry formation and its conglomerates, in Hungary, particularly<br />
in the neighborhood of the village of Czerwin-<br />
ccza ; also, in the Faroe Islands, Saxony,<br />
and South America.<br />
The Hungarian opal is found of various qualities, and is<br />
obtained from mines which have been wrought<br />
for several<br />
centuries ; and, according -to the archives of that part of<br />
the country, there were, in the year 1400, more than three
PRECIOUS OPAL. 301<br />
hundred workmen engaged at the mines near tlt above<br />
village ; whereas there are but thirty at present engaged<br />
there,<br />
mens.<br />
on account of the scarcity of large suitable speci<br />
The precious opal is principally used for rings, ear-rings,<br />
the smaller specimens for mount-<br />
necklaces, and diadems ;<br />
ing snuff-boxes, rings, chains, &c. It is ground on a leaden<br />
wheel with emery, and is polished with rotten-stone and<br />
water on a wooden wheel ; and, in order to increase its<br />
lustre, it is lastly rubbed with putty, by means of buckskin,<br />
or a woollen rag and red chalk. Its form is generally that<br />
of a semicircle, lens, or oval; sometimes of a table, and<br />
then also with some facets ;<br />
but great care has to be taken<br />
that the edges, on account of the softness of the stone, do<br />
not wear off. It is also apt to spring in a temperature sud-<br />
denly changing. When mounted,<br />
it receives a colored<br />
foil, or a variegated silk stuff, or a peacock-feather<br />
on the<br />
back, but it looks best in a black casing.<br />
Cracks and fissures may be removed by leaving the pre-<br />
cious opal for some time in oil. Very frequently the pre-<br />
cious opal is distributed in small particles in the matrix,<br />
called mother of opal, which is cut by the jewellers as<br />
boxes, and other ornaments 4 and very often, too, this<br />
matrix is plunged into oil, and exposed to a moderate heat,<br />
whereby the base grows b.lacker, and the true precious<br />
opal retains its ray of colors. In order to preserve the<br />
surface of the precious opal against wear and tear, it is<br />
covered with a thin plate of quartz crystal. The precious<br />
opal still stands in very high estimation, and is considered<br />
one of the most valuable gems. The size and the beauty<br />
those playing<br />
displayed by its colors determine its value ;<br />
in the red and green colors bear the highest price. Its<br />
value has latterly increased on account of the scarcity of<br />
the larger specimens. Formerly, a solitary large precious
302 A POPULAR TREATISE ON GEMS.<br />
opal, playing in the red color, was sold for two to three<br />
hundred ducats; and one playing in both red and green<br />
colors, about five lines long, was sold at Paris for two<br />
thousand four hundred francs; and lately a single opal, of<br />
fine colors, and the size of a dollar, was sold near the<br />
locality for three hundred thousand florins ; in this country<br />
precious opals are sold by the importers at the rate of<br />
four to ten dollars per carat, and single specimens, suitable<br />
for pins or rings, from two to twenty dollars. The mother<br />
of opal is, however, much cheaper ; one of five lines size is<br />
sold for three to five dollars.<br />
All experiments for imitating the precious opal have<br />
hitherto proved fruitless ; they were made either by preparing<br />
an enamel and adding several metallic oxides, or by<br />
affixing to the back of a clear or common opal or enamel, a<br />
polished thin plate of the mother of pearl, which may sometimes<br />
deceive the ignorant.<br />
The precious opal, when large and exhibiting its peculiar<br />
play of colors in perfection, is a gem of considerable value;<br />
it was used as an ornament among the Greeks and Romans,<br />
and was called opalus ; also paederos (Ttaidepd)?) , in allusion<br />
to its color and lustre as expressed in<br />
"<br />
Ipeprov repeva xpoa naidbs, having<br />
the :<br />
Orphic poem<br />
the delicate complexion<br />
of a lovely youth." The most magnificent Hungarian<br />
opal in the London Exhibition, called "the mountain<br />
of light" a very appropriate name weighed 526 carats,<br />
and was estimated at 4000 pounds sterling.<br />
From Honduras, at Gracias a Dios, large quantities of<br />
opals have been imported into this city for the last ten years,<br />
at first by the late Mr. De la Raye, and latterly by Mr.<br />
Aaron C. Burr ;<br />
and many large and beautifully cut speci-<br />
mens are in the possession of Mr. B. Palmer, of this city;<br />
they are by no means inferior to the Hungarian opal. A<br />
very large opal, cut and polished by himself, which he
PRECIOUS OPAL. 303<br />
values at four thousand dollars, is one and three quarters<br />
inches long by one and a quarter inches wide ; another,<br />
one and a quarter inches long by one inch wide, he prizes<br />
at. seven hundred and fifty dollars; and a third, one and<br />
one eighth inches long by one inch wide, he values at four<br />
hundred and fifty dollars.<br />
The ancients held the opal in great estimation, and the<br />
anecdote of the Roman senator, Nonius, is well known<br />
that he preferred exile to parting with a magnificent opal<br />
which Marc Antony coveted.<br />
In the French crown-jewels are two very large and<br />
beautiful opals. One is set in the centre of the Order of<br />
the Golden Fleece, and the other forms the clasp of the<br />
imperial cloak. They were purchased for 75,000 francs.<br />
The Empress Josephine possessed the unique oppl which<br />
was called " The Great Fire of Troy," on account of the<br />
great fire sparkles.<br />
The Vienna Cabinet possesses a very large opal, but<br />
unfortunately it is cracked. Count Walewski, who is a<br />
great amateur of gems, possesses a very beautiful opal,<br />
which is oval, the size of a franc-piece, and is said to be<br />
extraordinarily brilliant,<br />
The Imperial Mineralogical Cabinet at Vienna, contains<br />
the most celebrated specimens of precious opal ; one, par-<br />
ticularly, may<br />
be mentioned here: it is four and three<br />
quarter inches long, two and a half inches thick, and weighs<br />
seventeen ounces. It was discovered about' 1770, at the<br />
above locality, and transported to Vienna. It displays the<br />
most magnificent colors ;<br />
is perfectly pure, and not accom-<br />
panied by any. matrix. Half a million of florins were<br />
offered for it by a jeweller of Amsterdam, and refused on<br />
account of its uniqueness ; and the Viennese have not yet<br />
dared to put even any approximate value upon it.
304 A POPULAR TREATISE ON GEMS.<br />
FIRE OPAL.<br />
This mineral was first brought into notice by Baron<br />
Humboldt, who found it in Mexico.<br />
It occurs massive ; has a conchoidal fracture ; is trans-<br />
parent ; of strong vitreous lustre ; color, hyacinth-red, run-<br />
ning into honey, wine-yellow, showing carmine-red and<br />
sometimes containing dendritic draw-<br />
greenish reflections ;<br />
ings. Its specific gravity is 2 '02 ; loses one and a half per<br />
cent, by calcination, and leaves pale flesh-red fragments. It<br />
is found in the trachytic porphyry, in Mexico, and in the<br />
amygdaloid of the Faroe Islands.<br />
As the fire opal is very little known, it has not yet<br />
been employed in jewelry, but bids fair to find applications.<br />
It is ground on a leaden wheel with emery, and<br />
polished with rotten-stone on a wooden wheel. The forms<br />
of cabochon, table, or pavilion, might suit very well as ring-<br />
stones.<br />
The cabinet of the university of Bonn possesses a very<br />
large and fine fire opal, of the size of the fist. The largest<br />
specimen I have seen is in the royal mineral ogical cabinet<br />
at Berlin, which was deposited by Baron Humboldt on<br />
his return from South America, and which, if I recollect it<br />
well enough from the year 1827, must be at least six inches<br />
long and four inches thick. This is the largest specimen<br />
he ever found. A collection of six shades of fire opal, with<br />
six more varieties of the other opals, was presented to me<br />
in the year 1828, when in Berlin, by the Counsellor Berge-<br />
man, who received at that time a considerable quantity of<br />
polished specimens from the Faroe Islands, but all of small<br />
size. A splendid collection of fire opals was brought from<br />
Guatemala some years ago to this country. It is also called<br />
girasol, from its bright hyacinth-red tints.
HYDROPHANE. V , 305<br />
CO3CMOX OPAL.<br />
This mineral occurs massive and in rolled pieo^; also as<br />
stalactites; has a cOnchoidal fracture;<br />
is transient and<br />
semi-transparent ; has a strong vitreous and resinous lustre ;<br />
its colors are. milky, yellow, reddish, greenish-white, honey-<br />
yellow, wine-yellow, flesh, brick-red, and olive-green ;<br />
some-<br />
times dendritic (moss opal). Its specific gravity is 1 '9 to 2*1.<br />
The wax or pitch opal is subordinate to this variety.<br />
It is found in the same rocks as the precious opal, in Hun-<br />
gary ; in the hematite rocks of Saxony ; in the serpentine<br />
of Silesia; in cavities of trap and the amygdaloid rocks of<br />
Iceland ; 'Faroe Islands ; and in the United States (Penn-<br />
sylvania and Connecticut).<br />
It is used for rings, pins, and cane-heads ; but is, on the<br />
whole, not a favorite among jewellers,
306 A POPULAR TREATISE ON GEMS.<br />
It has, when dry, a white, yellowish, or reddish color, and<br />
a specific gravity of 1*95 to 2'01 and ; according to Hatly,<br />
a<br />
hydroplane, having been immersed for four minutes in<br />
water, gaiRd thirty-four centigrammes:<br />
The hydrophane is found in the porphyry of Hungary,<br />
France, Iceland, and the Faroe Islands. Large pieces of<br />
good and fine specimens of hydrophane are wrought and<br />
used in the same manner as the precious opal.<br />
It is said that the hydrophane becomes much quicker<br />
transparent in warm than in cold water ; the quickest in<br />
spirits of wine ; after which, it loses this property the<br />
sooner ; but when boiled in oil, it retains it, to a certain<br />
extent, for years.<br />
If the hydrophane is well dried and soaked in melted<br />
white wax, or spermaceti, it assumes the property, when<br />
warmed, of becoming translucent, and of displaying brown-<br />
ish-yellow or gray colors ; it is then called pyrophane.<br />
The hydrophane was formerly colored violet or red, by<br />
means of a decoction- of logwood and alum.<br />
The price of hydrophane is very high, on account.of its<br />
great scarcity, and because it is very seldom found in large<br />
lumps.<br />
"SEMI-OPAL.<br />
This variety of opal was formerly considered to be a<br />
pitch-stone, and if it assumes the fonn of petrified wood, it<br />
is called wood opal. It has a conchoidal and even fracture ;<br />
it is translucent and opaque; of a resinous and vitreous<br />
lustre ;<br />
its colors are yellowish, grayish, and brownish, the<br />
colors running mostly dnto one another ; sometimes the<br />
colors divide themselves ribbon-like. The wood opal is<br />
mdstly brownish, and displays, more or less, a ligneous<br />
aspect, with the form of branches.<br />
The semi-opal is found in gangues, in the trachytic
CACHELONG. 307<br />
porphyry in Hungary, in the serpentine in Silesia, in the*<br />
amygdaloid in Iceland and the Faroe Islands ;<br />
likewise in<br />
Moravia, Saxony, France, Greenland, and in the United<br />
States (Maryland and Pennsylvania).<br />
The semi-opal, on account of its taking a high polish, is<br />
used for many purposes in jewelry. There is an estab-<br />
lishment for manufacturing snuff-boxes from wood opal, in<br />
Vienna, and lately the varieties of wood opal, with layers of<br />
chalcedony, or semi-opal, have found a useful application for<br />
the cutting of cameos. The semi-opal is ground and polished<br />
like the precious opal, but with more difficulty, on account<br />
of its being more brittle. The form which it easily receives<br />
is in cabochon, but without facets. The price of the semi<br />
or wood opal is low.<br />
CACHELONG.<br />
According to Blumenbach, the name of this mineral is pf<br />
Mongolian derivation, meaning " a pretty stone ;" and ac-<br />
cording to Phillipps it receives its name from the river Cach,<br />
in Bucharia, on whose shores it occurs frequently in loose<br />
conglomerates. This mineral has been arranged under the<br />
head of chalcedony, but properly belongs to opal.<br />
It occurs massive, as a covering of other minerals, rarely<br />
reniform, often traversed with fissures in different directions.<br />
It has a conchoidal fracture ; is opaque, and of a pearly<br />
lustre ; milky-white, turning sometimes to a yellow or red<br />
color, and exhibits dendritic figures of manganese or green<br />
earth. ; It scratches white glass ; has a specific gravity of<br />
2'2 ; it decrepitates when first brought before the blow-<br />
pipe, but yet undergoes no change ;<br />
slowly, at a white heat.<br />
clissolves with borax,<br />
It is found in the same manner as chalcedony, some-<br />
times incrusting or penetrating it, in the amygdaloid of<br />
Iceland, Greenland, the Faroe Islands, the hematite of
308 A POPULAR TREATISE OX GEMS.<br />
Carinthia, the United States (Massachusetts),<br />
and Neva<br />
Scotia ; in Bucharia, in the sand of the river Cach, it is<br />
found loose.<br />
Caclielong being generally constituted of layers of different<br />
degrees of hardness, the sculptors of cameos profit<br />
thereby, for the purpose of producing better bas-reliefs.<br />
In the Imperial Library, at Paris, is a very fine cameo,<br />
representing Valentine III.<br />
Cachelong is much used in jewelry, for rings, seals, &c.<br />
The Calmucks of Bucharia manufacture of it tools and<br />
other domestic articles. It is cut on a copper wheel with<br />
emery, in cabochon, and receives the polish on lead plates<br />
by means of rotten-stone and putty. The price of the<br />
cachelong is pretty considerable, on account of its beauty<br />
and scarcity, as the specimens most frequently found in<br />
the above localities are seldom in layers of more than one<br />
quarter of a line, alternating with chalcedony.<br />
JASPER OPAL.<br />
This mineral stands between jasper and opal; and, al-<br />
though considered by Werner as belonging to the first,<br />
ought, nevertheless, more properly to be arranged with the<br />
opal, on account of its containing water in its. composition.<br />
The jasper opal occurs massive, in specks, stalactiform, and<br />
in geodic masses; it has a conch oidal fracture; is translu-<br />
cent on the edges, or opaque ;<br />
is of a strong resinous lustre;<br />
its colors are gray, yellow, red, and brown. Its specific<br />
gravity is 2'0 to 2*1. It consists of silica, water, and oxide<br />
of iron, amounting to forty-seven per cent. It is found in<br />
the trachytic breccias of Hungary; also, in Saxony -and<br />
Siberia. The best light and pure specimens are used for<br />
dagger and sword handles in Turkey. The price of jasper<br />
opal is low.
OBSIDIAN. 309<br />
OBSIDIAN.<br />
This mineral was familiarly known to the ancients, and<br />
its name is said to be derived from a Rpman, who first<br />
brought it to Rome from Ethiopia. Pliny states that the<br />
Romans manufactured mirrors and gems from it; the<br />
Mexicans and Peruvians manufactured their knives, razors,<br />
and sword-blades from obsidian, which appears to have<br />
served as a complete substitute for other materials with<br />
those nations, who were yet unacquainted with the use of<br />
iron for weapons and utensils of various kinds. Baron<br />
Humboldt says that Cortez mentioned, in his letter to the<br />
Emperor Charles V., having seen razors of obsidian at<br />
Tenochittan ; and the above naturalist likewise discovered,<br />
on the Sierra de las Nabajaz, in New Spain, the old shaft<br />
that was used for raising the rough obsidian, with relics<br />
of the tools and half-finished utensils.<br />
The inhabitants of Quito manufactured magnificent mir-<br />
rors from obsidian, and those. of the Azores and Ascension<br />
islands, and Guiana, used splinters of obsidian as points for<br />
their lances, razors, &c.<br />
Specimens of arrows and other articles, such as octangular<br />
wedges, were presented a few years ago to the New<br />
York Lyceum of Natural History, being relics from the<br />
ruins of Palenque. In the collection of Columbia College<br />
are some razors, or sacrificial knives, the gift of the Hon.<br />
J. R. Poinsett.<br />
Obsidian occurs massive, in roundish or obtuse lumps,<br />
balls, and grains ; has a conchoidal fracture ; is semi-trans-<br />
parent and translucent on the edges ;<br />
ous, and sometimes even metallic lustre;<br />
it has a strong vitre-<br />
its colors are<br />
either pure black, grayish, brownish, greenish-black, yellow,<br />
blue, or white, but seldom red; it sometimes displays a<br />
peculiar greenish-yellow shine, when it is called the irides-
310 A POPULAR TKEATISE ON GEMS.<br />
cent obsidian ; there is rarely more than one color in the<br />
same specimen with stripes and specks.<br />
Obsidian scratches<br />
white glass indifferently, but is scratched by topaz; its.<br />
streak-powder is white ; it has 'a specific gravity<br />
of 2*34 to<br />
2'39. Obsidian is sometimes magnetic, so that small pieces<br />
show their magnetic poles. Before the blowpipe, the black<br />
and even at a white<br />
variety is fusible with much difficulty ;<br />
heat it does not melt into a solid glass ; but the gray and<br />
brown variety (marekanite) swells readily into a spongy<br />
mass.<br />
Obsidian consists of silex, alumina, with a little potassa,<br />
soda, and oxide of iron.<br />
The names, Iceland agate, lava, black-glass lava, volcanic<br />
lava, are all synonymous, and the mineral called bottlestone,<br />
in round grains of the size of a pea, is nothing but<br />
a green obsidian.<br />
Obsidian, sometimes, forms the cement of .whole mountain<br />
chains, often forms deposits in the trachyte and the<br />
streams at the foot of some volcano ; also, among the vol-<br />
canic ejections, and occurs in loose lumps in the sand of<br />
rivers, and at the foot of mountains. It is found in Iceland,<br />
Teneriffe, the Lipari Islands, Peru, Mexico, Sicily, Hungary,<br />
Asiatic Russia, the Ascension Islands, and on all the vol-<br />
canoes of former and present times.<br />
In the New York Lyceum of Natural History are several<br />
interesting specimens, presented by Don Correa, of Ta-<br />
basco, from the ruins of the city of Palenque ;<br />
such as con-<br />
cave or triangular wedges, and other masses of obsidian,<br />
from various localities.<br />
It is employed for several useful and ornamental pur-<br />
poses ;<br />
such as the making of ear-rings, necklaces, brooches,<br />
snuiF-boxes, knife handles, &c. -It is particularly worn as<br />
mourning jewelry; it requires, however, much care in<br />
working, being extremely brittle. It is ground<br />
on lead
AXINTTE. 311<br />
wheels with emery, and polished -with rotten-stone. It is<br />
kept in favor by the jewellers, on account of its high polish ;<br />
but its value is very indifferent, excepting that of the iri-<br />
descent obsMian, which commands a high price, and is<br />
sometimes seen cut in cabochon, and set in rings.<br />
There is no doubt but that obsidian is of volcanic origin^<br />
being mostly found in the neighborhood of volcanoes, and<br />
that it is a glass, produced by volcanic fire, as it is a<br />
combination of silex and alkaline substances. The Neptunian<br />
theorists have endeavored to prove that it is occasion-<br />
ally found with the remains of decomposed granite, gneiss,<br />
and porphyry, with which it even alternates in layers.<br />
AXINTTE.<br />
The name of this mineral is derived from a Greek word,<br />
signifying an axe, and was applied to it oh account of the<br />
resemblance of its crystals to that implement ; it is also<br />
called by some English mineralogists, thumer-stone, from<br />
its first locality.<br />
-<br />
; :<br />
Axinite occurs in a variety of crystalline forms, which<br />
are reducible to the rhombic, viz : an oblique rhomb, or<br />
four-sided prism, so compressed that the edges appear<br />
sharp, like the edge of an axe ; likewise} massive and in<br />
specks ; its fracture is uneven ; it is translucent on the<br />
edges, or sometimes transparent; hag simple refraction<br />
of light ; its lustre is vitreous, also, resinous ; its colors arc<br />
violet-blue, brown, gray, and yellow;<br />
it scratches white<br />
glass, but is scratched by topaz ; has a white streak-powder ;<br />
its specific gravity is 3*27 ; it becomes electric by rubbing<br />
or heating; before the blowpipe it fuses into a grayishbrown<br />
glass ; acids have no effect upon it ; it consists of<br />
lime, alumina, and silex, with oxide of iron and manganese.<br />
It occurs in gangues and layers of various formations,
31T2 A POPULAR TREATISE ON GEMS.<br />
principally the primitive ; and is found in Dauphine, the<br />
Pyrenees, Gothard, Saxony (Thum), Norway, &c.<br />
This mineral takes a very high polish, particularly those<br />
specimens from Dauphine^ but has hitherto, on account of<br />
its scarcity, not found much application in jewelry, but will<br />
Hereafter be a great acquisition, as it may be used for rings,<br />
pins, and other small ornaments<br />
FELSPAR.<br />
The varieties of this mineral are mostly crystallized, and<br />
in very numerous forms ; but they are all distinguished by<br />
two great characters, which are, the foliated structure and<br />
peculiar lustre; the principal form is an oblique prism<br />
with unequal sides. Felspar scratches glass and is scratched<br />
by rock crystal ; its streak-powder is white ; it has a<br />
specific gravity of 2*5 to 2*6; before the blowpipe it fuses<br />
with difficulty ; on charcoal it becomes vitreous and white ;<br />
fuses with difficulty on the edges to a translucent white<br />
enamel ; acids have no effect upon it ; it consists of potash,<br />
alumina, and silex.<br />
ADULARIA.<br />
This mineral occurs in crystals (oblique prisms and rhom-<br />
boidal faces), crystalline fragments, and solid masses; its<br />
fracture is uneven; it is translucent on the edges; has<br />
double refraction of light ; the lustre is vitreous and pearly,<br />
more especially when cut and polished ; it throws out green-<br />
ish and bluish-white chatoyant reflections from the interior ;<br />
it cleaves in two directions ; the crystals often present the<br />
hemitrope form, which in polished specimens becomes obvious<br />
from the different directions of the laminae; its' colors<br />
are limpid-white, greenish, grayish, and bluish, frequently
ADULARIA. 313<br />
with a peculiar pearly shine, and sometimes it is iridescent.<br />
and softer than quartz.<br />
Specific gravity, 2 '5 ;<br />
In commerce, adularia goes under various names, such<br />
as ^noon-stone, sun-stone, girasol, fish-eye, and Ceylon or<br />
water opal. In the moon-stone the color is white, with<br />
small bluish or greenish shades, but the base is semi-trans-<br />
parent and milky ; whereas the sun-stone shows a yellow<br />
and reddish play of colors. Adularia is found in gangues<br />
and" cavities of granite, gneiss, and limestone, and in<br />
pebbles from Ceylon, Greenland, Bavaria, St. Gothard,<br />
Tyrol, Dauphine, and in the United States, particularly<br />
at Ticonderoga, near Lake Champlain, New York, Maryland,<br />
Pennsylvania, Connecticut, and Massachusetts. The<br />
adularia from St. Gothard is found in very large masses : I<br />
saw, in 1827, in the cabinet at Zurich, in Switzerland,<br />
groups of crystallized adularia, measuring two feet in<br />
length and one foot in thickness, the splendor of which<br />
dazzled my eyes.<br />
Adularia, displaying a good color, and strong pearly<br />
reflections, is now much used in jewelry, for rings, pins,<br />
and other smaller ornaments. Generally specimens which<br />
possess these qualities are cut out of large lumps, then<br />
ground on a lead wheel, in cabochon form, and polished<br />
with rotten-stone ; they are, hi general, mounted in a black<br />
case, whence it best shows its reflections. The moon-stone<br />
commands a good price ; exquisitely fine specimens, of the<br />
size of a bean, are worth from five to ten dollars, and some<br />
of them were sold at Paris, of six lines diameter, for seven<br />
hundred and five francs, and four lines for two hundred and<br />
three francs.<br />
The largest moon-stone, in a brooch, three fourths of an<br />
inch in length, I have seen, is in the possession of Francis<br />
Alger, Esq., of Boston ; and rough specimens, with most<br />
splendid reflections, I have admired in the collection of the<br />
14
314 A POPULAR TEEATISE ON GEMS.<br />
late Dr. M. Gay, of the same city. Both these gentlemen<br />
are fortunate in possessing uniques in this country, which<br />
are of no ordinary scientific and commercial value.<br />
Among the varieties of felspar may be named ice-sf>ar,<br />
which is found in volcanic rocks, occurs crystallized in the<br />
Vesuvian lavas, and is of a white color.<br />
Murchisonite is a yellowish-gray variety of felspar, from<br />
Dawlish and Arran.<br />
Leclite^ or the hettefliata of the Swedes, has a peculiar<br />
waxy lustre and a deep flesh-red color, and is found at<br />
Gryphyttan, in Sweden,<br />
Conazeranite is a grayish-black or blackish-blue variety,<br />
from the steep defiles of Salleix, in the Pyrenees ; it occurs<br />
imbedded in limestone.<br />
Variolite is a dark-green variety of felspar, containing<br />
lighter globular particles ; originally found in Drac river,<br />
in France, but of late also in Piedmont, Switzerland, and<br />
Scotland ; in the Alps large blocks of several thousand<br />
pounds are found. This stone, when polished, takes a high<br />
gloss, equal to the most precious gems. Its name is derived<br />
from the peculiar spots flashing around the stone.<br />
The name adularia is derived from Adula, the ancient<br />
name of St. Gothard, where the prettiest specimens were<br />
first discovered.<br />
A very curious variety has been found in Siberia, of a<br />
yellowish color, but with innumerable gold spots disseminated<br />
throughout' the whole surface of the mineral;<br />
these reflections of light appear to be owing to very small<br />
fissures or cracks, or to a confusion of its lamellar system.<br />
The prettiest specimens, which are invariably cut in cabo-<br />
chon, look much like a reflection of a star, diverging from<br />
the centre ; they are very rare, however. This variety of<br />
moon-stone has often been confounded with the Oriental<br />
avanturine, but on examination may at once be detected.
COMMON FELSPJte. 315<br />
The Ceylon variety ought only to be called Oriental moon-<br />
stone, from the peculiarity that it is more uniform, not<br />
striated like that from St. Gothard, and having also a<br />
brighter lustre; its chatoyant qualities are therefore more<br />
prominent.<br />
Sun-stone contains minute scales of mica, and reflects a<br />
pinchbeck-brown tint.<br />
COMMON FELSPAE.<br />
This felspar occurs in crystals, massive, and disseminated ;<br />
its fracture is uneven and splintery ; is translucent ; has a<br />
pearly and vitreous lustre ; its colors are white, gray, red,<br />
yellow, and green, in their various shades, sometimes with<br />
a variegated bluish, greenish, or reddish play of colors ; its<br />
texture is compact, or minutely foliated.<br />
The amazon-stone, or green felspar, is from Siberia ; like-<br />
wise splendid grass-green felspar has been found in the United<br />
States, at Southbridge and Hingham, Massachusetts, and<br />
Cow Bay, New York; of apple-green color, at Topsham,<br />
and near Baltimore, Maryland. Also, the American glassy<br />
or vitreous felspar, found in Delaware, which ought prop-<br />
with this<br />
erly to be quoted as a distinct species, is arranged<br />
variety.<br />
Felspar is widely diffused all over the globe,<br />
and with a<br />
few exceptions is more common than any other mineral ;<br />
forms a constituent part of most primitive rocks, such as<br />
gneiss, granite, &c. ; is the principal ingredient of the<br />
sienites, porphyry, and, in fact, with a small percentage of<br />
other minerals, forms whole mountain ranges and chains in<br />
various parts of the globe : such we see in Siberia, the north<br />
and west of Scotland, &c., all of which are surrounded by<br />
felspar. Immense beds exist in the United States : around<br />
Wilmington, in the State of Delaware, is an inexhaustible<br />
deposit of exquisite and perfectly pure felspar; and ID<br />
it
316 A POPU1*E TREATISE ON GEMS.<br />
Connecticut and on the North River we see beds of the<br />
foliated felspar extending for miles. Sweden, Norway, and<br />
Greenland are likewise great depositories of the common<br />
felspar.<br />
The amazon-stone is used in jewelry for rings, pins,<br />
seals, snuff-boxes, &c. It is principally cut at Ekaterinen-<br />
burg, Siberia, where it is ground on a leaden wheel with<br />
emery, and polished with* rotten-stone on a wooden wheel;<br />
its form is that of cabochon, and sometimes that of the<br />
mixed pavilion-cut, when the table is to be cut pretty large,<br />
and arched, in order to display more distinctly its peculiar<br />
colors.<br />
Common felspar is of no great value, and . only<br />
the amazon-stone<br />
is used in jewelry, which commands a good<br />
price. Cut specimens, suitable for ear-rings or brooches,<br />
are worth from three to five dollars.<br />
A very fine specimen of the amazon-stone, in its rough<br />
state, may be seen in the New York Lyceum of Natural<br />
History. The imperial cabinet of St; Petersburg possesses<br />
two vases of this stone, which are nine inches high and five<br />
and one half inches in diameter. Although our vitreous<br />
felspar has not yet been brought into use for the purposes<br />
of jewelry and other ornaments, yet it bids fair to con-<br />
tribute, at one day, much to the national wealth of this<br />
country, for it is the best material for porcelain, china, and<br />
earthen-ware. Already have many cargoes of this beautiful<br />
mineral been shipped to France and England (six hundred<br />
tons of the Connecticut, Middletown, felspar were, accord-<br />
ing to Professor Shephard, last year shipped to Liverpool,<br />
and one hundred tons to the Jersey porcelain manufactory),<br />
where the manufacturer appears to appreciate better the<br />
purity of ingredients for the purposes just mentioned. Instead<br />
of<br />
receiving, as hitherto, the manufactured goods<br />
from abroad, made of our own raw material, it is earnestly
LABRADOR. 317<br />
to be hoped that w will shortly acquire skill, and exert<br />
sufficient industry to compete with loreign manufacturers<br />
in the art of making porcelain, with the superior material<br />
which nature has so abundantly lavished on this continent.<br />
I possess a splendid slab of the vitreous felspar, of one<br />
square foot, free from any admixture, and imposing in<br />
appearance.<br />
LABRADOR.<br />
This mineral was heretofore considered as a variety of<br />
felspar; but it has latterly been separated from it, and<br />
ought, therefore, no more to be called labrador felspar, the<br />
name by which it is known in all mineralogical works.<br />
Labrador was first discovered by the Moravian mission-<br />
aries on the island of St. Paul, on the coast of Labrador;<br />
and, according to others, by Bishop Launitz, in 1775,<br />
when it was first brought to Europe. Labrador occurs in<br />
crystalline masses, massive, and in boulders; it is of an<br />
uneven and conchoidal fracture ; its lustre is vitreous, and<br />
in one direction pearly; it is translucent; its colors are<br />
gray, with its various shades, such as blackish or whitish-<br />
gray, with spots of an opalescent or iridescent vivid play of<br />
colors, consisting of blue, red, green, brown, yellow, or<br />
orange, according to the direction in which light is falling<br />
upon the specimen ; sometimes several of these colors arje<br />
perceptible at the same instant, but more commonly they<br />
appear in succession as the mineral is turned towards the<br />
light. These colors are said to originate in fissures which<br />
intersect the texture of the mineral, as they are only perceptible<br />
from that side where they fall together with the<br />
foliated structure, and not like the opal, whose mass is sup-<br />
plied with fissures running in all directions.<br />
Labrador scratches white glass, is? scratched by rock-<br />
crystal, and is somewhat less hard than felspar ; its specific
318 A POPULAB TREATISE ON GEMS.<br />
gravity is 2'7l to 2'75 ; before the blowpipe<br />
difficulty, and is said to lose its play of colors ;<br />
it fuses with<br />
it consists<br />
of silex, alumina, lime, soda, with some oxide of iron and<br />
water. Labrador is found as a rock and boulder, in St.<br />
Petersburg, Norway, Bohemia, Saxony, Sweden, St. Paul's<br />
Island on the coast of Labrador, and in the United States,<br />
in Essex county (New Jersey), at the mouth of the North<br />
River, and near Lake Champlain, New York, where,<br />
according to the description given me by Archibald Mc-<br />
Intyre, Esq., its splendid colors are seen on both sides of<br />
the water, but a few yards apart, and the effect of the rays<br />
of the morning sun falling upon the rock and water at the<br />
same time, is said to equal that of the prismatic spectrum<br />
thrown into a dark room.<br />
Labrador is used for rings, pins, buttons, snuff-boxes,<br />
letter-holders, cane-heads, and other ornaments, such as<br />
vases and larger articles; but care has to be taken in<br />
grinding, that the direction where the *play<br />
of colors is<br />
visible is kept straight, and that it is cut in cabochon.<br />
The price of labrador is not very high, but soon after its<br />
discovery, a Doctor Anderson, having described the mineral<br />
as displaying all the variegated tints of color that are<br />
to be seen in the plumage of the peacock, pigeon, or most<br />
delicate humming-bird, and specimens having been carried<br />
to England, so great was the avidity to possess it, that<br />
small pieces were sold for twenty pounds sterling. The<br />
present price of good specimens is from two to ten dollars ;<br />
and a few years ago I purchased some letter-holders, which<br />
are beautiful specimens, for which I paid four dollars<br />
each. The largest specimens of labrador are in the col-<br />
lection of the Minerajogical Society, and in the museum of<br />
the Academy of Sciences at St. Petersburgh, which were<br />
found on the shore of the Pulkouka j<br />
one of them weighs<br />
(en thousand pounds. I have in my possession a rough
LABEADOE. 319<br />
specimen of the labrador of this State, merely rubbed off<br />
on the surface, and its colors, I venture to say, equal, if<br />
they do not indeed excel, in every respect, those of the<br />
specimens from St. Paul's Island ; and I anticipate the day<br />
when the citizens of New York will take as much pride in<br />
possessing labrador table and mantel slabs, as they now do<br />
in employing the Italian and Irish marble for these pur-<br />
to be inexhaustible in the<br />
poses ; for the resources appear<br />
rocky county of Essex. We do not see many specimens<br />
brought from the coast of Labrador, and I was informed<br />
by Mr. Audubon, on his return from that quarter, that he<br />
could not find any specimens. Mr. Henderson, of Jersey<br />
City, who presented me the above-mentioned rough specimen,<br />
had likewise splendid small polished specimens in<br />
breastpins, displaying all the properties in their full beauty.<br />
The same gentleman, who travelled last summer in com-<br />
pany with several scientific State geologists, mentions that<br />
they picked up beautiful specimens at the height of five<br />
thousand seven hundred feet above the level of the<br />
sea.<br />
In the collection of Columbia College is a fine specimen<br />
of labrador, brought from Gaspe, Lower Canada, by the<br />
Hon. Mrs. Percival.<br />
In 1799, it was announced" that in Russia* a labrador spar<br />
was discovered, where a perfect drawing and image of<br />
Louis XVI. could be distinctly traced, his head surrounded<br />
by a colored crown of pomegranate, with a rainbow border,<br />
and a silvery plume of azure color ; it was what may be<br />
called a lusus naturae. Count de Robassome, .formerly<br />
in the Russian service, was the possessor of this singular<br />
stone, and he demanded for the same, the sum of 250,000<br />
francs.<br />
There were some magnificent specimens, tables, and<br />
other ornaments, in the London Exhibition.
320 A POPULAR TREATISE ON GEMS.*<br />
In the New York Exhibition, were likewise fine speci<br />
mens exhibited from Labrador and the New York locality.<br />
HYPERSTHENE.<br />
This mineral was formerly annexed to hornblende, but<br />
has latterly been separated ; its name is derived from the<br />
Greek, and means of superior strength, in reference to<br />
the great hardness and specific gravity which it possesses.<br />
Hypersthene is found in crystalline masses it has an un-<br />
;<br />
even fracture ;<br />
it is opaque, and its colors are dark-brown,<br />
red, and greenish or grayish black ; the cleavage is parallel<br />
to the sides, and shorter diagonals of a rhombic prism ; its<br />
lustre is metallic, and when viewed in one certain direction,<br />
copper-red, light-brown, or gold-yellow, and in others it<br />
has a greenish play of colors. It scratches glass, has a<br />
darkish-green streak-powder, and has a specific gravity of<br />
3'38 ; it is easily fusible before the blowpipe on charcoal<br />
into a grayish-dark bead ; acids have no effect upon it ; it<br />
consists of magnesia, silex, alumina, and lime, with some<br />
water.<br />
It is found forming a constituent of the labrador rock,<br />
on the coast of Labrador, Greenland, and in the United<br />
States, on Brandywine creek in Pennsylvania, and in Essex<br />
county, New Jersey; fine specimens have been found in<br />
Hingham, Massachusetts. The French jewellers have lately<br />
begun to introduce this mineral for rings, pins, and other<br />
ornaments, on account of its high polish and beautiful<br />
color. The best-colored pieces are cut out of the mass,<br />
and ground on a lead wheel with emery in cabochon, and<br />
polished with rotten-stone. Beauty<br />
qualifications determine the price of this stone ;<br />
of color and other<br />
at Paris a<br />
hypersthene, in cabochon cut, eight to ten lines long and<br />
six lines broad, was sold for one hundred and twenty francs.
IDOCEASE. 321<br />
The mineral is, however, pretty rare, and has not yet<br />
been fully introduced.<br />
EDOCEASE.<br />
This mineral occurs mostly crystallized, in the form of a<br />
four-sided prism, terminated by four-sided pyramids ; also,<br />
massive ; its cleavage is parallel to all the planes of the<br />
prism ; it is transparent and opaque ; possesses strong<br />
double refraction of light ; its lustre is between vitreous<br />
and resinous ; its cross fracture conchoidal ; the crystals<br />
are all striated in length ; its colors are yellowish or<br />
brownish green, orange-yellow, sometimes blue and black.<br />
It scratches white glass and felspar, but is scratched by<br />
topaz. Its streak-powder is white, and it has a specific<br />
gravity of 3 '8 to 3*4. Before the blowpipe, it is fusible<br />
into a brownish glass. It consists of lime, alumina, silex,<br />
with some oxide of iron and manganese.<br />
Idocrase is found in different geological positions in<br />
primitive and volcanic rocks, in the cavities of the serpentine<br />
in the Alps, in Piedmont, Mount Soinma, Vesuvius,<br />
Etna ; also, Norway, Sweden, Spam ; in the United States,<br />
at Worcester, Massachusetts; Salisbury, Connecticut ; Cum-<br />
berland, Rhode Island.<br />
Idocrase, of pure green and brown colors, and transpar-<br />
ent, is used for rings and pins, and at Naples and Turin,<br />
it is principally cut for jewelry on a leaden wheel, and is<br />
polished on wood with pumice-stone. The forms it receives<br />
are the brilliant, table, and pavilion, and if perfectly pure,<br />
is mounted d jour ; otherwise with a suitable foil. The<br />
price of idocrase is not very high, as it is but little known<br />
among jewellers.<br />
Chrysolite and the green garnet are often substituted for<br />
but the first has a greater specific gravity and is<br />
HO<br />
idocrase ;
322 A POPULAR TEEATISE ON GEMS.<br />
of a more vivid color ;<br />
the latter is harder, and likewise of<br />
greater specific gravity.<br />
The Italian ido erase, which is cut at Naples, is mostly<br />
called the Italian chrysolite.<br />
HAUYNE.<br />
The name of this mineral was given in honor of the<br />
celebrated French mineralogist, the Abbe Hatiy. It occurs<br />
in dodecahedral crystals, with brilliant faces ; also, in grains<br />
and massive ; it has a conchoidal fracture ; is transparent<br />
and translucent ; possesses a strong vitreous lustre ; its<br />
structure is imperfectly foliated. Its colors are indigo, sky,<br />
and smalt blue ; also, white, green, gray, and black. It<br />
scratches white glass and is scratched by quartz; white<br />
streak-powder; specific gravity is 2*47. Before the blow-<br />
and with<br />
pipe it loses its color and fuses into a porous glass,<br />
borax into a diaphanous glass, which turns yellow on cool-<br />
ing; it forms a jelly ,<br />
with acids.<br />
It consists of lime,<br />
alumina, silex, protoxide of iron, sulphuric acid, and soda<br />
or potash.<br />
It is found in slacked basalt, and ejections of Mount Vesuvius<br />
; on Bodenmaise, on the Laach Lake, in Italy, and<br />
on the island of Tiree, Scotland.<br />
Hatiyne is not much known yet, but has lately been<br />
used for rings, ear-rings, brooches, &c. ; it is cut like ido-<br />
crase, but the price will always be high on account of its<br />
scarcity.<br />
LAPIS LAZULI.<br />
The name of this mineral is derived from the Persian<br />
language, and means blue color, or, with the Latin prefix,<br />
blue stone. The ancients were well acquainted with it,<br />
and have employed it as a substitute for other gems. The
LAPIS LAZULI. .323<br />
Greeks and Romans are said to have called it by the name<br />
of sapphire, denominating that with specks of iron pyrites<br />
the sapphirus regilus / Pliny called it the cyanus. It was<br />
formerly used as a strengthening medicine.<br />
Lapis lazuli very seldom occurs crystallized ; its regular<br />
form is the oblique four-sided prism ; it mostly occurs<br />
compact, and in grains and specks,<br />
with an uneven and<br />
conchoidal fracture; it is translucent on the edges; its<br />
lustre is nearly vitreous and shining ; structure foliated ; its<br />
color is fine azure-blue, with different shades, often inter-<br />
spersed with spots and veins of pyrites.<br />
It scratches glass,<br />
but is attacked by quartz and by the file ; its specific<br />
gravity is 2'3 ; before the blowpipe and on charcoal it with<br />
but with borax it fuses<br />
difficulty runs into a white glass,<br />
with effervescence into a limpid glass.<br />
It consists of lime,<br />
magnesia, alumina, and silex, with soda, protoxide of iron,<br />
and sulphuric acid.<br />
It is generally called in trade, the Armenian-stone.<br />
It is found in gangues of the older formations, and in<br />
Bucharia ; it exists in granite rocks, and is disseminated<br />
in all veins of thin capacity ; on the Baikal Lake it is found<br />
in solid pieces; also, in Siberia, Thibet, China, Chili, and<br />
Great Bucharia.<br />
Lapis lazuli is much used for jewelry, such as rings,<br />
pins, crosses, ear-rings, &c. The best pieces are generally<br />
cut out from larger lumps by means of copper saws and<br />
emery, then ground with emery on a lead wheel, and<br />
polished with rotten-stone on a tin wheel. The rocks<br />
which yield lapis lazuli, where it is contained in specks,<br />
are likewise cut for ornamental purposes, such as snuff-<br />
boxes, vases, candlesticks r cups, columns, cane-heads, &c. ;<br />
also, for architectural ornaments and stone mosaic; the<br />
larger specimens, having specks regularly disseminated on<br />
a white ground of the rock, are those selected for cutting.
324 A POPULAR TREATISE ON GEMS.<br />
The most important use of this mineral is that of furnish-<br />
ing the celebrated and beautiful pigment called ultramarine-<br />
blue, used by painters in oil, and said never to fade. The<br />
lapis lazuli takes a very high polish, but becomes dull again<br />
after being used for some time. It is sometimes imitated<br />
by lazulite' (azure-stone), or blue carbonate of copper, which,<br />
however, is not near so hard, and -effervesces- on testing<br />
with nitric acid. Those specimens having iron pyrites<br />
inclosed are difficult to polish well, on account of the un-<br />
equal hardness of the two minerals.<br />
Lapis lazuli has latterly been discovered in California,<br />
but the color of the mineral from this locality is very in-<br />
different, and its price is therefore much inferior to that<br />
from Persia. In Paris, the price is estimated at 300 francs<br />
per kilogramme. There are many engravings in lapis<br />
lazuli, such, for instance, as the Emblem of Peace a figure<br />
with a torch in one hand and a cornucopia in the other, and<br />
appearing to embrace military trophies, placed before her.<br />
The Chevalier d'Azara, Spanish minister in France, pos-<br />
sessed while there a very beautiful cameo of lapis lazuli,<br />
representing the head of Medusa, but without serpents.<br />
Maffei speaks of a Venus being carried by a she goat<br />
whipped by Love.<br />
The French crown-jewels contained some fine and gigantic<br />
specimens of lapis lazuli : one in the form of a boat of<br />
large dimensions, valued at 200,000 francs ;<br />
a sabre-handle<br />
given to Louis XVI., by Tippoo-Saib, valued at 6000<br />
a large vase, valued at 2600 francs.<br />
francs ;<br />
In 1855, at the Paris Exhibition, were numerous objects<br />
and carvings, exhibited by Rudolphi, which fairly compared<br />
with the antique relics of this species, both in material and<br />
in taste of execution.<br />
A marine shell carved from lapis lazuli was beautifully<br />
mounted by Morrel, and another chefcPoeuvre, in lapis lazuli,
LAPIS LAZULI. 325<br />
by Duponchel. A small round table of mosaic and lapis<br />
lazuli, which was a beautiful work by Jarry.<br />
A magnificent bagnivola of lapis lazuli, of very large size,<br />
and extremely pure and rich in color, was exhibited by Mr.<br />
Jones, in the London Exhibition, in 1851.<br />
Lapis lazuli has been well imitated of late, and, but for<br />
the touch, with much difficulty to be distinguished from<br />
the genuine, it is manufactured from bone-ashes and oxide<br />
of cobalt.<br />
The value of lapis lazuli, although depending upon its<br />
purity, intensity of color, and size, has nevertheless much<br />
diminished when compared with its former prices.<br />
. The Chinese, who have for a long time employed lapis<br />
lazuli in their porcelain painting, call the pure and skyblue<br />
stone zuisang, and the dark-blue, with disseminated<br />
iron pyrites, the tchingtchang, preferring the latter to the<br />
former ; they work the same for many ornaments, such as<br />
vases, snuff-boxes, buttons, and cups.<br />
In the palace which Catharine II. built for her favorite,<br />
Orlof, at St. Petersburg, there are some apartments entirely<br />
lined with lapis lazuli, which forms a most magnificent deco-<br />
ration. I have several slabs, three inches long, and of fine<br />
azure-blue color, in my possession.<br />
The production of ultramarine has been known since 1502,<br />
and was already employed, under the name of azurum ul-<br />
tramarinwtn, by Camillas Leonarus.<br />
The process of preparing ultramarine was known as<br />
early as the fifteenth century. The color is now mostly<br />
prepared at Rome, in the following manner : those pieces<br />
which are free from pyrites specks, are first calcined and<br />
pulverized ; the powder is then formed into a mass with a<br />
resinous cement (pastello), and fused at a strong heat this<br />
;<br />
is then worked with the hands in soft water, whereby the<br />
finest coloring particles are disengaged in the water,
326 A POPULAR TBEATISE ON GEMS.<br />
which will soon be impregnated with the blue color ; a fresh<br />
portion of water is then taken, and the same operation is<br />
continued until the remains are colorless. The ultramarine,<br />
after a short time, settles to the bottom of the vessels, and<br />
is carefully separated and dried. If the lapis lazuli be of<br />
the best quality, the product will be from two to three per<br />
cent. That color which remains yet in the mass is of an<br />
inferior quality, and is called the ultramarine ashes ; it is<br />
of a paler and more reddish color.<br />
Good ultramarine has a silky touch, and its specific gravity<br />
is 2*36. It does not lose its color if exposed to heat, but is<br />
soon discolored by acids, and forms a jelly. In order to<br />
distinguish the pure ultramarine from numerous spurious<br />
and adulterating coloring materials, such as indigo, Prus-<br />
to test the<br />
sian-blue, mineral-blue,
KTAJHTE. 327<br />
stuffs, several manufacturers have already<br />
been induced to<br />
engage largely in its preparation; and there is now a very<br />
extensive establishment in full operation by M. Guimet,<br />
three leagues from Lyons, who likewise claims the priority<br />
of its discovery: the royal porcelain manufactory at Meissen,<br />
in Saxony, also prepares it. The process" for making the<br />
artificial ultramarine, as it was first described by Gmelin, is<br />
here given, as it was published in the Annales de Chimie.<br />
The whole process is divided into three parts-:<br />
1. The pure hydrate of silica is prepared by fusing fine<br />
pulverized quartz or pure sand with four times its own<br />
weight of salt of tartar, dissolving the fused mass in water<br />
and "precipitating by muriatic acid ; also the hydrate of<br />
alumina is prepared from alum in solution, precipitated by<br />
ammonia.<br />
2. Dissolve the silex so obtained in a hot solution of<br />
caustic soda, and add to seventy parts of the pure silex<br />
seventy-two parts of alumina; then evaporate these substances<br />
until a moist powder remains.<br />
3. In a covered Hessian crucible, a mixture of dried sal<br />
soda, one part to two parts of sulphur, is heated gradually,<br />
until it is fully fused, and to the fused mass add small<br />
quantities of the earthy precipitate, taking<br />
care not to<br />
throw in fresh quantities until all the vapors have ceased ;<br />
after standing for an hour in the fire, remove the crucible,<br />
and allow it to cool. It now contains the ultramarine,<br />
mixed with an excess of sulphuret, which is to be removed<br />
by levigation ; and if the sulphuret is still in excess, it is<br />
to be expelled by moderate heat. Should the color not be<br />
uniform, levigation is the only remedy<br />
KYANTTE, SAPPAEE, DISTHENH.<br />
The name of this mineral is derived from the Greek,<br />
signifying blue, and was given to it on account of its blue
828 A POPULAR TREATISE ON GEMS.<br />
cc^or. It has been known for many centuries, having been<br />
cut by a Gernlan lapidary, Cornellius, in the reign of James<br />
I., under the name of sappare, by which it is yet known<br />
among the French jewellers.<br />
It occurs in masses composed of a confused aggregation<br />
of crystals, and in distinct crystals of four or eight sided<br />
prisms, much compressed, with two broad shining faces.<br />
The crystals are generally closely aggregated, and are cross-<br />
ing or standing on each other in a hemitropic form, so as<br />
to present a singular and curious aspect. Some of the<br />
crystals are curved, others are corrugated or wrinkled, as<br />
though they had been pressed endwise, or had not room<br />
to stretch themselves at full length ; others are pressed into<br />
triangular shapes, &c. It has a foliated structure ; uneven<br />
fracture ; is transparent and translucent ; possesses simple<br />
refraction of light ; its lustre is vitreous and pearly ; its<br />
colors are azure-blue, passing into light-blue or bluish-white<br />
and bluish-green. It scratches white glass, and is attacked<br />
by topaz or a good file ; yields a white streak-powder ; has<br />
a specific gravity of 3*63 to 3*67. It becomes electric by<br />
rubbing, and often exhibits positive and negative electricity<br />
in one and the same specimen; it is infusible before the<br />
blowpipe, but, with borax, fuses with difficulty into a trans-<br />
parent limpid glass : acids have no effect upon it.<br />
It consists of alumina and silex, sometimes combined<br />
with oxide of iron and water.<br />
The kyanite is found in micaceous, talcose, and argillaceous<br />
slate, at St. Gothard, in the Tyrol, and in Switzer-<br />
land; in Styria, Carinthia, Bohemia, Spain, and Siberia;<br />
also, in the United States, of the purest azure-blue color :<br />
large specimens in Litchfield, Haddam, and near New<br />
Haven (Connecticut) ; Chesterfield, Conway, Granville,<br />
Deerfield, and Plainfield (Massachusetts) ; Grafton, Nor-<br />
wich, and Bellows Falls (Vermont) ;<br />
Oxford (New Hamp-
TURQUOISE.<br />
shire) ; East Bradford, East Marlborongh,<br />
329<br />
smd Chester<br />
county (Pennsylvania) ; likewise, of a delicate light-blue,<br />
variously shaded, in Foster (Rhode Island).<br />
The kyanite has not yet been received as a favorite<br />
among the jewellers (perhaps from not being generally<br />
known by. them), or else it would long since have been<br />
cut for various ornamental purposes, more particularly in<br />
in this country, where the localities are so numerous and<br />
the color so beautiful. When well cut, it may be substituted<br />
for the sapphire. I indulge the hope that .some<br />
jewellers or lapidaries may take a hint from 4his remark.<br />
In France and Spain, it has for some years past been used<br />
for rings, brooches, and other jewelry. It is generally<br />
ground with emery on a lead wheel, and with pumice-ston.e<br />
polished on a wood plate, receiving the last polish with<br />
rotten-stone. The form it receives is cabochon or table<br />
cut. Usually, the best parts of good uniform colored specimens<br />
are picked out for cutting*<br />
The price of this stone depends upon the hardness, color,<br />
and polish : perfect specimens command a good price.<br />
Very fine cut specimens are brought from the East Indies,<br />
and sold in France as sapphires.<br />
TURQUOISE.<br />
The name of this mineral is probably derived from the<br />
country whence it was generally brought into market,<br />
which is Turkey. In ancient times it was used as a remedy<br />
for several diseases, and- was also worn as an amulet against<br />
disasters. It occurs in reniform masses and in specks;<br />
has a conchoidal fracture ; is opaque ; of a dull and waxy<br />
lustre ; its colors are blue and green, from sky-blue to<br />
apple-green, sometimes yellowish ;<br />
it scratches apatite, but<br />
not quartz nor white glass, and is easily attacked by the
330 A POPULAR TREATISE ON GEMS.<br />
file ; it has a white streak-powder ; its specific gravity is<br />
2'86 to 3*0; "it is infusible before the blowpipe alone, but<br />
loses its blue color and . becomes yellowish-brown but ; it<br />
fuses with borax into a limpid glass.<br />
Muriatic acid has no<br />
effect upon it. Consists of alumina, phosphoric acid, water,<br />
oxide of copper, and protoxide of iron.<br />
There are two kinds of turquoise used in trade, which<br />
differ materially in their composition, and are from differ-<br />
ent localities :<br />
1. Turquoise from the old rock, or true turquoise, which<br />
is generally . called Oriental turquoise, we receive from<br />
Persia, and is of a sky-blue and greenish color.<br />
2. Turquoise from the new rock, the occidental or bone<br />
and tooth turquoise, which is either dark-blue, light-blue,<br />
or bluish-green ; the surface of this mineral is sometimes<br />
traversed by veins which are lighter than the ground ;<br />
it is<br />
of organic origin, consisting, probably of colored teeth of<br />
antediluvian animals ; it owes its color, according to Bouil-<br />
. ' . ' O<br />
Ion Lagrange, to two per cent, of phosphate of iron, which<br />
is contained in it. It is easily distinguished from Oriental<br />
turquoise by its structure, internally foliated and striated,<br />
which is an indication of a bony composition ; it does not<br />
take so high a polish, is discolored in distilled water, dis-<br />
solves in acids, and is totally destroyed by aquafortis. Its<br />
localities are Siberia, Languedoc in France, and other<br />
places.<br />
True or Oriental turqupise is found in small gangues of<br />
bog-ore and silicious schist, in boulders, &c. A mineral<br />
by the name of kalaite, occurring as a coating to silicious<br />
sinter, in Silesia and Saxony, was some years ago dis-<br />
the mer-<br />
covered. Turquoise is brought to market by<br />
chants, of Bucharia, ready cut and polished; and in Mos-<br />
cow'it is wrought over, being ground on a lead wheel with<br />
emery, and polished with rotten-stone or pumice-stone on a
TURQUOISE.<br />
331<br />
tin wheel ; and its last and best polish is received from the<br />
jewellers, by rubbing with a linen rag and rouge. Since it<br />
is often traversed by fissures and cracks in the interior,<br />
it requires great caution in grinding. It is mostly cut in<br />
the form of cabochon ; also, as thick or table stones, and is<br />
used for numerous purposes in jewelry, such as rings, ear-<br />
rings, brooches, and also for mounting around the most<br />
precious gems.<br />
The price of turquoise has, for the last ten years, much<br />
decreased ; that of an Oriental is generally four times<br />
is worth<br />
higher than the occidental: one the size of a pea<br />
about five dollars; a good turquoise, sky-blue and oval-cut,<br />
five lines long and four and a half lines broad, was sold in<br />
France for two hundred and forty-one francs ;<br />
and a light-<br />
blue, greenish lustre, and oval-cut, five and a half lines long<br />
and five broad, was sold for five hundred francs ; whereas<br />
an occidental turquoise, four lines long and three and a half<br />
broad, brought only one hundred and twenty-one francs.<br />
Turquoise is very well imitated artificially (so much so as to<br />
render it difficult to discover the difference between that and<br />
the real), by adding to a precipitated solution of copper and<br />
spirits of hartshorn, finely-powdered and calcined ivory-<br />
black, and leaving the precipitate to itself for about a week,<br />
at a moderate heat, and afterwards carefully drying the<br />
same, and exposing to a gentle heat. This artificial tur-<br />
quoise is softer than the real, and cuts with a knife in<br />
shavings, whereas the genuine yields a white powder. The<br />
real turquoise displays in the daytime a sky-blue, and at<br />
night a light and greenish color ;<br />
and resists the fire.<br />
is not attacked by acids,<br />
In the museum of the Imperial Academy at Moscow, is<br />
a turquoise more than three inches in length and one inch<br />
in breadth.<br />
A jeweller at Moscow is said to have had in his posses-
332 A POPULAR TREATISE ON GEMS.<br />
sion a turquoise two inches long, in* the form of a heart.<br />
This formerly belonged to Nadir Shah, who wore it as aE<br />
amulet, for which he asked five thousand rabies.<br />
A short time ago, I beheld, at a sale, one of the largest<br />
and most splendid turquoises, which was one inch in size,<br />
and of a blue color.<br />
Major McDonald's collection of turquoises, from Arabia,<br />
exhibited at the London Exhibition, in 1851, was very<br />
beautiful ; it consisted of two hundred specimens, cut and<br />
polished. They differed very little from the Persian tur-<br />
quoises. He discovered several localities in the country of<br />
Sonalby, sixteen days' journey northeast of Suez, but all<br />
were within a range of forty miles, and upon a mountain<br />
range, at from five thousand to six thousand feet of elevation.<br />
Some turquoises were found in situ, but most of them<br />
were collected from the ravines descending the mountain<br />
chain. The rock is a reddish sandstone, composed of quartz<br />
grains, belonging to the paleozoic rocks. Their hardness<br />
is equal to that of agate. The nodules of turquoise form<br />
groups, almost like currant seeds, in the sandstone. There<br />
may be observed in this collection, veins and small concretions<br />
from one tenth to one twentieth of an inch in thick-<br />
ness, which cut across the bed of sandstone like small<br />
threads ; in color they vary from an intense blue to a bluish-<br />
white.<br />
NATROLITE.<br />
This mineral has been discovered of -late years, and re-<br />
ceives its name from the Latin natron, soda, given to it on<br />
account of that alkali being, contained in it; it occurs reni-<br />
form, botryoidal, and massive, such as mammillary, and in<br />
the alternate zones around the centre; it has a splintery<br />
fracture; is translucent on the edges; of a pearly lustre:<br />
its colors are white, yellowish-white, or reddish-brown, and
they often alternate in different layers ;<br />
glass, but is scratched by felspar;<br />
powder; its specific gravity is 2*16;<br />
blowpipe into a colorless* spongy glass ;<br />
FLUOR SPAR. 333<br />
it scarcely scratches<br />
has a white streak-<br />
it fuses before the<br />
it consists of soda,<br />
alumina, silex, and water, sometimes a little oxide of iron.<br />
Its localities are Switzerland, Bohemia, Saxony, Scotland,<br />
and Nova Scotia. Natrolite, on abcount of its susceptibility<br />
of a high polish, has been used for rings and other<br />
ornaments in jewelry, but has not yet been hi much de-<br />
mand, and its value is also very inconsiderable.<br />
FLUOR SPAR.<br />
This mineral was well known to the ancients, but did not<br />
attract particular attention until the sixteenth century,<br />
when it was introduced as a flux. As early as 1670, the art<br />
of etching on glass by means of fluor spar was practised at<br />
Nuremberg.<br />
Fluor spar occurs mostly in crystals of various forms, the<br />
principal of which is the octahedron with its varieties, the<br />
cube and the rhomboidal dodecahedron ; also, massive and<br />
in specks ; it has an uneven or splintery fracture ; is trans-<br />
parent or translucent on the edges ; possesses simple refraction<br />
of light ; a vitreous lustre ; its colors are green, yellow,<br />
gray, blue, and white ; also purple and red, in all their<br />
various shades, from the violet to the rose-red.<br />
It scratches lime, but not glass ; yields to the knife ; has<br />
a white streak-powder; its specific gravity is 3*14 to 3'17;<br />
it becomes electric by rubbing ;* before the blowpipe it<br />
fuses with ebullition into an opaque globule, but with<br />
when pulverized and treat-<br />
borax, into a transparent glass ;<br />
ed with heated sulphuric acid, it emits fluoric acid gas,<br />
which is employed in etching on glass ; phosphoresces when<br />
thrown on hot iron ; it consists of fluoric acid and lime.
834 A POPULAR TREATISE ON GEMS.<br />
From the variety and beauty of its colors, it is known, when<br />
cut, in trade, under the various names of false emerald,<br />
false amethyst, false ruby, and false topaz, according to the<br />
color it exhibits. It is mostly found in metalliferous veins,<br />
and very rarely in the newer formations. Its localities are<br />
in Baden, Bohemia, Saxony, St. Gothard, at Derbyshire<br />
and Devonshire, in England, and the United States, in the<br />
last of which countries it occurs of most beautiful colors in<br />
fine crystals ; from a lately-discovered locality at Rnssy, in<br />
St. Lawrence county, State of New York, I have specimens<br />
of crystals two feet long and five wide. It is found in Illi-<br />
nois, seventeen miles from Shawneetown ; Blue Ridge,<br />
Maryland ; Smith county, Tennessee ; at Franklin Furnace,<br />
and Hamburgh, New Jersey; Saratoga Springs, and at<br />
Alexandria, New York; Middletown and Huntingdon,<br />
Connecticut ; Thetford and Southampton lead mines, Mas-<br />
sachusetts, and on the White Mountains, New Hampshire.<br />
Fluor spar is cut for ring-stones and shirt-buttons, and<br />
particularly<br />
in such forms as are intended to be substituted<br />
in Derbyshire there have been large mills<br />
for other gems ;<br />
for grinding, cutting, and polishing the flour spar into vases,<br />
cups, obelisks, plates, candlesticks, &c., ever since 1765,<br />
and there are now more manufactories, principally at<br />
Derby. That fluor spar which may be called the nodular<br />
variety, and the colors of which run in bands or zones, is<br />
only found in a single mine near Castleton, Derbyshire, and<br />
is known by the technical name of Derbyshire-spar<br />
John ; it is used for various ornaments,<br />
or Blue<br />
to be met with all<br />
over the world, in parlors or mineral collections. In order<br />
to heighten the various colors in the ornamental specimens,<br />
before they are polished, they are heated to a certain de-<br />
gree, when the dark spots, or tints, disappear, and the<br />
colored bands become more distinct, and assume a peculiar<br />
purple or amethystic hue.
MALACHITE. 335<br />
Fluor spar is often intermixed with lead ore, called galena,<br />
which produces, when polished, a beautiful appearance.<br />
Ornaments of fluor spar still command a high price, which,<br />
however, depends a good deal on the perfect qualities of<br />
the various specimens, their color, gize, &c.<br />
A translucent variety of fluor spar, called chlorophane<br />
(found in Cornwall, England, in Siberia, and principally in<br />
the United States, at New Stratford, Connecticut), is of<br />
beautifully variegated colors, but principally blue, violet, and<br />
green ; it is chiefly interesting on account of its phosphorescence<br />
; when put on hot iron in a dark room, it emits a<br />
most beautiful emerald-green light.<br />
One of the first locali-<br />
ties of chlorophane discovered in this country, was at Shee-<br />
konk, Massachusetts, near the summer residence of the<br />
Hon. Tristam Burges, about one and a half miles from*<br />
Providence. It is massive, opaque, and of a deep purple<br />
color. It phosphoresces readily on being projected upon a<br />
moderately-heated shovel, when it loses its color and becomes<br />
white. It also occurs of a crystalline structure in<br />
Wrentham, Massachusetts, near the Cumberland and Rhode<br />
Island line, in the vicinity of Diamond Hill. A beautiful<br />
vase of Derbyshire-spar, as also crystalline groups, may<br />
be seen in the collection of the New York Lyceum of<br />
Natural History.<br />
MALACHJTE.<br />
The name of this mineral is from the Greek, alluding to<br />
its color ; it was well known to the ancients ; Theophrastus<br />
called it the pseudo-emerald ; it was worn by many as<br />
an amulet.<br />
It occurs tuberose, globular, reniform, mainmillary, an
336 A POPULAR TREATISE ON GEMS.<br />
lustre ;<br />
and has an emerald or verdigris green color, alter-<br />
nating sometimes in stripes of different shades of green.<br />
It scratches lime, but not glass ; its streak-powder is of<br />
lighter color than the mineral; its specific gravity is 3*67 ;<br />
before the blowpipe, it decrepitates and turns black ; with<br />
borax, it is reduced to a* metallic grain ;<br />
it effervesces with<br />
nitric acid ; is dissolved, and forms a blue color with am-<br />
monia ; it consists of oxide of copper, carbonic acid, and<br />
water.<br />
Malachite is found in various rocks, primitive as well<br />
as secondary, in gangues and strata. The finest specimens<br />
are obtained in Siberia, Tyrol, France, Hungary, Norway,<br />
Sweden, England, Bohemia, and the United States, at a<br />
great number of localities, but either in small specimens,<br />
*or as a coating of other copper ores, which will ever ren-<br />
der jt useless for ornamental purposes. The principal locali-<br />
ties in this country are in New Jersey, Maryland, Connecti-<br />
cut, and at the various copper-mines ; it is also found in the<br />
island of Cuba, from which place I have seen some good<br />
compact specimens.<br />
Some very fine specimens of compact malachite from<br />
Siberia, were presented to the New York Lyceum of<br />
Natural History, by' Charles Cramer, Esq., of St. Petersburg.<br />
I have also seen some excellent specimens of mala-<br />
chite in the collection of Dr. Martin Gay, at Boston ; Dr.<br />
Chilton, of New York, &c.<br />
Malachite, when cut, takes a high polish,<br />
which well<br />
adapts it for various ornaments, such as rings, pins, earrings,<br />
&c. Snuff-boxes, candlesticks, mosaics, &c., are likewise<br />
made from it. In general, the specimens are assorted,<br />
and the best pieces cut on a leaden wheel with emery, and<br />
polished with rotten-stone on a tin plate.<br />
cirnens are used for table plates and vases.<br />
Very large spe<br />
The value of the malachite is not high, being very abun-
MALACHITE. 337<br />
dant ; yet much depends upon the size of the various specimens.<br />
At St. Petersburg, a very large slab, said to be<br />
in the collection formerly belonging to Dr. Guthrie, thirtytwo<br />
inches long, seventeen inches broad, and two inches<br />
thick, was valued at twenty thousand francs. Many rooms<br />
in several European palaces are laid out with malachite ;<br />
and the Mineralogical Museum, at Jena, possesses a large<br />
collection of malachite, which was presented by the Grand<br />
Duchess of Saxe Weimar, a Russian princess.<br />
An apartment in the Grand Trianon, at Versailles, is<br />
furnished with pier and centre tables, mantel-pieces, ewers<br />
and basins, and enormous ornamental vases of malachite,<br />
the gift of the Emperor Alexander to Xapoleon.<br />
The malachite furniture exhibited by the Russian government<br />
at the London Exhibition, excited so much admira-<br />
tion and was sold at such high prices, that the author con-<br />
siders himself justified in copying a part of the report by<br />
the jury on inlaid work in malachite :<br />
" Malachite is a peculiar mammilla ted or stalagmitic form<br />
of the green carbonate of copper, chiefly found in an avail-<br />
able state for inlaid work, in a very few localities in<br />
Siberia, and lately in South Australia. It has long been<br />
employed in Russia in this manufacture. The mineral is<br />
remarkable for its fine emerald-green color (often present-<br />
ing several distinct shades in the same specimen), its bril-<br />
liant and silky lustre, and compact texture. It is softer<br />
than marble, very much heavier, and by no means so easily<br />
worked, owing to its brittleness and the concentric arrangement<br />
it generally presents. It can rarely be found in<br />
masses weighing more than ten to twenty pounds, and<br />
good specimens have a very high value, as the finer kinds<br />
are used exclusively for decorative purposes.<br />
" The most important locality at present known for the<br />
finer kinds of Siberian malachite, is in the copper ground
338 A POPULAR TREATISE ON GEMS.<br />
of Nijug Tagilsk, in the government of Ekaterinenburg, on<br />
the river Tura, a tributary of the Irtish, on the Siberian side<br />
of the Uralian mountains, in latitude 57J N., longitude 56<br />
E. In a mine at this place, belonging to Messrs. Demidoff,<br />
Sir Roderick Murchison has described an immense mass of<br />
malachite, which at the time of his visit, a few years back,<br />
had been recently discovered at the depth of two hundred<br />
and eighty feet, strings of green copper conducting to it ;<br />
and these strings increasing in width and value, were found<br />
to terminate in a vast irregular botryoidal mass, estimated<br />
to contain not less than half a million of pounds of this<br />
valuable mineral. The larger blocks, when exposed to the<br />
air, break up into smaller fragments, rarely weighing more<br />
than from one to four pounds.<br />
" It is by no means a modern application of this material,<br />
to employ it in inlaying or veneering for decorative purposes;<br />
and few palaces or large public museums in the<br />
principal capitals of Europe, are without specimens, mark-<br />
ing the progress of its manufacture from time to time, and<br />
generally regarded, from their great rarity, cost, and beauty,<br />
as worthy of being made imperial and royal presents. It<br />
is, however, only lately that Messrs. Demidoff, the owners<br />
of the mine in which the mineral occurs, have established<br />
in St. Petersburg a manufactory, where, after numerous<br />
trials and the expenditure of much capital, labor, and in-<br />
such works<br />
genuity, it has been found possible to produce<br />
as those sent to the London Exhibition, and in testimony<br />
of the magnitude and importance of the objects exhibited,<br />
their extraordinary beauty and richness, the excellence of<br />
the production, and the application of the various new<br />
methods of manufacture, Messrs. Demidoff have been<br />
awarded the highest premiums. These are chiefly seen in<br />
the construction of the doors, and more especially in the<br />
ingenious and beautiful manner in which the pattern is
MALACHITE. 339<br />
adapted to the material, the detached pieces of mineral<br />
being fitted to each other so as to preserve the pattern ;<br />
they may also be noticed in the nature of the cement,<br />
which being mixed with broken fragments of the malachite<br />
itself does not interfere with the plan, or in any way injure<br />
the effect of the whole.<br />
"<br />
The working of malachite on a large scale is extremely<br />
tedious and laborious, and the mode of operation is too<br />
long to detail in this treatise.<br />
" The quantity of malachite obtained from the mine and<br />
brought into market annually is very small, and the price<br />
of the raw material is considerable, it ranges from twelve<br />
to seventeen shillings sterling per pound, according to color<br />
rather than veining, the darker colors being cheapest;<br />
there are four shades quoted, denominated respectively,<br />
foncee, ordinaire, claire, and pale ; but these are also sub-<br />
divided, the two first into ronde and longv.e, the others<br />
into ronde, longue, and tachetee. A large proportion of<br />
the malachite in the specimens exhibited was of very good<br />
color, and the average value probably exceeded fifteen<br />
shillings sterling per pound.<br />
"The objects exhibited consisted of a pair of fold-<br />
ing-doors, several vases, a chimney-piece, a table, a set of<br />
chairs, and sundry smaller articles; of these, the doors and<br />
vases were at once the most important and the most highly<br />
finished, and it is understood that the former required the<br />
constant labor of thirty workmen employed by day and<br />
night during a whole year. They were most skilfully and<br />
and beautifully planned, and the workmanship was in all<br />
respects admirable."<br />
There are fluted Corinthian columns of malachite in<br />
some churches in St. Petersburg, and many other large<br />
ornaments of large slabs of malachite in the palace of the<br />
King of Prussia, at Potsdam.
340 A POPULAR TREATISE ON GEMS.<br />
A large oblong table, inlaid with malachite, partly Russian<br />
and partly Australian, was also exhibited by a manufacturer<br />
of Paris, with specimens of azurite (blue carbonate<br />
of copper), but were all put in the shade by the Russian<br />
articles.<br />
SATIN SPAR.<br />
This mineral occurs stalactiform, globular, reniform, and<br />
massive ; it is of a fibrous texture (that is, of fine delicate<br />
fibres closely adhering together), a pearly lustre, and is<br />
translucent on the edges ; the colors are snow-white, yel-<br />
lowish-white, or pale-red, colored by<br />
metallic oxides. It<br />
scratches gypsum, but not glass ; specific gravity, 2*70 ; be-<br />
comes electric by rubbing ; before the blowpipe is infusible,<br />
and changes into quicklime, but borax reduces it to a clear<br />
glass. It effervesces and dissolves with nitric acid; and<br />
consists of lime and carbonic acid. Satin spar is called by<br />
mineralogists fibrous limestone, and is found in the coal<br />
formations, and in the cavities of several limestones. The<br />
finest specimens are found in Cumberland and Derbyshire,<br />
England ; in Hungary ; and in the United States, near<br />
Baltimore, in Pennsylvania, also at Westfield and Newburyport,<br />
Massachusetts, where splendid specimens five inches<br />
long are obtained, according to Professor Hitchcock. It<br />
takes a fine polish, and is distinguished by its extraordinary<br />
fine satin lustre, and is therefore used for various articles of<br />
jewelry, such as ear-rings, necklaces, beads, and also for<br />
inlaid work ; large specimens are used for snuff-boxes.<br />
Satin-spar beads have been in great favor as necklaces<br />
and ear-rings, and were sold a few years ago in England at<br />
very high prices. In modern times, the satin beads or<br />
pearls have been imitated to a great extent in France and<br />
Germany, in white and deep-yellow colors : glass beads, of<br />
a bluish-white tinge, and hollow, are made to imitate the
ALABASTER. 341<br />
reflection of the satin spar, by means of the scales of a<br />
small river-fish called the bleak, that are suspended in dissolved<br />
isinglass, and dropped into the bulbs, which are then<br />
turned in all directions in order to spread the solution<br />
equally over their interior surface ; in this way the glass<br />
bulbs assume the natural color and brilliancy of satin spar ;<br />
they are harder, however, and it is easy to detect them on<br />
that account.<br />
Fine specimens may be seen at the New York Lyceum<br />
of Natural History, also in the collection of Dr. Gay, of<br />
Boston.<br />
Satin gypsum, which bears the greatest resemblance to<br />
satin spar, and only differs in its chemical constituents (hav-<br />
ing sulphuric acid, instead of carbonic, as a component part),<br />
is much used for the same kind of ornamental purposes, and<br />
is more abundant over the world. I have seen very splen-<br />
did specimens at South Boston, in the beautiful collection<br />
of minerals belonging to Francis Alger, Esq., who brought<br />
them from Nova Scotia, and who (as also Dr. C. T. Jack-<br />
sou) has given so valuable a description<br />
treasures of that province.<br />
of all the mineral<br />
Satin gypsum is, however, much softer than satin spar,<br />
and is much easier scratched ; for which reason it is not<br />
so generally employed.<br />
ALABASTER.<br />
This mineral is a compact gypsum, and occurs massive,<br />
with a compact fracture ; it is translucent ; has a glim-<br />
mering lustre, and its colors are white, reddish, or yellowish.<br />
The purest kinds of this mineral are used in Italy for<br />
vases, cups, candlesticks, and other ornaments. It is found<br />
at Castelino, in Tuscany, thirty-five miles from Leghorn,<br />
at two hundred feet below the surface of the earth.
342 A POPULAR TREATISE ON GEMS.<br />
The yellow variety, called by the Italians, alabastro ago*<br />
tato, is found at Sienna ; another variety of a bluish color,<br />
obtained at Guercieto, is remarkably beautiful, being<br />
marked with variegated shades of purple, blue, and red.<br />
The above alabasters are carbonates of lime.<br />
The principal manufactory of alabaster ornaments is at<br />
Valterra, thirty-six miles from Leghorn, where about five<br />
thousand persons live by this kind of labor. In making,<br />
they require great care, and must be preserved from dust,<br />
as the alabaster is difficult to clean. Talcum, commonly<br />
called French chalk, will remove dirt, but the best mode<br />
of restoring the color, is to bleach the alabaster on a grassplat.<br />
Gum water is the only cement for uniting broken<br />
parts.<br />
Plaster of Paris is likewise, a compact gypsum, but<br />
contains a small portion of carbonic acid, which makes it<br />
effervesce when treated with acids. It was formerly ex-<br />
ported only from Montmartre, near Paris, hence its name ;<br />
it is much used in ornamenting rooms in stucco, in taking<br />
impressions of medals, in casting statues, busts, vases,<br />
time-piece stands, candelabras, obelisks, and for many other<br />
purposes.<br />
The common plaster of Paris is ground after being cal-<br />
cined ;<br />
and in this condition it has the property of forming<br />
a pliable mass with water, which soon hardens, and assumes<br />
the consistency of stone.<br />
Oriental alabaster is not a sulphate but a true carbonate<br />
of lime, and on account of its peculiar tint and trans-<br />
parency, and as it appears<br />
that it was formed similar to<br />
stalagmite, it was called by the ancients, alabaster; the<br />
large vase of this Oriental alabaster which was so justly<br />
and so much admired by the thousands of spectators at the<br />
London Exhibition, was executed by Dallamada, of Rome.<br />
It was really a magnificent piece of workmanship, being
AMBEE. 348<br />
from a large block and the whole work of one entire piece,<br />
the vase, the handles, which consisted of serpents, along<br />
with the tazza and the extremely fine polish, displayed the<br />
great ingenuity of the master.<br />
A hollow altar of Oriental alabaster, provided with a<br />
lamp and intended to show the remarkable transparency<br />
of the material, and of excellent workmanship, along with<br />
a great many statues and groups of life-size figures, were<br />
exhibited both in the London and New York Exhibi-<br />
tions.<br />
A3IBER.<br />
This gem was known to the inhabitants of remote ages ;<br />
the Phoenicians sailed to the Baltic (the Glessany islands),<br />
for the sole purpose of obtaining amber, which they<br />
wrought into chains and other ornaments, that were sold<br />
to the Greeks, who called the same electron. In the Trojan<br />
war, as Homer reports, the women wore necklaces of<br />
amber. Its electric properties were likewise known, for<br />
Thales was so much surprised at that phenomenon, that he<br />
attributed it to a soul in the amber ; and Pliny says that<br />
amber is revived by heat, the nature of electricity not<br />
being understood. It was also worn as an amulet, and<br />
used for medicine. The ancients could not agree as to its<br />
origin : Philemon, according to Pliny, classed it as a fossil ;<br />
Tacitus, however, judging from the insects held in it, concluded<br />
it must be a vegetable juice, whence its name in<br />
Latin, succinum, or juice. Many naturalists have, until<br />
lately, considered amber as a mineral;<br />
but it has been<br />
satifactorily proved by Schweigger and Brewster, from its<br />
chemical characters, and polarizing light, to be a gum-resin,<br />
and that it is the juice of a tree, called the amber-tree, now<br />
extinct.<br />
Amber occurs in nodules or roundish masses, from the
344 A POPULAR TREATISE ON GEMS.<br />
size of grains to that of a man's head ; and sometimes in<br />
specks; it has a conchoidal fracture; is transparent and<br />
translucent ; possesses single refraction of light ; a resinous<br />
lustre in a high degree : its colors are wine and wax<br />
yellow, greenish or yellowish white, or reddish-brown ;<br />
sometimes the colors vary in layers. It scratches gypsum,<br />
but is attacked by carbonate of lime ; its streak-powder is<br />
yello wish-white ; it has a specific gravity of 1*08 to 1*10;<br />
it becomes electric by rubbing. Before the blowpipe it<br />
burns with a yellowish and bluish green flame, emitting at<br />
the same time a dense and agreeable smoke, and leaving a<br />
carbonaceous residuum;<br />
heated oil softens and makes it<br />
pliable ; it does not melt as easily as other resins, requiring<br />
51 7 Farenheit ; it yields by dry distillation an acid which<br />
is called succinic acid, also an essential oil, known by the<br />
name of oil of amber, and in the retort remains a brown<br />
mass, called the resin of amber, which is used in the arts<br />
as amber varnish ; any essential oil, or spirits of turpentine<br />
may be used for procuring the resin ;<br />
fat oils dissolve<br />
amber perfectly; its elementary constituents are carbon,<br />
hydrogen, and oxygen, with some lime, alumina, and<br />
silex.<br />
Amber is found either thrown up by the sea, or in the<br />
small rivers near it ;<br />
sometimes in alluvial deposits of sand<br />
or gravel in the vicinity of the sea, or in bituminous forma-<br />
tions, such as lignite, bituminous wood, or jet, where crystallized<br />
minerals are at the same time found, such as iron<br />
pyrites, &c.<br />
Its geological distribution is in the green-sand formation,<br />
or, according to De la Beche, the stratified rocks, between<br />
the third and fourth large group.<br />
Amber occurs in the greatest abundance on the Prussian<br />
coast, in a bed of bituminous coal, where it is washed out<br />
or cast ashore during the autumnal storms on the coast of
AMBER. 345<br />
Pomerania and Prussia proper, between Konigsberg and<br />
Dantzic ; it is also obtained there by sinking<br />
a shaft into<br />
the coal, and is mined in a systematic way. All along the<br />
line of the Baltic coast, at Corn-land, Livonia, Pomerania,<br />
and in Denmark, it is picked up. On the Sicilian coast,<br />
near Catania, sometimes very peculiarly tinged blue, it is<br />
also found. In Greenland, at Hasen island, it occurs in<br />
brown coal. Near Paris it occurs in clay. It is also found in<br />
China. One of the largest specimens ever met with on the<br />
Baltic was found in 1811, measuring fourteen inches in<br />
length by nine inches in breadth, and weighing twenty-one<br />
pounds.<br />
I had in my own coUection, in the year 1831, a splendid<br />
wax-yellow amber, from the Baltic, which measured about<br />
sixty cubic inches, and weighed nearly two pounds. It is<br />
also found on the Danish coast, and in Greenland, Sicily,<br />
Monrovia, Poland, France, and the West Indies. A sailor<br />
is said to have found a remarkable specimen, eighteen<br />
inches in length, in a singular manner ;<br />
the discoverer acci-<br />
dentally seated himself on it, when he became so attracted<br />
to the amber, excited by his natural heat, that it was with<br />
some difficulty he could detach himself from it.<br />
In the United States we find amber at Cape Sable, in<br />
Maryland, in a bed of lignite,<br />
in masses of four and five<br />
inches diameter ; also, near Trenton, and at Camden, New<br />
Jersey, where a transparent specimen,<br />
several inches in<br />
diameter, was found. According to Professor Hitchcock,<br />
it is found at Martha's Vineyard, Gayhead, and at Nantucket.<br />
At the latter place, a light-colored specimen was<br />
found, of three or four inches diameter, which is<br />
collection of T. A. Green, Esq., of New Bedford.<br />
in the<br />
The production of amber depends upon the position of<br />
the respective localities ; whether it is found among sand<br />
and gravel, in mines called amber mines, or in the sea, on
346 A POPULAR TREATISE ON GEMS.<br />
the shore, or in smaller rivers near the sea-coast ; and the<br />
modes of collecting are threefold :<br />
1. The amber mines, which are numerous in Prussia, are<br />
wrought like other mines, and explored to a depth of more<br />
than one hundred feet. Shafts are constructed for raising<br />
the product from the interior of the mines ; the miners dig<br />
until they reach the amber vein, which is generally found<br />
after passing a stratum of sand and a bed of clay of twenty<br />
feet thickness, and another stratum of decomposing trees or<br />
come then to<br />
lignite, which may be fifty feet through ; they<br />
the pits, which the characteristic color of the soil is the best<br />
indication to search for.<br />
2. The second mode of collecting amber is practised,<br />
generally after a storm, by the fishermen, who either wade<br />
into the water, provided with leather dresses,<br />
to their<br />
necks, or use small boats, and find at the depth of three<br />
fathoms the floating amber.<br />
3. It is mostly, however, collected in large quantities on<br />
the shore, after having been thrown up by severe storms.<br />
The amber fishermen are, by practice, pretty well skilled<br />
in finding out the spots where the largest quantities may<br />
be obtained.<br />
Amber from the mines does not essentially differ from<br />
that of the sea, excepting that the former is rather more<br />
brittle, and is often covered with an earthy crust.<br />
The amber is assorted before it comes into the hands of<br />
the lapidary or merchant, and according to size and clear-<br />
ness of color, it receives different technical names. Thus,<br />
there are<br />
1. The exquisite specimens, which are perfectly pure,<br />
transparent, and compact, weighing from five to six ounces<br />
or more ; these are employed in larger ornaments and spe-<br />
cimens of the arts, and bring the highest price.<br />
2. The ton stones, which weigh from a quarter of an
AMBER. 347<br />
ounce to four ounces; the largest or purest pieces of which<br />
are used for jewelry, and the impure for incense or med-<br />
icine.<br />
3. The nodules are still smaller.<br />
4. The varnish stones are still smaller than the former,<br />
but are very pure and hard, so as to be easily pulverized,<br />
and are used for varnishes, sealing-wax, &c.<br />
5. The sandstones are very small, opaque, and perforated<br />
pieces.<br />
6. The lumps are large but impure specimens, unfit for a<br />
lapidary's use ; they are sold as specimens, or employed as<br />
incense, or for the manufacture of succinic acid.<br />
7. Refuse are those pieces which fall off at the lapidary's<br />
bench.<br />
The pure amber receives from the lapidary distinct<br />
such as<br />
names, according to the shades of color it possesses,<br />
egg, pale, and light yellow, and so into its brownish shades.<br />
The assorted amber is treated according to the various<br />
purposes it is intended for, and receives its requisite form<br />
by cleaving with an appropriate instrument, by which, also,<br />
the external crust is removed. It is generally believed that<br />
the worse the crust is in appearance, the more beautiful is<br />
the interior of the amber.<br />
Amber, taking a very high polish, is employed<br />
for a<br />
great many purposes of jewelry, and for various ornaments,<br />
such as beads, necklaces, bracelets, ear-rings, buttons, rosa-<br />
ries, mouth-pieces for pipes, cane-beads, snuffboxes, work-<br />
boxes, &c. It is generally wrought on the turner's lathe,<br />
by steel instruments, and is easily bored ; it is polished on<br />
a leaden wheel, with pumice-stone, then with linen or a hat-<br />
body and rotten-stone, and lastly by rubbing it with the<br />
hand. Common specimens are polished with a linen rag,<br />
chalk, and water. Beads of amber must be drilled before<br />
receiving the facets. In cutting and working amber, care
348 A POPULAR TREATISE ON GEMS.<br />
must be taken not to overheat it by friction, as it will then<br />
be liable to crack. Amber has occasionally been cut into<br />
cameos, busts, images,
AMBER. 349<br />
little; whereas copal, under similar circumstances, melts<br />
and falls in drops, which become flattened." My own ex-<br />
perience has taught me the following distinguishing charac-<br />
teristics : first, the electrometer, a small instrument com-<br />
posed of a brass needle, suspended on a pin, is the most esse^<br />
tial distinguishing guide, for amber, on being rubbed,<br />
will excite the instrument about ten degrees more than<br />
copal ; secondly, amber, on being brought before the fire,<br />
requires a moderately high temperature for melting it, and<br />
exhibits no kind of ebullition, whereas copal easily liquifies,<br />
burns with much smoke, and decrepitates more than<br />
amber.<br />
Amber is likewise adulterated by gum arabic, gum thus,<br />
shellac, and glass pastes. The last can easily be distin-<br />
guished by their hardness, and the others by their solubility<br />
in hot water.<br />
Amber very frequently has inclosed within it insects,<br />
such as flies, beetles, &c., in a state of complete preservation.<br />
Such specimens are much sought for, and command<br />
a very high piice ;<br />
and on that account the adulterations<br />
are mostly practised, and in the following manner : either<br />
by boring a hole in the amber, introducing the beetle,<br />
filling<br />
it up with pulverized gum-mastic, and then let-<br />
ting it melt over a charcoal fire ;*or by melting the amber,<br />
throwing in the insects, and letting it cool. The former<br />
adulteration may easily be detected, since the mastic will<br />
never be able to combine closely with the amber, and shows<br />
more or less cracks and fissures ; but the latter is scarcely<br />
to be detected, without a scientific investigation of the in-<br />
closed insects, which in the natural specimens do not exist<br />
in the present world, being called antediluvian, or extinct<br />
species of animals.<br />
The most extensive use of this elegant material is for the<br />
manufacture of the mouth-piece, an essential constituent ol
350 A POPULAR TREATISE ON GEMS.<br />
Amber mouth<br />
the genuine Meerschaum and Turkish pipe.<br />
pieces have always been in great request in the East, where<br />
but in the United States a fash-<br />
they command great prices ;<br />
ionable taste, similar to other countries, has sprung up of<br />
late, which bids fair to outvie the East. No young man of<br />
any pretensions to smoking cigars, can do so without his<br />
meerschaum and amber cigar-holder. The dearer he pays<br />
for this luxury, the more respected he considers himself.<br />
There is a current belief in Turkey, that amber is incapable<br />
of transmitting infection, and as it is a great mark of<br />
politeness to offer the pipe to a stranger, this supposed<br />
negative property of amber accounts, in some measure, for<br />
the estimation in which it is held.<br />
There is evidence of the extreme antiquity of amber in<br />
the fact that the Phoenicians imported it from Prussia.<br />
Since that period it has been obtained there uninterruptedly,<br />
and no diminution in the quantity annually collected has<br />
been perceived. If we incline to the theory that amber is<br />
a species of wax or fat, having undergone a slow process<br />
of putrefaction, based on the fact that chemists are able to<br />
convert ceraceous or fatty substances into succinic acid, by<br />
inducing oxidation artificially, the belief must be entertained<br />
that a new formation of amber is constantly going<br />
on, which theory is strengthened by the different appearance<br />
of the varieties of amber, which seem to exhibit the<br />
successive stages of its development and decay. On the<br />
other hand, Tacitus, in his Germania, states that it is a resin,<br />
exuded by certain conifers, traces of which are frequently<br />
observed among the amber. Certain it is that, at one<br />
time, amber must have been liquid, from the simple fact<br />
that numerous small animals are found inclosed within it ;<br />
these, for the most part, are insects belonging to an extinct<br />
species of arachnidse. A specimen containing the leg of<br />
a toad was seen among an extensive collection at the Lon-
AMBER. 351<br />
don Exhibition, and it is said that in China, amber contain-<br />
ing insects is of frequent occurrence. From the fact that<br />
amber and fossil wood have been found in alluvial deposits<br />
of sand and clay, and associated with ocean shale and iron<br />
pyrites, at a depth of sixty feet, it is the author's firm belief<br />
that the marine amber is a subsequent formation to the<br />
terrestrial amber. That Pliny already took it for a vege-<br />
table production, may be inferred from his :<br />
expression<br />
"<br />
quod arboris succura, prisci nostri credidere."<br />
The different kinds of amber are distinguished by varie-<br />
ties of color and degrees of transparency. All shades of<br />
yellow, from the palest primrose to the deepest orange, or<br />
even brown, are its constant colors. In point of clearness,<br />
amber varies from vitreous transparency to perfect opacity;<br />
some are nearly as white as ivory, which is, however, a rare<br />
occurrence. If there are two layers together, the trans-<br />
parent and opaque varieties, it is used for cutting cameos.<br />
An inquiry naturally suggests itself as to which of these<br />
varieties of amber is the most valuable. It is self-evident<br />
that this must depend, as in the diamond, upon the size and<br />
the uniformity of the pieces. Besides, as all varieties ex-<br />
cepting the white, which has its special uses, are equally<br />
applicable for manufacturing purposes, it follows that the<br />
value of any particular sort must depend in a great measure<br />
upon its variety. The straw-yellow, slightly translucent<br />
variety is the most rare, and is that which the Orientals<br />
prefer to all others, and which they purchase at extrava-<br />
gant prices. Every piece of that quality is exported to<br />
Turkey, in the raw or manufactured state.<br />
Among the exquisite specimens of amber in the London<br />
Crystal Palace, were four most splendid imaums, or round<br />
amber mouth-pieces, richly ornamented with brilliants the<br />
;<br />
shortest two, which in smoking are pressed against the<br />
lips, were each worth three hundred pounds sterling, and
352 A POPULAR TREATISE ON GEMS.<br />
were each of that peculiar color and degree of transparency<br />
which approaches nearest to the Turkish ideal of beauty.<br />
The two longer mouth-pieces were of a different form, and<br />
although not of so good a color, nor enriched with as many<br />
diamonds, were still valued at two hundred pounds sterling<br />
each.<br />
A large specimen obtained from the amber pits in Prus-<br />
sia, weighing six pounds,<br />
and another marine amBer and<br />
waterworn, weighing four and a half pounds, owned by Mr.<br />
Wolff Manheimer, of Konigsberg, Prussia, were likewise<br />
at the London Exhibition.<br />
At the Royal Museum in Berlin, is a large mass of amber,<br />
weighing eighteen pounds.<br />
In the kingdom of Ava, a mass nearly as large as a<br />
child's head was found some years ago, which was inter-<br />
sected in various directions by veins of crystallized carbon-<br />
ate of lime.<br />
Amber is very fusible and liable to be broken. To join<br />
the broken pieces, and to unite them in such a manner as<br />
to look and wear as well as new, the author of this treatise<br />
recommends the use of soluble glass (either the silicate of<br />
soda, or silicate of potash), which is applied to the fissure<br />
or fractured part, after which the united parts are tied with<br />
with a twine and kept so for some days ; it will then remain<br />
firm. Thick shellac varnish is also highly recommended :<br />
dissolve bleached shellac in ninety-five per cent, alcohol,<br />
to the consistency of syrup, touch the broken parts with<br />
the varnish, tie them with twine, and leave the article in<br />
a warm place for some days before using.<br />
Amber powder made into a paste with thick shellac<br />
varnish and moulded, may easily be made into a variety of<br />
forms, and represent genuine amber.<br />
The most extraordinary collection of specimens of amber<br />
may be seen in the cabinet at Dantzic. A specimen of
JET. 353<br />
amber of fifteen pounds weight is preserved in the cabinet<br />
at Berlin. The inhabitants of Colberg, in 1576, presented<br />
to the Emperor Rudolph II. a specimen weighing eleven<br />
pounds.<br />
JET.<br />
This mineral occurs massive ;<br />
has a conchoidal fracture ;<br />
is opaque; has a shining lustre; and is of a jet, or pitch-<br />
black color. It is pretty soft, and yields to the knife ;<br />
its hardness is 1* to 2*5; specific gravity, 1*29 to 1*35;<br />
it burns with a greenish flame, and emits a strong bitumin-<br />
ous smell. In trade it is also called black amber, or pitch<br />
coal. It is found in the brown-coal formation, the plas-<br />
tic clay, and the lias, with lignite and amber, in England,<br />
France, Silesia, Hesse, Italy, Spain, and Prussia.<br />
Jet bears a high polish, and is wrought into necklaces,<br />
ear-rings, crosses, rosaries, snuff-boxes, buttons, bracelets,<br />
and particularly mourning jewelry. It is at first generally<br />
assorted to select the best pieces, most suitable for working ;<br />
such as are free from iron pyrites, lignite, and have no<br />
cracks or fissures. It is then turned on a lathe, and like-<br />
wise on horizontal sandstone wheels, which run unequally<br />
on their periphery, by which the various specimens may be<br />
cut and polished at the same time. During the operation<br />
the jet must be moistened with water, else it may crack<br />
from being overheated. It is polished with rotten-stone or<br />
crocus martis and oil, on linen or buckskin ; and lastly by<br />
the palm of the hand.<br />
The manufacturing of jet ornaments was formerly a con-<br />
siderable branch of industry in France, where, in 1786, the<br />
department de PAube occupied twelve hundred workmen ;<br />
but at the present time it is not worn, and the black enamel<br />
is substituted for it.<br />
Jet is a species of bituminous coal, which has several
354 A POPULAR TREATISE ON GEMS.<br />
names, such as common coal, black coal, cherry coal, splint<br />
coal, cannel coal, jet, lignite, &c.; more properly, how-<br />
ever, it is a variety of cannel coal, but it is much blacker,<br />
and has a more brilliant lustre. It occurs in detached<br />
pieces, in clay, on the coast near Whitby, in Yorkshire,<br />
and is the gagates of Dioscorides and Pliny, a name de-<br />
rived from the river Gagas, in Syria, near the mouth of<br />
which it was found.<br />
Cannel coal, which comes nearest to jet, has a dark-<br />
grayish, black, or brownish-black color, a large<br />
conchoid al<br />
fracture, and receives a good polish ; takes fire readily, and<br />
bums without melting, with a clear yellow flame. On this<br />
account it has been used as a substitute for candles, and<br />
hence receives its name. It is very abundant in Scotland,<br />
and in several parts of Ayrshire ; is wrought into inkstands,<br />
snuff-boxes, and other similar articles. In England the<br />
bituminous coal trade is a large traffic ; over one hundred<br />
thousand people are engaged in Newcastle, in digging.<br />
The principal coal mines of France are those of St. Etienne,<br />
Mons, Charleroi, and Liege. Germany has some coal ; but<br />
Belgium, Norway, Denmark, and Russia seem to be entirely<br />
destitute of coal beds. Some few beds are found in the<br />
Apennines, in Italy. In Spain, coal occurs in Andalusia,<br />
Aragon, Estremadura, Catalonia, Castile, and the Asturias,<br />
but not in large quantities. The only coal bed in Portugal<br />
which is worked, is situated in the province of Beira.<br />
Coal is also abundant in China, Japan, the island of Madagascar,<br />
Africa, and New Holland. But nowhere are its<br />
deposits more extensive and numerous than in the United<br />
States. It occurs extensively throughout the Middle and<br />
Western States. The great coal formation in the United<br />
States is one of its principal and most striking geological<br />
features, and in its influence upon our industrial pursuits,<br />
it is unquestionably the most important of all. The coal
JET. 355<br />
measures are distributed over two principal areas, termed<br />
the gre%t eastern and the great western coal fields, being<br />
separated from each other by a wide area of older formations.<br />
The eastern, or Alleghany coal field, may be traced<br />
from near the northern limit of Pennsylvania to the south-<br />
west, in a line parallel with the Alleghany chain, quite to<br />
the central part of the State of Alabama. The anthracite<br />
basins, which are of comparatively small extent, lie beyond,<br />
or to the east of the line here traced as the limits of the<br />
great eastern coal field.<br />
From its northeasterly margin it is traced along a veiy<br />
irregular outline, as far as the Alleghany river, in Warren<br />
county, Pennsylvania,<br />
and from thence it follows a direction<br />
nearly parallel to the shore of Lake Erie, to Portage and<br />
Summit counties, in the State of Ohio. From thence it<br />
follows a line generally parallel to its eastern margin, though<br />
gradually converging to its southern extremity, in Alabama.<br />
Tli is coal field has a length of more than seven hundred<br />
and fifty miles, and an extreme breadth of one hundred<br />
and eighty miles. The superficial area has been estimated<br />
by Richard C. Taylor to be sixty-five thousand square<br />
miles and when we consider the ;<br />
aggregate thickness of<br />
the different beds of coal over this wide extent, the ag-<br />
gregate amount of fossil fuel appears indeed incomprehensible.<br />
The great western coal field, or, as it has been usually<br />
termed, the Illinois coal field, occupies the larger part of<br />
the State of Illinois, and parts of Indiana and Kentucky.<br />
It is separated only by a narrow belt of the lower forma-<br />
tions, along the Mississippi valley, from the coal fields of Iowa<br />
and Missouri, the extent of which has lately been shown<br />
to be much greater than had been supposed. Including<br />
the parts of this field on both sides of the Mississippi river,<br />
its greatest extent from southeast to northwest, or from
356 A POPULAR TREATISE ON GEMS.<br />
the headwaters of Green river, in Kentucky, to its northern<br />
limit, on the Desmoines river, in Iowa, is more than five<br />
hundred miles ; while its greatest breadth across the States<br />
of Indiana, Illinois, and Missouri, is more than four hun-<br />
dred miles, and from its northern termination in Iowa to<br />
its present known limits, on the Osage river, at the south,<br />
is more than three hundred miles. This western coal field,<br />
therefore, including the area thus occupied on both sides of<br />
the Mississippi river, has a much greater superficial extent<br />
than the eastern coal field, already described. Perhaps<br />
the entire area may be estimated at one and a half that of<br />
the Alleghany coal field, or nearly one hundred thousand<br />
square miles. Still farther to the south, in Arkansas, there<br />
is a coal field of considerable extent, which has not yet<br />
been fully explored ; it is probably connected with the<br />
Missouri field.<br />
There are coal fields in Michigan, Rhode Island, and<br />
Massachusetts, Eastern Virginia, North Carolina, near Fort<br />
Laramie, Puget's Sound, and Bellingham Bay.<br />
The entire area occupied by coal measures in the United<br />
States, east of the Rocky Mountains, is about two hundred<br />
thousand square miles.<br />
The quantity of bituminous and anthracite coal consumed<br />
in the United States, may be estimated at fifteen millions<br />
of tons annually.<br />
The jet of Whitby, in Scotland, forms part of a thick<br />
bed of lignite found there in the upper lias marls ; it differs<br />
in this respect from the jet worked in France and Spain,<br />
which is found in irregular veins in the lower marls of the<br />
cretaceous series.<br />
Cannel coal is chiefly used in the manufacture of gas,<br />
but some of the harder and more compact kinds are oc-<br />
casionally cut into various ornamental objects, several of<br />
which were represented in the London Exhibition ; the most
MEERSCHAUM. 357<br />
interesting of these, as a finished work, well designed and<br />
well executed, was a garden seat, from the parrot coal, in<br />
the Fifeshire coal field, exhibited by His Royal Highness,<br />
Prince Albert ; also a model of the Durham Monument,<br />
and a wine-cooler, both of which were wrought from the<br />
Newcastle coal field. A set of chessmen and a snuff-box,<br />
both made of cannel coal from China, were exhibited. In<br />
Roman Catholic countries, a large quantity of small orna-<br />
ments, such as crosses, beads, rosaries,
358 A POPULAR TREATISE ON GEMS.<br />
cobalt becomes red, and is decomposed by hydrochloric<br />
acid.<br />
It is found in nodules, at Kiltschiek, near Conian, in Na-<br />
tolia, in a large fissure, six feet wide, in calcareous earth ;<br />
near Thebes, and in many other parts of Greece ; Vallecas,<br />
near Madrid, and Cavaiias, near Toledo ; Pinheiro, in Por-<br />
Hrubschitz and Osbowern, in Moravia, and in Swe-<br />
tugal ;<br />
den ; but by far the largest quantity is derived from the<br />
peninsula of Natolia,<br />
in Asia Minor. It is called meer-<br />
schaum, or ecume de mer, on account of the belief of the<br />
workmen engaged in digging the mineral, that it grows<br />
again in the fissures of the rock, and that it puffs itself up<br />
like froth. Good meerschaum is tolerably soft ; resists the<br />
pressure of the hand, but is easily indented by the finger<br />
nail, and especially after having been wetted ; it may be<br />
easily cut with a knife.<br />
Although the fracture is earthy, and rarely conchoidal,<br />
still the state of aggregation of pure meerschaum is very<br />
variable, as is proved by the marked difference in the specific<br />
gravity. Some kinds sink in water, others float on<br />
its surface ;<br />
and these qualities are, in the estimation of the<br />
pipe-maker, indicative of different values, for he rejects<br />
both the very heavy and the very light, and prefers those<br />
of medium density. The light varieties are generally very<br />
porous, and even contain large cavities, whilst the heavier<br />
kinds are suspected to be an artificial product. Formerly,<br />
the material was roughly fashioned, on the spot, into bowls,<br />
which were elegantly carved in Europe. The art was specially<br />
cultivated at Pesth and Vienna, where it formed an<br />
extensive and important branch of trade. These rough<br />
bowls still occur in commerce ; but by far the greater part<br />
of the meerschaum is exported in the shape of irregular<br />
blocks, with obtuse angles and edges, requiring careful<br />
manipulation, with the aid of water, in order to remove
MEERSCHAUM. 359<br />
irregularities and faulty portions. This preliminary treatment<br />
still leaves numerous blemishes. The meerschaum of<br />
commerce has defects of various kinds ; besides various<br />
minerals scattered through its mass, it contains a hard sort<br />
of meerschaum, which the manufacturers call chalk, and<br />
which is the cause of much difficulty in the carving. Pre-<br />
vious to the mechanical treatment of the meerschaum for<br />
making the bowl, it is subjected to a certain preparation.<br />
It is soaked in a liquified unguent, composed of wax, oil,<br />
and fat ;<br />
the wax and the fat which the substance absorbs,<br />
cause the colors which meerschaum assumes after smoking.<br />
Under the influence of the heat produced by the burning<br />
tobacco, the wax and fat pass through all the stages of a<br />
true process of dry distillation ; the substances thus formed<br />
become associated with the products of the distillation of<br />
the tobacco, and by their diffusion through the meerschaum,<br />
all those gradations of color which are so highly prized by<br />
the connoisseur, are produced.<br />
Occasionally, though rarely, the bowls are artificially<br />
stained, by steeping them, before they are soaked in wax,<br />
in a solution of copperas, either alone or with dragon's<br />
blood. This process must manifestly very materially affect<br />
the shade of color produced in smoking.<br />
The large quantity of meerschaum parings left in roughing<br />
out the bowls, would entail considerable loss, unless<br />
some process had been devised of rendering them available.<br />
A species of meerschaum bowl has long been known in<br />
commerce, under the name of massa bowls, which is made<br />
from the parings. They are triturated to a fine powder,<br />
boiled in water, and moulded into blocks, with or without<br />
the addition of clay. Each of these blocks suffices for one<br />
but before they can be used, they must be allowed<br />
bowl ;<br />
to dry for some time, as they contract considerably. These<br />
bowls are distinguished from real meerschaum by their
360 A POPULAR TREATISE ON GEMS.<br />
greater specific gravity ; but there is no very certain test by<br />
which the real meerschaum can be distinguished from the<br />
composition, and many suppose that all the heavier descriptions<br />
are spurious, though there is no absolute proof of<br />
this being the case. A negative test may, however, be<br />
mentioned : the composition bowls never exhibit those little<br />
blemishes which result from the presence of foreign bodies<br />
in the natural meerschaum ; therefore, if a blemish occur<br />
in a meerschaum bowl (which is frequently the case), the<br />
genuineness of the bowl is rendered more probable ;<br />
but as<br />
these do not show until after the bowl has been used for<br />
some time, the test is not of much value.<br />
Very extensive and valuable collections of meerschaum<br />
pipes and mouth-pieces were exhibited in the London Crystal<br />
Palace, from Gotha, of both real and imitation meer-<br />
schaum bowls. From Turin, Sardinia, were elaboratelycarved<br />
meerschaum pipe-bowls, the sculpturing of which<br />
was very exquisite. From Austria a large collection of<br />
massa pipe-bowls and cigar-tubes, which were manufactured<br />
from meerschaum dust ; the former of these articles was<br />
elegant, and the execution so good, that they were with<br />
difficulty distinguished from the real meerschaum.<br />
The importation of meerschaum pipes and cigar-tubes<br />
into the United States has of late become very extensive,<br />
and it was estimated at two hundred thousand dollars the<br />
last year.<br />
LAVA.<br />
This mineral is a compound of several minerals, and is a<br />
volcanic production. It occurs massive, with vesicular or<br />
porous marks ; has a splintery and conchoidal fracture ; a<br />
lustre dull or glistening ; is opaque, and of gray, brown,<br />
red, yellow, black, green, and white colors, of all their<br />
shades. It often contains crystals of felspar, leucite,
JADE. 361<br />
hornblende, &c. In the arts, for ornamental purposes, the<br />
compact varieties, only, are cut and polished.<br />
In Naples,<br />
jewelry and ornaments in great quantities are manufactured<br />
and exported ;<br />
such as pins, ear-rings, intaglios, snuff-boxes,'<br />
vases, candelabras, &c. The different lavas are cut with<br />
sand and emery, and polished with pumice-stone. Lava is<br />
found in all volcanic countries, and particularly at Etna,<br />
Vesuvius, Hecla, in Mexico, the Lipari Islands,
362 A POPULAR TEEATISE ON. GEMS.<br />
SERPENTINE.<br />
This mineral derives its name from its variegated color,<br />
which resembles the skin of a serpent. It is generally<br />
divided into two varieties :<br />
tine ;<br />
the common, or opaque serpen-<br />
and the precious, noble, or tmnslucent serpentine.<br />
Serpentine occurs massive ; the common is occasionally<br />
crystallized in rhomboidal crystals,<br />
in Norway, New Jer-<br />
it has a splintery, uneven, and con-<br />
sey, and Pennsylvania ;<br />
choidal fracture ; is unctuous to the touch ; yields to the<br />
knife ; its colors are green in all its shades, but also reddish<br />
and grayish ; hardness, 3 '4 ; specific gravity, 2*5 ; is infusi-<br />
ble before the blowpipe, but with borax dissolves into a<br />
transparent glass.<br />
It does not belong to the stratified<br />
rocks, but to the ophites of Brogniart, and is mostly asso-<br />
ciated with granite, gneiss ; micaceous, chlorite, argillaceous<br />
schists, and limestone; it therefore belongs to the primi-<br />
tive formation.<br />
Serpentine, for richness and variety of colors, exceeds all<br />
other rocks ; and it abounds all over the globe, in large<br />
consolidated masses. The finest precious serpentines come<br />
from Fahleen and Gulsjo, in Sweden, the Isle of Man, the<br />
neighborhood of Portsay, in Aberdeenshire, Corsica, Sibe-<br />
ria, and Saxony. Common serpentine occurs at Lizzard<br />
Point, in Cornwall. In the Alps we find the serpentine<br />
nine thousand feet high ; in France, the mountains of Li-<br />
mousin ;<br />
in Spain, Norway, Sweden, Scotland, the Shetland<br />
Isles, England, Italy, Bohemia, Saxony, Bavaria, and Swit-<br />
zerland; in the United States we find it all along the<br />
Atlantic coast, where the primary rocks are found, as at<br />
Hoboken (New Jersey), opposite to New York city, War-<br />
wick (New Jersey), as far as Maryland, at Bare Hills,<br />
through Pennsylvania, Rhode Island, Connecticut, Massa-<br />
chusetts, Vermont, &c. The serpentine beds of Massachu-
SEKPENTTXE. 363<br />
setts are inexhaustible. In Middlefield, Massachusetts, the<br />
bed is one quarter of a mile in breadth and six miles in<br />
length, which alone would be sufficient to supply the whole<br />
world with a valuable material for ornamental and archi-<br />
tectural purposes. There are beds at Westfield, Blanford,<br />
Pelham, Zoar, Windsor, Marlborough, Cavendish, and<br />
other towns in Vermont. Most beautiful specimens are<br />
and latterly a new<br />
found in Newbury, near Newburyport ;<br />
locality was discovered by Dr. Jackson, in Lynufield,<br />
Massachusetts.<br />
Serpentine<br />
incloses chromate of iron in the Shetland<br />
Islands, Maryland, &c. ; and is on that account of the<br />
highest importance to the artist.<br />
It is easily wrought on lathes into various articles ; such as<br />
snuff-boxes, vases, inkstands, &c. ; in a small place named<br />
Zoblitz, in Saxony, several hundred persons are constantly<br />
employed in the manufacture of boxes, trinkets, and chim-<br />
ney-pieces. The locality at Granada, in Spain, has supplied<br />
many churches and palaces of Madrid with large columns,<br />
and other ornaments. It is* really surprising that the in-<br />
habitants of those districts where the precious serpentine<br />
is found, have not yet employed it as an article of trade, as<br />
the quality of the American serpentine is, if not superior<br />
to the English and Spanish, certainly not inferior to any<br />
hitherto found : and I trust that the day is not far distant<br />
when our parlors will be embellished with mantel-pieces,<br />
tables, and mantel-ornaments, made of it. Candlesticks,<br />
mugs, pitchers, knife-handles, fire-iron-stands, jamb-hooks,<br />
and many other domestic articles, might be formed of it,<br />
instead of silver-plated, steel, and cast-iron ware.<br />
Serpentine<br />
is often associated with a number of other<br />
minerals : as, , serpentine with talc ; 5, serpentine with<br />
diallage or schiller-spar ; c, serpentine with amianthus ; d,<br />
serpentine with asbestos ; e^ serpentine with garnets ; /,
364 A POPULAR TREATISE ON GEMS.<br />
%<br />
serpentine with actinolite, &G. That variety which contains<br />
amianthus in a layer, is sometimes exceedingly beautiful ;<br />
and when polished has the appearance of satin spar.<br />
MARBLE.<br />
This is a carbonate of lime, and a wide range of minerals<br />
belong to this class, containing<br />
substances which are sub-<br />
servient to architectural and ornamental purposes ; the<br />
author intends, therefore, treating this subject more exten-<br />
than other common<br />
sively and giving it a wider range<br />
minerals, and to copy from the jury report of the London<br />
and New York Exhibitions.<br />
The primary form of calcareous spar is an obtuse rhom-<br />
bohedron, with a great many secondary forms; has a<br />
hardness of 2'5 to 3'5 ; specific gravity, 2'5 to 2*7 ; it has<br />
a vitreous lustre, also earthy; white or grayish-white<br />
color usually white, with a great variety of shades<br />
streak ;<br />
of gray, red, green, and yellow, also brown and black ; it<br />
is transparent and opaque, the transparent varieties ex-<br />
hibit double refraction very distinctly ; fracture usually<br />
conchoidal, but obtained with difficulty, when the specimen<br />
is crystalline. It is composed of .lime and carbonic acid,<br />
the colored varieties often contain, in addition, small portions<br />
of iron, silica, magnesia, alumina, and bitumen, and<br />
acids produce a brisk effervescence ; before the blowpipe<br />
it is infusible, it loses, however, its carbonic acid, gives out<br />
an intense light, and ultimately is reduced to pure lime,<br />
or quicklime.<br />
Calcareous spar appears under a very great variety of<br />
forms and aspects ;<br />
been created by mineralogists.<br />
a great many species have, therefore,<br />
Iceland spar was first applied to a transparent crystal*<br />
lized variety from Iceland, where it was found in a cavity
MARBLE. 365<br />
in trap, with stilbite, on the north shore of Eskifiord, on<br />
the east coast of Iceland ; and the property of double re-<br />
fraction was first observed in this variety of carbonate of<br />
lime.<br />
Oolite consists of minute spherical particles aggregated<br />
by calcareous cement, so as to produce a massive structure<br />
and nearly earthy appearance ; it occurs in extensive beds,<br />
and is so called from its resemblance to the roe of fish,<br />
from wov, the egg.<br />
Pisolite, or pea-stone, differs from oolite in the larger<br />
size of its particles, which are composed of concentric la-<br />
mina.<br />
Chalk is a massive opaque variety, usually white, and<br />
possessing a purely earthy aspect and absence of lustre, it<br />
is usually much softer than the other varieties of this<br />
species, and appears to consist in a great<br />
aggregation of fossils, chiefly infusorial.<br />
measure of an<br />
Tufa, an alluvial deposit from calcareous springs; it<br />
has a very porous structure.<br />
Agaric mineral, or rock milk, is a loose friable variety,<br />
deposited from waters containing carbonate of lime in so-<br />
lution, it is formed about lakes whose waters are impregnated<br />
with lime ; also in fissures in limestone, and in lime-<br />
stone caverns.<br />
Anthraconite, or stink-stone, swine-stone, which is found<br />
columnar, granular, and compact, of various shades, emits<br />
a fetid odor when struck with the hammer.<br />
Stalactites are pendant masses of limestone, formed in<br />
limestone caverns by the percolation of Water, holding<br />
lime in solution, through their rocky roofs ; the evaporation<br />
of the water causes the deposition of the lime, and thus, in<br />
time, columns are often formed extending from the roof to<br />
the floor of a cavern ; the water which drops to the floor<br />
from the roof also evaporates and causes the formation of a
366 A POPULAR TREATISE ON GEMS.<br />
layer of limestone over the floor ; this variety<br />
has been<br />
called stalagmite.<br />
Argentine possesses a silvery-white lustre and contains a<br />
little silica.<br />
Fontainebleau limestone Is an aggregate of secondary<br />
rhombohedrons, containing, mechanically mingled, large<br />
portions of sand ;<br />
this species in some of its forms is very<br />
generally diffused.<br />
Marble includes all the imperfectly crystalline and earthy<br />
varieties which admit of a high polish ; it is also called<br />
granular limestone, or statuary marble, which forms sometimes<br />
entire mountains ; but more frequently occurs in beds<br />
in gneiss, porphyry, and mica slate. The world has been<br />
supplied for centuries past with statuary marble from the<br />
Carrara beds on the gulf of Genoa, from the islands of<br />
Paras, Naxos, and Tenos ;<br />
Pentillicus and Hymettus, near<br />
Athens, in Greece, and Schlandens, in Tyrol.<br />
Calcareous spar is the principal source of our polished<br />
marbles, the material for sculpture, quicklime, for artificial<br />
stone, flux for smelting ores, &c. A peculiarly fine-grained<br />
compact variety is employed in lithography, which is mostly<br />
imported from Bavaria, under the name of lithographic<br />
stone..<br />
where the manufac-<br />
Italy is pre-eminently the country<br />
ture of marble has been found most congenial to the<br />
artistic feeling of the mass of the people, and there, or in<br />
its vicinity, at the present day, a large part of the best<br />
marbles used in central Europe are obtained and worked.<br />
Of late years, however, France, Spain, Portugal, and parts<br />
of Germany and Belgium, have employed for their own use<br />
and in their own style, many useful and valuable marbles<br />
with which they abound, and in England manufactories<br />
have arisen, at first and chiefly in Derbyshire, but also in<br />
Devonshire and Cornwall, in which much has been done to
MARBLE. 367<br />
raise the character of marble decoration, by employing the<br />
excellent material which abounds in those places, and by<br />
introducing various useful objects of house-decoration at a<br />
price which, though somewhat too High for the mass of<br />
consumers, is far below that of foreign goods of the same<br />
kind in that country. Ireland, also, in which several fine<br />
marbles occur, has given proof of some activity in this<br />
manufacture, for which, indeed, nature has afforded many<br />
facilities to carry out to full advantage.<br />
Many marbles from Greece, Italy, and the coast of Asia<br />
Minor, were used Jby the ancients, but the quarries are now<br />
exhausted or concealed by rubbish. Among them may be<br />
mentioned the true Parian of Greek sculptors, and some<br />
other fine white marbles the nero ;<br />
antico, now a very rare<br />
black marble, considered purer and better than the known<br />
kinds ; the rosso antico, a deep blood-red marble with veins<br />
and spots; the verde antico, a green and very beautiful<br />
porphyritic breccia ; the giallo antico, not unlike the modern<br />
Sienna marble, of very rich yellow tint, with some others.<br />
Most of these are only known in sculptured specimens ; but<br />
many, if not all the colors are closely approximated by<br />
recent marbles.<br />
The French marbles, those illustrating the Pyrenees and<br />
Vosges, were not less interesting. Messrs. Derville exhibited<br />
one hundred slabs of marble, each sixteen inches in<br />
height, comprising twenty varieties, and among them the<br />
marble called " girotte" (spotted with red and brown), and<br />
the -white marble of St. Beat, all remarkable for the rarity<br />
of their colors and the beauty of their polish. The Campan<br />
marbles also possess a peculiar geological interest in the<br />
number of goniatites which they inclose and which are<br />
often mixed confusedly with the paste; an arrangement<br />
which evidences the great change which these limestones<br />
have undergone at some period, and which proves their
368 A POPULAR TREATISE ON GEMS.<br />
metamorphism, like the limestones of the State of New<br />
York.<br />
The chief marble manufacture of England is in a part of<br />
Derbyshire remarkable for its picturesque beauty, extend-<br />
ing along the valley of the Derwent and its principal<br />
tributary, the Wye, from below Buxton to Derby.<br />
The machinery for sawing and polishing was first estab-<br />
lished at Derbyshire at the village of Ashford, near Bake-<br />
well, in the year 1748, water being the motive power; in<br />
1810, similar machinery was erected in Bakewell, and for<br />
many years past, also, in Derby.<br />
The most important marbles of Derbyshire are the black,<br />
the rosewood, the encrinital, the russet or bird's eye, and a<br />
mottled dark and light gray kind, occasionally containing<br />
numerous small corals. Of some of these there are several<br />
varieties. Others might be added to the list of those<br />
found in the northern part of the county, one of which<br />
is a beautiful red, resembling the rosso antico, but it is ob-<br />
tained only in small blocks or lumps.<br />
. At Welton, in Staffordshire, near the borders of Derby-<br />
shire, are marbles differing much from the above, but they<br />
have not been brought into any considerable use, and are<br />
generally subject to flaws. The black marble is of very<br />
fine color and texture, but large slabs free from small veins<br />
of calcareous spar are rare ;<br />
the best quality occurs in beds<br />
of from three to eight inches in thickness, some beds are<br />
thicker. This marble is, perhaps, superior to the similar<br />
kinds found in other parts of Europe and is greatly valued<br />
for inlaying ; it is tough and contains a good deal of carbon,<br />
which imparts the color.<br />
Black marble is extensively used for ornamental objects,<br />
such as vases, pedestals, chimney-pieces, &c., for which it<br />
is admirably adapted.<br />
Rosewood marble is extremely hard and of close texture ;
MARBLE. 369<br />
the beds are of considerable thickness, but the most beau-<br />
the<br />
tiful part of the ma'rble ia only about six inches thick ;<br />
name is derived from the marking of the marble being<br />
somewhat similar to that of rosewood.<br />
Encrinital marble is the one in most extensive use, and<br />
contains very numerous fossils, consisting almost exclusively<br />
of the broken fragments of encrinital stems, often entangled<br />
in coral ; it may be obtained in blocks of large superfices<br />
and of a thickness of two to two and a half feet.<br />
Russet, or bird's eye, takes its name from its color and<br />
the shades varying from light-gray to brown.<br />
appearance ;<br />
It contains numerous minute fossils, also encrinital, and is<br />
found in beds from six to eighteen inches in thickness.<br />
Dark and light mottled gray marble, called Newburgh<br />
marble, and the overlying bed, which is coralline, can be<br />
obtained from one to two feet thick.<br />
The manufacture of Devonshire marble is much more<br />
modern, and the material is generally less manageable.<br />
Almost all the beautiful marbles of that county, especially<br />
those near Plymouth, are fossiliferous, brittle, and very apt<br />
to contain veins and cracks. The marbles of Devonshire<br />
belong to an older geological period than those of Derbyshire,<br />
the latter being exclusively of the carboniferous<br />
limestone series, underlying the coal measures and mill-<br />
stone grit ;<br />
while the former are of the devonian or middle<br />
paleozoic epoch.<br />
Among the most notable marbles in the London Exhibi-<br />
tion, may be mentioned the following articles::<br />
Three chimney-pieces of Carrara marble, with many<br />
sculptured figures, from Milan, in Italy ^ columns and<br />
pedestals of the madrepore marble, from a quarry in Devon-<br />
shire ; some pedestals of green marble, from Connemara,<br />
in Ireland ; a table belonging to the East India Company<br />
was exhibited, the top of which consists of a slice of a
370 A POPULAR TREATISE ON GEMS.<br />
column from Nineveh;<br />
several slabs of the Lumachella<br />
marble, and a marble called verde di prato, were exhibited<br />
from Tuscany, which were extremely beautiful. A bust of<br />
Grattan, of Irish marble of a beautiful yellow color, attracted<br />
much attention.<br />
It may not be out of place to mention here the extensive<br />
display of marble statuary, which was also at the London<br />
Exhibition, only a few will be enumerated for want of<br />
space :<br />
1. Marble statue representing Gratitude.<br />
2. Group representing Eve with Cain and Abel asleep in<br />
her arms.<br />
3. Marble statue of Susannah.<br />
4. Iconic. statue in marble.<br />
5. Marble statue of Eve after the Fall. ^ .<br />
6. Marble statue representing the Greek Slave.<br />
7. Marble group representing Cephalus and Procris.<br />
8. Marble figure representing a Boy frightened by a<br />
Lizard.<br />
9. Reclining figure, in marble, representing Ishmael.<br />
10. Marble statue of a Boy catching a Butterfly; also,<br />
a marble figure representing Arethusa.<br />
11. Marble statue representing Giotto.<br />
12. Marble statue of the sculptor Flaxman, and two<br />
statues of the first Lord Eldon, and his brother, Lord<br />
Stowell.<br />
13. Marble group of a Girl with a Lamb, representing<br />
Innocence.<br />
14. Marble statue representing a Startled Nymph.<br />
15. Marble figure of a Bacchante.<br />
16. Marble statue of Dying Gladiator.<br />
17. Marble group representing an episode in the history<br />
of the war between the Amazons and the Argonauts.<br />
18. Marble statue of Psyche. %
MAKBLE. 371<br />
19. Marble statue representing a Girl carrying a Nest of<br />
Cupids.<br />
20. Marble statue representing Eurydice.<br />
21. Marble group, "The Orphans."<br />
22. A reclining marble figure of Bacchus.<br />
23. Model in marble of a Friar presenting the Crucifix<br />
to two Children.<br />
24. Marble bust of the poet, Vincenzo Monti.<br />
25. Figure in marble representing Mary Magdalen.<br />
26. Marble group, Sleeping Child and Dog.<br />
Italian marble furnished the material from which most<br />
of the above sculptures were wrought.<br />
The United States limestones, for building purposes, and<br />
marble for statuary, are found in great abundance, and<br />
many of them fairly compare with the Italian and English<br />
marbles. The white granular limestones are mined in many<br />
places ; they all belong to the newer metamorphic rocks,<br />
where they occupy a wide range, from Vermont, Massa-<br />
chusetts, Rhode Island, Connecticut, New York, Pennsyl-<br />
vania, and Maryland, to Missouri ; but the best statuary<br />
marble has as yet only been found in the eastern part<br />
of Vermont: 100,000 cubic feet of good marble, suitable<br />
for building stone, mantel-pieces,
372 A POPULAR TREATISE ON GEMS.<br />
ries in Massachusetts are at West Stockbridge, Egremont<br />
Groat Harrington, Lanesborough, New Ashford, Sheffield,<br />
and New Marlborongh. In New York, marble is quarried<br />
in large quantities at Hastings and Sing Sing, and Dover,<br />
in Dutchess county, and the range of granular limestones<br />
extends through Columbia, Dutchess, and Putnam coun-<br />
ties ;<br />
and in Connecticut the same granular limestones occur<br />
in abundance; also in New Jersey, a few miles west of<br />
Philadelphia, and near Ilagerstown, in Maryland. The<br />
marble quarries in Rhode Island, Eastern Massachusetts,<br />
and Maine, furnish very fine marble, belonging to the<br />
metamorphic limestones of a more recent date, but it is not<br />
as durable as those of an older age ;<br />
has more fissures.<br />
it is more friable, and<br />
Bird's-eye or encrinitaJ marble forms an extensive bed in<br />
the State of New York; it is a compact crinoidal limestone,<br />
containing fragments of stems and joints of crinoids<br />
of a bright pink, and other organic remains of a dark<br />
color, which, on the gray ground, give a beautiful variety.<br />
A similar limestone, susceptible of receiving a polish, occurs<br />
in the lower bed of the Niagara limestone, at Lockport and<br />
at Becraft's Mountain, near Hudson, where the organic<br />
remains are nearly similar to the first. Also the Onondaga<br />
limestone affords a similar marble, and taking a fine polish,<br />
with a much greater variety of organic remains than either<br />
pf those just described. All these limestones compose very<br />
thick beds, and are all suitable for ornamental purposes;<br />
they are a very excellent and durable building-stone, and<br />
are extensively used for the massive and beautiful locks and<br />
piers on the Erie canal, at Lockport, and as building-stone<br />
in Buffalo, Lockport, and Rochester, and the city hall and<br />
court house in Chicago have been built from it ; they belong<br />
to the group of limestones called the Niagara group.<br />
On a recent visit to Buffalo, the author's special attention
MA-KBLE. 373<br />
was directed to the wide range of marble, beginning at<br />
Harlem Bridge, New York island, where the fine white<br />
granular marble begins ; crossing thence to Hastings, twen-<br />
ty miles farther up the Hudson river, of a still finer, and<br />
also coarser white marble ;<br />
white marble ;<br />
farther on, the Dutchess county<br />
and gradually coming into the black marble<br />
region at Schenectady. At Little Falls, high cliffs of<br />
that species of limestone, with magnificent scenery, excited<br />
his admiration on passing in the railroad cars. A<br />
short visit to the State Cabinet of Geology in Albany<br />
gratified him in the extreme ;<br />
and every person desirous of<br />
being informed of the vast resources of limestone of the<br />
State of New York, cannot spend a more pleasant or instructive<br />
day than to examine the well-arranged museum<br />
of the geological formation of the State of NewT York, and<br />
of the minerals of this State and neighborhood.<br />
A short description of this class of limestones may give<br />
the reader some idea of the intrinsic value of the results of<br />
the scientific -research, accomplished through the liberally<br />
extended munificence of the several legislatures of the<br />
State, by such men as Hall, Eramons, Conrad, Mather, and<br />
Yannuxem. The visitor will perceive, on the entrance<br />
into the large hall of the Geological Cabinet, a large slab<br />
of the chalky limestone, with the thousand ammonites and<br />
orthoceratites imbedded ;. he next beholds "the bird's-eye<br />
limestone, some specimens having also thousands of sharks'<br />
teeth on the surface ; he next sees the Black river and<br />
Trenton limestone, both rough, and also fine polished specimens,<br />
inclosing the orthoceratite in its polished state, as<br />
if cut in two parts, and it makes a very beautiful appearance<br />
; the Mohawk valley and Hudson river group, with<br />
all the imbedded fossils, next attracts his attention ; the<br />
Utica slate and its large trilobites, from one to twelve<br />
inches in length, along with the Niagara limestone group,
374 A POPULAR TREATISE ON GEMS.<br />
displaying likewise the gigantic trilobite family, is not less<br />
attractive than the enormous slab of the black limestone,<br />
called the corniferous limestone, with the Marcellus shale,<br />
near Manlius, in Onondaga county. This slab contains<br />
several ammonites of one foot in length; it is called now<br />
the<br />
'<br />
ffoniatilis expansus<br />
orthoceratas marcellinius. This<br />
specimen must weigh at least one hundred pounds, and is<br />
three feet in length ; and it is certainly a very magnificent<br />
specimen.<br />
The large rhombic limestone, from St. Lawrence county,<br />
with the dogtooth spar, from Lockport, form interesting<br />
specimens in the Cabinet.<br />
mineralogical- department of the State<br />
The splendid quartz crystals, from Herkimer county and<br />
Lake George, as also the fluor spar of Jefferson county, and<br />
the beautiful green crystals of apatite, from St. Lawrence<br />
county, with the sulphate of strontia specimens, from the<br />
latter, Onondaga, and Schoharie counties, all claim their<br />
respective merits ;<br />
the labrador spar and hypersthene, from<br />
Essex county, the gypsum, sulphate of baryta, the beauti-<br />
ful rose quartz, from Fort Henry, the red sapphire crystals,<br />
from Orange county, and the amethysts, intermixed in<br />
layers with the serpentine, from Putnam county, form very<br />
fine ornamental minerals.<br />
Among the most interesting minerals of this State may<br />
be mentioned the rensselaerite, from Fort Edward ;<br />
a great<br />
many specimens of this interesting mineral, both rough<br />
and polished, may be seen in the State Cabinet. It forms<br />
irregular masses in that limestone region, has an unctuous<br />
feel of stalactite, but is of superior hardness ; resembles more<br />
the satin spar in its crystalline form ;<br />
it resembles pyroxene,<br />
but differs much from it in its hardness and specific grav-<br />
ity ; its hardne'ss is 3'5 to 4', and specific gravity 2'87 ; its<br />
color is white, yellowish-white ; has uneven fracture. This
MARBLE. 375<br />
mineral was -named in honor of the late patroon, Gen,<br />
Stephen Van Rensselaer, of Albany. This mineral abounds<br />
in St. Lawrence county, and will, no doubt, at no distant<br />
day, be wrought into many beautiful ornaments ; the polished<br />
specimens in the State Cabinet are very fine.<br />
The Potomac and breccia marble is a rock of the newer<br />
red sandstone series ; it forms a beautiful rock, and the columns<br />
of the hall of the House of Representatives, at Wash-<br />
ington, are cut from this somewhat hard material.<br />
The serpentine marble, or verd-antique, occurs in numerous<br />
localities along the belt of formations which extends<br />
from northern Vermont, through the western part of<br />
Massachusetts, Connecticut, a small portion of southern<br />
New York, New Jersey,- Pennsylvania, and Maryland ;<br />
this formation is metamorphic of a part of the Hudson<br />
river group. A very beautiful verd-antique marble occurs<br />
at Cavendish, Lowell, and Troy, in Vermont ;<br />
in Cheshire,<br />
Massachusetts, and in Milford, Connecticut. There are<br />
two kinds of verd-antique marble the true verd-antique,<br />
and the serpentine marble; the first occurs in Vermont<br />
and Milford, Connecticut, and the latter, called the com-<br />
mon, near New Haven, Connecticut.<br />
The white coarse-grained marble, from Texas, Baltimore<br />
and used<br />
county, Maryland, is quarried very extensively,<br />
in Washington City for the capitol extension, treasury, and<br />
post-office department.<br />
In Missouri occur large beds of white and reddish-white<br />
marble, in Jefferson county and near St. Louis ;<br />
the Gene-<br />
vieve marble, which is an oolitic limestone, has a very<br />
extensive formation, and is used in St. Louis and New<br />
Orleans as building-stone ; some marble quarries are full<br />
of organic remains, and some are so hard and durable that<br />
they are used for hearths, having extraordinary power to<br />
resist the action of heat.
376 A POPULAR TREATISE ON GEMS.<br />
Breccia Marble, of Lancaster county, Pennsylvania.<br />
This is a recent discovery of a variegated marble, a pure<br />
carbonate of lime, and differs materially from other mar-<br />
bles of the United States and foreign countries ; and an<br />
independent name has been given to it by its discoverer,<br />
viz. : the leocadia breccia, which forms a solid, unstratified<br />
bed of compact marble. It is admirably adapted for orna-<br />
menting churches, banks, hotels, and other public buildings,<br />
as also for private houses for mantels, tables, wainscoting,<br />
balustrades, &c. It is very easily wrought, and has, therefore,<br />
the advantage of many other marbles of the United<br />
States. This new locality bids fair to drive the foreign and<br />
more costly marbles out of the market ;<br />
as for brilliancy of<br />
color and its variegated character, and for strength and<br />
durability, it has not its equal, either in the United States<br />
or any foreign country. It is sincerely to be hoped that<br />
so valuable a bed of limestone may not be left slumbering<br />
for another century, but that the discoverer, Mr. James -W.<br />
Hale, may reap the benefit of its speedy development and<br />
general application.<br />
The New York Exhibition of 1853 was well supplied<br />
with statuary from the whole world, but -particularly from<br />
Italy. The Italian works consisted mostly of copies from<br />
the antique. The copy of the Flora of the Capitol; Barto-<br />
lini's Faith ; Harpocrates, and Cupid in a mischievous niQod ;<br />
Canova's Hebe, and Thorwaldsen's statuary, were all of<br />
great merit. Power's statues of Eve and Proserpine have<br />
been, in addition to the Greek Slave and Fisher-boy,<br />
already noticed among the great curiosities of the London<br />
Exhibition. We will enumerate the other statues in marble<br />
which were much admired at the New York Exhibition,<br />
viz. :<br />
1. A Bacchante, and Psyche, from the sculptor, Gait, of<br />
Norfolk, Va.
MARBLE. 377<br />
2. Bust of Daniel Webster ; the Husbandman's Orphan,<br />
a nude figure of a boy leaning on a spade ;<br />
ing Child,<br />
all in marble, by Pietti, New York.<br />
3. The Minstrel's Curse, by Miller, New York.<br />
and the Sleep-<br />
4. Christ in the Sepulchre, by Creswell, Brooklyn.<br />
5. Bust of Dr. John Green, of South Carolina, and one<br />
of Charles Allen, of Massachusetts, by Kinney, of Worces-<br />
ter, Massachusetts.<br />
6. Head of a Female, by Ives, Connecticut.<br />
7. Bust of Daniel Webster, by King, Boston.<br />
8. A veiled Cupid, by Moon, New York.<br />
9. Head of Jupiter, and statuettes, by*Ferris & Taber,<br />
New York.<br />
10. Cupid, and Charity, a female figure seated, with an<br />
infant in her arms, life size, by Baudel, London.<br />
11. Busts of Daniel O'Connell and Father Mathew, from<br />
Hagan, Dublin.<br />
12. Bust of Jenny Lind, by Durham, London.<br />
13. Bust of Palmerston, by Sharp, London.<br />
14. Ruth and Naomi, by Kirk, Dublin.<br />
15. Bust of Louis Napoleon, emperor of France, by<br />
Deumier, Paris.<br />
16. Statue of Racine, by D'Angier, Paris.<br />
17. Lesbia, by L'Eveque, Paris.<br />
18. Damalis, by Etex, Paris.<br />
19. A veiled head ; a sleeping Cupid ; Psyche reposing,<br />
and bust of Prayer, by De Bokeleer, Antwerp.<br />
20. Statue of Venus and Cupid, by Fraikin; Brussels.<br />
sels.<br />
21. Two Children Sleeping, as a group, by Geess, Brus-<br />
22. Hebe, from Canova, by Lazzerini, Rome.<br />
23. A Danaide, head of an Amazon, and bust of Queefl<br />
Victoria, by Bariata, Rome.<br />
24. Iris, by Cartei, Florence.
378 A POPULAR TREATISE ON GEMS.<br />
ence.<br />
25. Hagar and Ishmael in the Desert, by 'Catelli, Flor-<br />
26. Lord Palmerston, by Fabrucci, Florence.<br />
27. Harpocrates, the God of Silence, full length ; and<br />
Cupid in a mischievous mood, by Santarelli, Florence.<br />
28. Statue of Truth, a tipsy Bacchus, and Virgin of the<br />
of the Eucharist, a bas-relief; by Cambi, Florence.<br />
29. The Betrothed, and the Son of William Tell, by<br />
Romanelli, Florence.<br />
30. The Genius of Sacred Music, and Laura, by Consani,<br />
Florence.<br />
31. The Sleep of Innocence, by Dupri, Florence.<br />
32. John the Baptist sleeping, by Magi, Florence.<br />
33. Death of Ferruccio, by Giampaoli, Lucca.<br />
34. Rebecca, Faithful Love, the Child's First Grief, bust<br />
of Cleopatra, and bust of Heloise, by Vaspi, Florence.<br />
35. The Mendicant, by Strazza, Rome.<br />
36. Shepherdess and Bird, the Guardian Angel, and<br />
Psyche sorrowing, by Bimaimi, Rome.<br />
37. Cupid leaning on a wine-skin, by Strechi, Rome.<br />
38. Cupid with the arms of Mars, the Sacrifice of a God,<br />
and three Female Dancers, by- Jerichau, Rome.<br />
39. Columbus, Staffetti, Carrara.<br />
40. A Bacchante, a nymph wreathing herself with flow-<br />
ers, the Genius of Summer, the Genius of Spring, Herminia<br />
writing the name of Tancred, and Poetry, by Pelliccia,<br />
Carrara.<br />
41. Cupid, Psyche, and Venus of the Louvre, by Fabri-<br />
cotti, Carrara.<br />
42. The Flora of the Capitol, Bartolini's Faith, the<br />
Dying Gladiator, bust of the Saviour, St. John the Baptist,<br />
bust of Rousseau, by Baratta, Carrara.<br />
43. Pope Pius IX., by Tenerasie, Carrara.<br />
44. Bust of Washington, by Bagazzi, Carrara.
MAKBLE. 379<br />
45. Cop/of the Warwick Vase, Flora of the Capitol, the<br />
Pet Bird, Apollo Belvidere, Copernicus,<br />
Diana of the<br />
Louvre, Dante, Jupiter, Shakspeare, Madonna, and Faith,<br />
by Marchetti, Carrara.<br />
46. Marcus Tullius Cicero, and Paris, by Fontana, Car-<br />
rara.<br />
47. The Shepherdess and Lamb; a Struggle<br />
Heart, by Orlandi, Carrara.<br />
for the<br />
48. Ceres, Venus, Child with a Bird, Psyche, Poetry,<br />
and Vincenzo Gioberti, by Bruneri, Turin.<br />
49. The Virgin mourning over the dead body of Christ,<br />
by Angero, Turin.<br />
50. The Virgin and Angel of Annunciation, by Galeazzi,<br />
Turin.<br />
5 1 . Hebe offering Nectar to the Eagle, by Kachszman,<br />
Milan.<br />
52. Boy riding on a Crawfish, a Tortoise, Leda with the<br />
Swan, Innocence, and veiled head, by Croff, Milan.<br />
53. Atala and Chactas, colossal bust of the Redeemer,<br />
by Fraccardi, Milan.<br />
54. Infant Saviour, Child on the Waves, by Galei, Milan.<br />
55. The Deserted, veiled head, Cupid forcing the Roses,<br />
nest of Cupids, cage of Cupids, and basket of Cupids, by<br />
Motelli, Milan.<br />
56. Sleeping Venus, by Rados, Milan.<br />
57. Resignation, by Tandardini, Milan.<br />
58. The Fisher-boy, by Cacchi, Milan.<br />
59. The Soldier's Son, by Jorini, Milan.<br />
60. Head of the Saviour, and colossal bust of Vincenzo<br />
Monti, by Langiorgio, Milan.<br />
61. Virgin grieving, by Nezeo, Milan.<br />
62. Eve after the Fall, by Ragani, Milan.<br />
And many more, less notable. All of these sculptures<br />
were in Italian marble.
380 A POPULAR TREATISE ON GEMS.<br />
Sfttlactite and Stalagmite.<br />
It occurs in large tuberous, undulated masses, botryoidal.<br />
mammillary, or concretional, either in icicles or circles ;<br />
has a fibrous fracture ; is translucent ; of a pearly lustre ;<br />
color generally yellowish-white and white ; its composition<br />
is calcareous spar ;<br />
it originates in caverns, through which<br />
water, holding this in solution, filters, and on its ultimate<br />
evaporation leaves the carbonate of lime in various forms,<br />
which sometimes resemble altars, pillars, animals, &c.<br />
Those pillars or icicles which are pendant from the roof,<br />
and those rising from the base, are sometimes divided into<br />
stalactite for the former, stalagmite for the latter. But the<br />
cause of their existence is the same, and there ought not<br />
to be any distinction in their name.<br />
Ornaments of stalactite in the shape of vases, &c., are<br />
often seen in fancy stores. The greatest localities of this<br />
mineral are, the Grotto of Antiparos, and Bauman's Cave,<br />
in the Hartz, which I visited in 1827, and which displays<br />
gigantic stalactites; also in Derbyshire. In the United<br />
States, are very celebrated caves which yield this article.<br />
These have been described by my friend, Charles Cramer,<br />
Esq., late Russian Vice Consul at New York, now<br />
of the Isle of Wight, an enthusiastic mineralogist, of St.<br />
Petersburg, in a pamphlet published by the Imperial<br />
Mineralogical Society of St. Petersburg, in the German<br />
and as this interesting little work is not accessi-<br />
language ;<br />
ble to all, I will here translate the list of all the caves enu-<br />
merate'd by him as North American. We would observe<br />
that these are not all situated in limestone regions, neither<br />
do they all furnish stalactites.<br />
Canada. Grotto in the Niagara ; a cave in Lanark,<br />
Upper Canada ;<br />
a smaller cave at the same place.<br />
New Hampshire. The Devil's cave.<br />
'
Vermont. Caves in Bennington ; caves in Dorset.<br />
381<br />
Massachusetts. Natural bridge and cave at Nahant ;<br />
natural bridge over the Hudsop brook ;<br />
cave near Sunder-<br />
land ; cave in Berkshire ; two caves near New Marlbo-<br />
rough ; cave near West Stockbridge ; cave in Lanesboro ;<br />
cave in Adams ; Purgatory, near Sutton.<br />
Connecticut. West Rock cave, New Haven.<br />
Rhode Island. Purgatory, near Newport ; Spouting<br />
cave, near Newport. -'4*;<br />
New York. Cave near Watertown ; cave at Niagara ;<br />
Ball's cave Knox's cave ; ; Monito, at Wigwam, or Devil's<br />
Abode ; Esopus cave.<br />
Pennsylvania'. Devil's Hole, in Bucks county ; cave on<br />
the Swatera river.<br />
Maryland. Hughes' cave ; cave at Harwell.<br />
Virginia. Weyer's cave ; Wreast's cave ; Madison's<br />
cave ; Zane's cave ; Blowing cave, near Panther Dale ;<br />
Greenbriar's cave ; cave on the Kanhawa river ; Chapin's<br />
cave ; Johnson's cave ; Allen's cave ; Ruffner's cave ; Roger's<br />
cave ; Reid's cave ; Natural Tunnel in Scott county ; Natu-<br />
ral Bridge in Rockbridge county.<br />
Ohio. Mason's, cave ; Nature's Building, or Cave in the<br />
Rock.<br />
Indiana. Epsom Salt cave ; cave near Corydon.<br />
Kentucky. Boone's cave ; Russell's cave ; White cave ;<br />
Mammoth cave ; cave on Crooked creek.<br />
Tennessee. Big-bone cave ; Arched cave.<br />
South Carolina. Great Flat Rock cave ; Lover's Leap.<br />
Georgia. Nicojack cave.<br />
Missouri. Ashley's cave.<br />
Mississippi. Abode of the Great Spirit on the North<br />
West Coast ; cave on Copper river.<br />
Mexico. Dantoe cave; Chamacasapa cave; San Felipe<br />
cave.<br />
'
382 A POPULAR TREATISE ON GEMS.<br />
Cuba. Cave near Matanzas.<br />
Hayti. Cave near St. Domingo.<br />
Peru. Cave in the Andes.<br />
New Andalusia. Canipe cave.<br />
Mr. Cramer mentions the size of the stalagmites in the<br />
antechamber of Weyer's cave, as being twelve feet high ;<br />
those in Solomon's Temple, of the same, twenty-five feet<br />
high, which are nearly transparent; and its Hermit's Chandelier,<br />
four feet high, and twelve feet in circumference; the<br />
colossal stalagmite in Washington Hall, which is said to<br />
represent the Father of his Country wrapped in his cloak ;<br />
Pompey's column, thirty feet high ;<br />
thirty feet in circumference.<br />
Egyptian Marble.<br />
also Babylon's Tower,<br />
This is generally milk-white, or grayish-white and bluish,<br />
and also black and red, which is called the rosso antico; it<br />
is of a close granular structure, and was a great favorite<br />
with the ancient architects.<br />
Italian Marbles.<br />
"With these may be counted the Parian marble ; the Pen-<br />
telian marble ; the Venetian or Lombardy marble, which<br />
is quite translucent ; the Luni and Carrara marble ; and the<br />
Laconian marble, or verd-antique. They have all yielded<br />
materials for the most ancient Greek and Italian sculptors.<br />
The Venus de Medici, the Diana Hunting, and Venus leaving<br />
the Bath, are of Parian marble ; a Bacchus in repose, a<br />
Jason, a Paris, and many Grecian monuments, are from<br />
Pentelian marble, which comes from the vicinity of<br />
Athens.
MAEBLE. 383<br />
American Marble.<br />
(Additional from the former edition of this treatise.)<br />
The varieties of marble, which substance is inexhaustible<br />
in the United States, are very numerous ;<br />
and I am proud<br />
to assert,' that for architectural and ornamental purposes,<br />
they will successfully compete with those of any foreign<br />
country. The colors are various, from the snow-white to<br />
the black with gold and grass-green veins. A small dis-<br />
trict in New England, of about fifty miles in extent, con-<br />
centrates, I may say, the marbles which may<br />
be collected<br />
in Europe through a space of two thousand square miles ;<br />
for we find in the county of Berkshire, and that of New<br />
Haven, the representatives of marbles from Italy and Ire-<br />
and the discoveries which are constantly being made<br />
land ;<br />
of additional marble localities are a source of great satisfaction.<br />
Thirty years ago, the City Hall, of New York<br />
city, was built of marble from West Stockbridge, Massa-<br />
chusetts, which was transported at great expense, a distance<br />
of over four hundred miles ; whereas, afterwards, the<br />
same quality of marble was discovered on New York island,<br />
but a few miles distant. According to Professor Dewey,<br />
the county of Berkshire alone turned out forty thousand<br />
dollars' worth of marble several years ago. I will here<br />
enumerate a few of the most interesting marbles:<br />
a. The Philadelphia marble, which is snow or grayish<br />
white, and sometimes variegated with blue veins, w r hich<br />
takes a very high polish.<br />
Z>. The Potomac marble, which is properly called a<br />
breccia, being composed of rounded and angular fragments<br />
from the size of a pea to that of an ostrich's egg.<br />
Its colors are red, white, gray, and blackish-brown, intermixed<br />
; it takes a very fine polish, and forms a most beau-<br />
tiful ornamental stone. It comes from the banks of the
384 A POPULAR TREATISE ON GEMS.<br />
Potomac, in Maryland. As specimens of this, we would<br />
refer to the .columns in the House of Representatives at<br />
Washington, which are twenty feet high, and two feet in<br />
diameter.<br />
c. The Yerd- Antique, of New Haven, Connecticut. This<br />
marble is intermixed with serpentine veins, and makes a<br />
most beautiful appearance. There are inexhaustible quar-<br />
ries of it at New Haven and Milford ; it bids fair to rival<br />
every other ornamental stone in the world. Four chimney-<br />
pieces of this mineral were purchased for the Capitol at<br />
Washington; and I lately examined a splendid centre<br />
table, wholly cut from this marble, that was exhibited at<br />
the tenth annual fair of the American Institute. It is to<br />
be hoped that some company may undertake to introduce<br />
this marble more extensively into notice, for it does not yet<br />
appear to be sufficiently known among our wealthy citizens:<br />
the enterprise would be well rewarded. Large slabs<br />
may be seen at the New York Lyceum of Natural History,<br />
and in the cabinet of Yale College, New Haven. I possess a<br />
very fine, large slab, polished. Portsmouth, Vermont, likewise<br />
furnishes splendid verd-antique, specimens of which<br />
may be seen at the American Institute, in New York.<br />
d. Berkshire county, in Massachusetts, may justly be<br />
called the marble pillar of the United States ; and, as Pro-<br />
fessor Hitchcock remarks, the inhabitants of that county<br />
cannot but regard their inexhaustible deposits of marble<br />
as a rich treasure to themselves, and an invaluable legacy<br />
to their posterity. The towns, West Stockbridge, Lanes-<br />
borough, New Ashford, Sheffield, New Marlborough, and<br />
Adams, in that county, keep thousands of hands constantly<br />
working in their quarries. In 1827, two thousand seven<br />
hundred tons of marble were exported from that town ; and<br />
in 1828, a block of from fifty to sixty feet square, and eight<br />
thick, was raised by one charge of gunpowder.
e. White, fine, granular marble, bearing<br />
semblahce to the celebrated Carrara marble,<br />
385<br />
the closest re-<br />
is' obtained<br />
from Smithfield, Rhode Island ; Stoneham, Massachusetts,<br />
and near Hastings, on the Hudson river.<br />
Shell Marble.<br />
This mineral is a secondary marble, and is called also<br />
conchitic marble, on account of its containing petrified<br />
shells, which, when polished, conimunicate to their matrix,<br />
the marble, a most beautifully variegated appearance.<br />
a. The Lumachella marble is a kind which is very scarce;<br />
it has a gray or brown ground, interspersed with shells of<br />
a circular form and golden color, and when held towards<br />
the reflection of light, displays red, blue, and green tints,<br />
like those of the precious opal or iridescent labrador.'<br />
It is sometimes seen in the form of pins and other jewelry,<br />
but stands,, on account of its scarcity, very high in price ;<br />
the only locality is in Carinthia ; . one formerly in Devon-<br />
shire, England, being exhausted. Some splendid specimens<br />
from Carinthia, are in the collection of Baron de Lederer,<br />
Austrian consul for this city ; and a very fine specimen of<br />
the lumachella, at the Boston Society of Natural History,<br />
was marked with the locality of Neufchatel.<br />
b. Panno di morto, or funeral pall, is a deep black<br />
marble, with white shells, like snails; it is only seen at<br />
Rome, and is very scarce.<br />
c. Bristol marble, from England, is a black marble, inter-<br />
spersed with white shells.<br />
d. Italian shell marbles from Florence, Lucca, and Pisa,<br />
are red, containing white shells (ammonites).<br />
e. French shell marbles are very numerous ; those from<br />
Narbonne are black with white belemnites ; that from<br />
Caen is a brown marble with madreporites j and those from<br />
17
386 A POPULAR .TREATISE ON GEMS.<br />
Languedoc are of a fiery red color, mixed with white and<br />
of this Napoleon's eight columns for<br />
gray univalve shells ;<br />
his triumphal arch in the CarouselJ at Paris, were cut.<br />
f. The United States "have a great many shell-marble<br />
quarries ; but they are all black and gray. Those of Trenton<br />
Falls, Little Falls ; near Seneca lake ; Northumber-<br />
land county, Pennsylvania; Bernardston, Massachusetts,<br />
and Hudson, New York, contain either trilobitea or encri-<br />
nites ; some take a very fine polish.<br />
PISOLITE AND OOLITE.<br />
These minerals are likewise composed of carbonate of<br />
lime; they occur massive, and in distinct concretional<br />
layers, either in the form of peas or other round grains or<br />
pebbles, and are of white, yellowish-white, brownish, or<br />
reddish color ; when cut and polished, they make a fine<br />
ornamental stone, and present a very effective appearance.<br />
The former is found in alluvial deposits of the hot water<br />
mineral springs of Carlsbad, in Bohemia, and the baths of<br />
St. Philip, in Tuscany ;<br />
the latter forms large beds in Eng-<br />
land and France. The city of Bath, in England, is mostly<br />
built of this limestone.<br />
ROCK OF GIBRALTAR.<br />
This is likewise a carbonate of lime ; occurs massive,<br />
mostly striped ; is yellowish-white, yellow, and brownish ;<br />
is only found in that rock from whence it takes its name,<br />
and has been heretofore a great favorite for jewelry and<br />
other ornaments. At this day we see in shops and private<br />
houses, pins, brooches, ear-rings, seals, cane-heads, snuff-<br />
boxes, letter-holders, vases, urns, candelabras, obelisks, &c. 3<br />
formed of it. It takes a high polish.
APATITE. 387<br />
APATITE.<br />
This mineral was named by Werner, on account of its<br />
color being so deceptive (anaraa), to deceive), as it resembles<br />
the color of some -other precious stones ; it occurs in six-<br />
sided prisms, massive and globular ;<br />
has a conchoidal frac-<br />
ture ; a vitreous lustre ; color usually sea-green, bluish-green,<br />
or violet-blue, sometimes white, occasionally yellow, gray,<br />
and red ; is transparent and opaque ; it resembles the beryl<br />
and emerald, but is distinguishable by color and hardness ;<br />
hardness, 4'5 to 5 ; specific gravity,<br />
3 to 3'235. A bluish<br />
opalescence is observed in the direction of the vertical axis<br />
in some specimens, especially in the white variety; fracture<br />
conchoidal and uneven ; brittle. Some varieties are phos-<br />
phorescent when heated, others become electric by friction.<br />
It is infusible alone before the blowpipe, except at the<br />
edges; dissolves slowly in nitric acid, and without effervescence.<br />
Apatite usually occurs in primitive rocks ;<br />
is often found<br />
in veins of primitive limestone traversing granite, it also<br />
occurs in serpentine and in ancient volcanic rocks.<br />
It contains about ninety per cent, subsesquiphosphate of<br />
lime, and the rest is chloride and fluoride of calcium. On<br />
account of its phosphoric acid, the compact varieties of<br />
apatite have become an important article of trade for agri-<br />
cultural purposes.<br />
The principal localities are in Saxony, at Ehrenfriders-<br />
dorff, in the Hartz mountains, where the author collected,<br />
in his youthful years, some magnificent crystals; also in<br />
Bohemia, at Schlackenwald ;<br />
in Cumberland arid Devon-<br />
shire, England; at t. Gothard, in Switzerland;<br />
and a<br />
greenish-blue variety, called moroxite, is found in Norway,<br />
at Arendal.<br />
Asparagus stone, which is of a yellow color and trans-
388 A POPULAR TREATISE ON GEMS.<br />
lucent, is found at Estremadura, in Spain, of which many<br />
fine specimens may be seen at the Academy of Natural<br />
Sciences of Philadelphia, in Maclure's collection ; also in<br />
Zillerthal, Tyrol, where it is imbedded in talc. The phosphorite,<br />
or massive varieties, from Spain and Bohemia, has<br />
been found in large beds. In the United States it occurs<br />
in a vein of limestone intersecting the granite at Gouver-<br />
neur, St. Lawrence county, New York, and crystals of<br />
ten to twelve inches long and one and a half to two inches<br />
in diameter, of fine sea-green color, were formerly found<br />
in abundance.<br />
Yale College has some fine specimens of this crystallized<br />
variety, from Baron Lederer's cabinet. Professor Shep-<br />
herd, Mr. Francis Algar, and Dr. Charles T. Jackson, in<br />
Boston, possess many fine and large crystals. Mr. Kranz,<br />
in Bonn, was fortunate to procure, through his collector,<br />
some gigantic crystals of this beautiful mineral. There are<br />
some other localities of the crystallized variety in the<br />
United States, such as Amity, New York, where it occurs<br />
of a green color in white limestone, presenting the primary<br />
form, and accompanied with pyroxene and scapolite. Crystallized<br />
and massive specimens of a bluish-green color<br />
occur at Boston, Massachusetts, associated with sphene and<br />
petalite. Reddish-brown crystals,- of one inch in length,<br />
have been obtained from a granite vein in Greenfield, New<br />
York. The massive variety of phosphate of lime from<br />
Crown Point, New York, has furnished several thousand<br />
tons for export to England as a fertilizing agent, and the<br />
concretional variety of phosphate of lime from Dover and<br />
Franklin, in New Jersey, has likewise yielded considerable<br />
quantities for a manure. These two latter varieties have<br />
been treated with sulphuric acid (oil oT vitriol),<br />
in order to<br />
obtain a superphosphate of lime, which is now considered<br />
the most useful vehicle to enrich the soil, and to produce
MICA. 389<br />
the most prolific crops. Liebig and Johnstone, the two<br />
great agricultural chemists, have demonstrated beyond any<br />
controversy that .the resuscitation of worn-out soils depends<br />
materially upon the addition of phosphate of lime ; and<br />
hence the application of bone-dust, which is a phosphate of<br />
lime, and guano, which contains the latter ingredient with<br />
the ammoniacal salts in combination, of which at the<br />
present day 100,000 tons are annually consumed by the<br />
farmer, along with the artificially prepared superphosphate<br />
of lime, are well known, but do not belong here.<br />
LEPIDOLITE.<br />
This mineral derives its name from the Greek language,<br />
from its scaly structure ; it occurs massive, presenting an<br />
aggregate of minute, shining, flexible scales or hexagonal<br />
plates ; it has a splintery fracture ; a glistening and pearly<br />
lustre; is translucent on the edges; its colors are lilac,<br />
rose-red, pearl-gray, greenish-yellow, and blue ;<br />
it is<br />
scratched by glass, and yields to the knife ; has a specific<br />
gravity of 2'81 ; is fusible with ease into a transparent<br />
globule. It is found in granite and primitive lime, in<br />
Monrovia, France, island of Elba, Corsica, Sweden, and in<br />
the United States, in Maine, New Hampshire, Vermont,<br />
and Massachusetts. It is cut in Europe for various orna-<br />
ments, such as plates, vases, snuif-boxes, &c., and will, 'I<br />
trust, at some future day, be more extensively<br />
jewelry ; for there are some variegated specimens<br />
used in<br />
of a<br />
peach-blossom color, and very fine granular structure,<br />
which are extremely beautiful.<br />
MICA.<br />
This mineral occurs crystallized, in six-sided tables and<br />
oblique rhombic prisms, and massive ; also, disseminated ;
390 A POPULAR TREATISE ON GEMS.<br />
it has a perfectly foliated structure ; a glittering and<br />
metallic lustre ; is transparent and translucent ; very fusi-<br />
ble and elastic ; its colors are white, green, black, brown,<br />
peach-red, yellowish, and bluish ;. it has a specific gravity<br />
of 2'7. It is found in primitive rocks, and forms an ingredient<br />
in granite, gneiss, mica slate, and other rocks, where<br />
it more or less predominates ; its localities are, therefore,<br />
universal, but in Siberia it forms large beds, and is quarried<br />
for special purposes, such as a substitute for glass windows ;<br />
and although the United States afford ample localities of<br />
here for<br />
it, yet a few years ago quantities were imported<br />
the doors of Nott's stoves.<br />
The plumose mica is a beautiful variety, and derives its<br />
name from its resemblance to a quill or plume, the lamellar<br />
or fine delicate crystals diverging in such a manner as to<br />
present this appearance. It is of a pearl-gray color. It is<br />
found in the United States, at Williamsbury, Mass., Hart-<br />
ford, Conn.,, and many other places. The green mica is of<br />
a beautiful grass-green color, and is found in Brunswick,<br />
Maine. The rose-red mica is a very beautiful mineral, and<br />
is found in numerous places, in this country ; principally at<br />
Goshen, Chesterfield, Mass.; Acworth, N. H. ; Bellows<br />
Falls, Vt., &c. Mica may, when of good colors, be used<br />
for jewelry and other ornaments, as well as the lepidolite.<br />
PYRITES.<br />
This mineral is called sulphuret of iron, iron pyrites, and<br />
markasite. It occurs crystallized in many forms ;<br />
such as<br />
the cube, octahedron, and dodecahedron ; also massive,<br />
disseminated, capillary, and cellular;<br />
it has a conchoidal<br />
fracture ; a brilliant metallic lustre ; its colors are bronze,<br />
yellow, brass-yellow, and steel-gray.<br />
This mineral takes a<br />
very high polish, and from its fine lustre looks extremely
PORPHYRY. 391<br />
well when cut in the form of a brilliant or rose. It was<br />
formerly much -used in jewelry for ear-rings, rings, pins,<br />
and necklaces. It was, in former times, considered a great<br />
preservative of health. It is now but seldom seen, except<br />
in mineralogical cabinets.<br />
ROSE MANGANESE.<br />
This mineral is called in mineralogical works the silicious<br />
oxide of manganese, and also the carbonate of manganese.<br />
It occurs massive; has a foliated structure; a conchoidal<br />
fracture ; a shining lustre ; it scratches glass ; its colors are<br />
rose-red, reddish, and yellowish.<br />
It is found in Siberia, Sweden, Hungary, England ; and<br />
in the United States, at Middlebury, Vt., and at Cummington<br />
and Plainfield, Mass., where, according to Professor<br />
Hitchcock, the silicious oxide, or according to Dr. Thompson,<br />
the bisilicate of manganese is found in great abundance.<br />
Since it takes a very high polish, and is much wrought at<br />
Ekaterinenburg, in Siberia, into many ornaments, it is confidently<br />
to be hoped that it may also find its amateurs in<br />
this country, as it is very easy to cut and polish, and the<br />
material is so plenty.<br />
PORPHYRY.<br />
This mineral forms rocks in a geological sense, but is<br />
properly a compact felspar. It has various' colors and<br />
shades, and contains imbedded crystals of felspar and<br />
quartz. The name porphyry signifies purple, from iroptyvpa,<br />
such having been the usual color of the ancient porphyries ;<br />
the same rock exhibits, however, almost every variety of<br />
color ; it is the hardest of all rocks, and when polished, Is<br />
probably the most enduring. It is much used in Europe<br />
for ornamental and architectural purposes ; also for slabs,<br />
mortars, and other articles.
392 A POPULAR TREATISE ON GEMS.<br />
In the United States, porphyry has never been used for<br />
any purpose ; but Professor Hitchcock f emarks, in his<br />
Geological Report of the State of Massachusetts, that it<br />
would be strange if an increase of wealth and refinement<br />
should not create some demand for so elegant and enduring<br />
a rock as porphyry. In the same excellent work the author<br />
divides porphyry into four varieties, as occurring in Massa-<br />
chusetts, in the neighborhood<br />
of Boston :<br />
1st. Compact felspar, with several predominating colors;<br />
the one with yellow, resembling the Turkey stone; one<br />
with red, from brownish to blood-red, closely resembling<br />
jasper ; one with a rose-red color, resembling the rose petro-<br />
silex of Europe.<br />
2d. Antique porphyry ; closely resembling that European<br />
porphyry which was employed by<br />
the ancients in monu-<br />
ments and ornamental furniture and forms, and is, when<br />
polished, a beautiful ornament. It presents numerous varieties<br />
and shades of color : one of the most elegant is the<br />
light-green ; then a deep-green ; red of various shades ;<br />
reddish-brown ; black, or nearly so ; gray, and purple ; and<br />
the imbedded crystals are usually of a light color, some-<br />
times white, brown, and greenish.<br />
3d. Porphyry with two or more minerals imbedded, and<br />
having a base of common felspar.<br />
This mineral is between<br />
sienite and porphyry, resembling the trachytic porphyry,<br />
and is generally unfit for ornamental purposes ; the quartz<br />
which it contains is hyaline and smoky.<br />
4th. The brecciated porphyry, which is composed of an-<br />
gular fragments of porphyry and compact felspar, reunited<br />
the fragments are also of<br />
by a paste of the same material ;<br />
various colors, usually, however, gray and red ;<br />
the rock is<br />
very hard, and when polished, furnishes specimens of great<br />
delicacy for ornamental purposes.<br />
Porphyry is much used in England for paving stones, in
SEENITE. 393<br />
the entrance halls of large public buildings or private<br />
mansions, and the Cornwall porphyry is particularly cele-<br />
brated- for its various tints of colors. The author distinctly<br />
recollects four slabs : one was a black slab ; another, red ;<br />
a third, green; and a fourth, a large slab, containing<br />
twenty-four specimens of various variegated rocks of porphyry.<br />
Also, the elvan-stone, from the quarries of New<br />
Quay, in Cornwall, which is a beautiful porphyry. The<br />
large slab, weighing about eight hundred pounds, was of<br />
very fine red color it was without ;<br />
flaw or defect.<br />
In Prussia porphyry is abundant, and there were some<br />
fine specimens in the London Exhibition, such- as a table, a<br />
small column and tazza ;<br />
the latter was a round slab of red<br />
color and fine texture, and the tazza vase and pedestal were<br />
of the same material.<br />
From Sweden and Norway a sienitic porphyry, of grayish-red<br />
color, was also in the London Exhibition.<br />
The porphyry vase in the Berlin Museum, which, accord-<br />
ing to the author's recollection, is about eight feet high<br />
and six feet in diameter, is well deserving a place hi this<br />
treatise, as it is unique of its kind in the world.<br />
SIEXITE.<br />
This rock is composed essentially of felspar and horn-<br />
blende, and sometimes contains quartz or mica, or both.<br />
When polished, it forms the most splendid ornamental<br />
stone of all rocks ; it is very hard ; and its color and the<br />
mode of distribution of the various ingredients,' make it<br />
very agreeable to the eye. It much resembles granite, and<br />
is often almost identical with it ;<br />
but by close inspection it<br />
may be distinguished from the want or addition of the<br />
component ingredients.<br />
Professor Hitchcock describes six varieties of sienite:
394 A POPULAR TREATISE ON GEMS.<br />
1st. That sienite which is composed of felspar and horn-<br />
blende, when the first is white, greenish, and yellowish, and<br />
the latter inyariably black.<br />
2d. Felspar, quartz, and hornblende ; the first is foliated,<br />
and commonly of grayish, bluish, or yellowish color ; the<br />
second from quite light to dark color and hyaline ;<br />
and the<br />
latter is black. Under this variety the quarries at Quincy<br />
and Cape Ann have been arranged by the author (which<br />
are generally called granite), on account of the absence of<br />
mica. The Quincy granite, or rather sienite, is that cele-<br />
brated architectural material used in the cities of Boston<br />
and New York, for those huge and magnificent edifices,<br />
public as w^ell as private, erected within the last six years ;<br />
and it may be supposed that five thousand buildings in the<br />
city of New York have been constructed with this splendid<br />
article.<br />
3d. Felspar, hornblende, quartz, and mica. This rock,<br />
likewise, has a beautiful appearance, but is, as yet, less<br />
wrought than the other varieties. The felspar and hornblende<br />
are predominant. The quartz is in small grains, and<br />
the mica is black,<br />
4th. Porphyritic sienite ; its base is quartz and felspar,<br />
and the hornblende is almost entirely absent ;<br />
it has a<br />
porphyritic aspect ; the felspar predominates. It is the<br />
most ornamental stone when polished.<br />
5th. Conglomerated sienite; it is a quarternary com-<br />
pound of felspar, hornblende, quartz, and mica, but all in<br />
rounded or conglomerated masses, having the aspect of a<br />
pudding-s'tone ;<br />
the nodules are from half an inch to six<br />
inches in size, and may be easily broken out of the mass,<br />
and the hornblende predominates mostly in them. It is<br />
unfit for architectural purposes.<br />
6th. Augite sienite ; in this rock the hornblende ia<br />
present and rnica absent. It is composed<br />
of black horn-
SIEXTTE. 395<br />
blende, greenish augite, and yellowish felspar ; all, except<br />
the felspar, presenting a crystalline structure; it is also<br />
composed only of augite and felspar.<br />
The name of the rock sienite was originally derived from<br />
Syene, in Upper Egypt, from whence the first specimen<br />
was procured ; it was examined and identified by Werner ;<br />
many of the Egyptian monuments, such as Cleopatra's<br />
Needle, and Pompey's Pillar, were obtained from there.<br />
There are valuable quarries of sienite in abundance in<br />
the State of New York. It is a durable and beautiful<br />
stone, and may be quarried in large' blocks, but on account<br />
of its great hardness requires much labor to dress it.<br />
Along the North River there are many<br />
localities : An-<br />
thony's Nose, or Anthony s Face, which is a mountain in<br />
the northwest corner of Putnam county, opposite Fort<br />
Montgomery. It is called so in consequence of the profile<br />
bearing a rude resemblance to the human face, that may<br />
be seen in one position, when passing it ; but on account of<br />
its steepness, being five hundred feet in height, it is more<br />
generally called Breakneck Mountain. Here is the granitic<br />
sienite. It is composed of a darkish-gray colored felspar,<br />
with a little black hornblende.<br />
In Peekskill bay, on the Hudson river, and the adjoining<br />
hills for five miles in length, very valuable quarries of this<br />
fine rock may be quarried.<br />
The sienite rock of the Highlands is veTy extensive ;<br />
such as the Target rock on Constitution Island, opposite<br />
West Point, and all along the slopes of the mountains in<br />
the Highlands, there are boulders and blocks of this valu-<br />
able and useful rock.<br />
Fort Putnam, near West Point, and the base of Butter<br />
Hill, four miles north of West Point, are composed of sienite.<br />
When it was ascertained that the famous rock from<br />
Syene, in Upper Egypt (so much employed in ancient
396 A POPULAR TREATISE ON GEMS.<br />
monuments), and from which the name of sienite was de-<br />
rived, was nothing but granite with black mica, and also,<br />
that Mount Sinai, in Arabia, was composed of genuine<br />
sienite, a French geologist proposed to substitute sinaite<br />
for sienite, but the name, although a good one, has never<br />
been adopted.<br />
The Quin cy and Cape Ann sienite, which is sent from<br />
Massachusetts to all parts of the United States, and forms<br />
such a beautiful architectural material, is composed of<br />
felspar, quartz,<br />
and hornblende.<br />
GRANITE.<br />
This rock is composed of quartz, felspar, and mica, and<br />
forms the crust of our globe. It occurs over the whole<br />
earth, and the eastern part of the United States is abund-<br />
antly furnished with this valuable mineral. As a building<br />
material it has been most extensively used for the last ten<br />
in Decem-<br />
years ; but the great fire in New York, which,<br />
ber, 1835, consumed seven hundred buildings, among<br />
which about two hundred were of granite, has given a<br />
sufficient proof that granite is> in this changeable climate,<br />
unfit for a building material, but that it may be usefully<br />
employed for ornamental and architectural purposes, where<br />
it is not constantly exposed to the atmosphere and weather,<br />
which make it so liable to decomposition.<br />
Nevertheless, granite continues to be generally employed<br />
in the erection of public buildings, warehouses, bridges,<br />
&c., and begins to form an important pecuniary object to<br />
the merchant and mechanic ; and on this account I cannot<br />
forbear to. treat more fully on its general characters, and I<br />
must confess that the rich granite treasures of Connecticut,<br />
Rhode Island, and Massachusetts, which I had occasion to<br />
examine a short time since, on a journey into those regions,
GEANTTE.<br />
397<br />
deserve fully all the encomiums bestowed upon them in<br />
Hitchcock's Report on the Geology of Massachusetts, and<br />
in Shepherd's Report on the Geological Survey of Connec-<br />
ticut. So abundant and large are the granite rocks in the<br />
eastern part of the United States,* that some single locali-<br />
ties are sufficient to supply many countries with this lucra-<br />
tive article.<br />
Professor Hitchcock divides the granite of Massachusetts<br />
into four varieties, viz :<br />
1. Common granite, which, according to him, embraces<br />
nine tenths of the granite in Massachusetts : the ingre-<br />
dients are a distinct crystalline structure, of mixed and dis-<br />
criminating colors.<br />
2. Pseudomorphous granite is that variety in which the<br />
mica separates distinctly the other ingredients, which are<br />
closely mixed.<br />
3. Porphyritic granite : it contains, besides the usual<br />
composition of quartz, felspar, and mica, distinct imbedded<br />
crystals of felspar.<br />
4. Graphic granite : this variety consists of quartz and<br />
felspar only ; the cross-fracture presents the appearance of<br />
written characters.<br />
Professor Shepherd divides the ornamental granite of the<br />
State of Connecticut into eight different types, viz. :<br />
1. Gray granite.<br />
2. White granite. This variety I have examined myself<br />
in Plymouth, Connecticut, and so beautiful was its color<br />
and close granular texture, that I took it at a distance for<br />
a sandstone, or white marble.<br />
3. Flesh-colored granite.<br />
4. Red granite.<br />
* Professor Hitchcock remarks that there is not a town in Massachusetts<br />
in which more or less granite does not occur, eiiher as situ or as boulders.
398 A POPULAR TREATISE ON GEMS.<br />
5. Epidotic granite.<br />
6. Porpbyritic granite.<br />
7. Chloritic granite.<br />
8. Sienitic granite.<br />
In Rhode Island a fine white granite has, according to<br />
Dr. Webb, of Providence, been employed fgr the erection<br />
of the arcade of that city, from a quarry in Johnstone, five<br />
miles from Providence.<br />
The manner in which granite is usually split out at the<br />
quarries, is this : a number of holes, of a quadrangular<br />
form, a little more than an inch wide and two or three<br />
inches deep, are drilled into the rock at intervals of a few<br />
inches, in the direction in which it is wished to separate<br />
the mass. Iron wedges, having cases of sheet iron, are<br />
then driven, at the same time and with equal force, into<br />
these cavities ;<br />
and so prodigious is the power thus exerted,<br />
that masses of ten, twenty, thirty, and even fifty and sixty<br />
feet long, and sometimes half as many wide, are separated.<br />
and it<br />
These may be subdivided in any direction desired ;<br />
is common to see masses thus split till their sides are less<br />
than a foot wide, and their length from ten to twenty feet.<br />
The price of the granite from these quarries, according<br />
to Professor Hitchcock, is from forty to forty-five cents per<br />
superficial foot, and for hammering and fine dressing it,<br />
about thirty cents the superficial foot, such as in the style<br />
of the Tremont House in Boston ; common work from<br />
twenty to thirty-five cents ; posts<br />
for stone fronts cost<br />
thirty-four cents per foot. The enterprising citizens of the<br />
city of New York have erected gigantic monuments of<br />
granite, for future generations to admire.<br />
New York abounds in granite, both east and west of the<br />
Hudson river, Staten Island, Westchester and Putnam<br />
counties. In the city of New York, a large bed of fine<br />
granite extends froin. Thirty-first street on the west side,
GRANITE. 399<br />
and from Twenty-fourth street in the middle, to Sixtieth<br />
street on the north. The Croton Aqueduct is mostly<br />
built of granite quarried in Tenth avenue near Forty-eighth<br />
street.<br />
Granite abounds in Rockland and Orange counties ;<br />
occurs in beds, veins, and irregular masses, forming hills,<br />
and often the tops of mountains.<br />
The fine-grained varieties of granite are best for eco-<br />
nomical uses. When granite contains distinct crystals of<br />
felspar, it is called porphyritic ; when the ingredients are<br />
blended into a finely granular mass, with imbedded crys-<br />
tals of quartz and mica, it is called by French writers,<br />
eurite. A granular mixture of quartz and felspar is called<br />
pegmatite.<br />
In England, Cornwall is particularly celebrated for its<br />
granite ; the obelisk from the Lamorran quarries, twentytwo<br />
feet high, which was exhibited at the London Exhi-<br />
bition, was twenty-one tons in weight, and of a coarse<br />
grain, and another, from Cornseco granite, weighing thirtyone<br />
tons, and" eighteen feet high, were beautiful specimens<br />
of this useful rock. They were each wrought from a single<br />
block of granite, and were remarkable for extreme fineness<br />
and closeness of grain, and the delicacy of finish which was<br />
thereby obtained.<br />
The granite column of Cheesewing granite, the property<br />
of the Prince of Wales, near Liskeard, in Cornwall, was<br />
likewise a magnificent piece. It was thirty feet high.<br />
The bust and pedestal of blue Peterhead granite was<br />
also an interesting specimen of its kind.<br />
Swedish granite has been known for many centuries ; it<br />
is obtained from extensive quarries on the island of Ma-<br />
leuva, on the west coast of Sweden. It bears a high polish<br />
it
400 .<br />
A<br />
POPULAR TREATISE ON GEMS.<br />
PEARLS.<br />
Pearls are concretions, consisting of carbonate of lime,<br />
having a roundish, tubercular, or angular form ; a white,<br />
gray, blue, or green color ;<br />
a shining lustre, and the hard-<br />
ness of lime; specific gravity, 2*68. They<br />
are found in<br />
several bivalve shells the meleagrina margaritifera, haliotis<br />
gigas, and haliotis iris, and a large species of turbo, which<br />
shells are known in commerce as flat shells, ear shells, green<br />
snail shells, buffalo shells, and Bombay shells ; many unios,<br />
alaniadontas, &c. Mother of pearl is the internal or nacreous<br />
layer of such shells. These precious substances are the<br />
result of an excretion in superimposed concentric laminae of<br />
a peculiarly fine and dense nacreous substance, which con-<br />
sists of membrane and carbonate of lime. The finest qual-<br />
ity is produced by the bivalve of the Indian seas, called par<br />
excellence the pearl oyster (meleagrina margaritifera}. In<br />
the United States the alasmadonta arcuata, corresponding<br />
with the mytilus margaritiferus of Barnes, the unio ochra-<br />
ceus, unio complanatus, and many other species, contain<br />
the pearls, and according to the nacre of the shells the<br />
color of the pearl is corresponding.<br />
The origin of pearls is by some considered to be unfructi-<br />
fied eggs ; by others, a morbid concretion or calculus,<br />
produced by<br />
the endeavor of the animal in the shell to fill<br />
up holes therein ; by others again,<br />
as mere concretions of<br />
the juice of which the shell has been formed, and with<br />
which the animal annually it. augments It is very plausible,<br />
however, that the animal of the shell is attacked often<br />
by enemies, such as the boring shells (turritella), &c. ;<br />
that<br />
grains of sand, or any other pointed substance, which, on<br />
such occasions, come within the shell, stick fast and augment<br />
with the growth of. the shell; it is also known that<br />
pearls may be produced artificially, by pressing a sharp
PEARLS. 401<br />
body on, or by boring a hole in, the shell. The Chinese<br />
are in the habit of laying a string with five or six small<br />
pearls separated by knots, inside of the shells, when the fish<br />
are exposing themselves to the sun, and taking them out<br />
after some years, whereby they obtain very fine and large<br />
pearls, and but a little open on the side where they were<br />
adherent to the shell. The pearl fishers say that when the<br />
shell is smooth and perfect, they never expect to find any<br />
pearls, but always do so when it has begun to be deformed<br />
and distorted. It was therefore concluded, that as the fish<br />
grew old, the vessels containing the juice for forming the<br />
shell and keeping it in vigor, became weak and ruptured,<br />
and from this juice accumulating in the fish, the pearl was<br />
formed, and the shell brought to decay, as supposed by M.<br />
Reaumur. It would be, according to this idea, a sure<br />
guide to know from the form of the shell, whether the<br />
pearl is large or small; and thus by the smaller ones being<br />
thrown back into the sea, a constant crop of large pearls<br />
might be obtained. The mother-of-pearl fish is found in<br />
the East and West Indies, and other seas in warm latitudes,<br />
and in the rivers of north and middle Europe. In some<br />
parts of the globe, they are found in clusters, containing a<br />
great number; the places where found are caUed pearlbanks.<br />
The most famous are near the coast of Ceylon,<br />
that of Japan, and in the Persian Gulf, near the island of<br />
Bahreim ; also near the coast of Java, Sumatra, &c. The<br />
finest and most costly pearls are called the Oriental, and<br />
are from the above places ; they are all white or yellowish ;<br />
those from, the Persian Gulf, on account of their perfect<br />
whiteness, are preferred to those from Ceylon. Pearls are<br />
collected in rivers with the hand, but in seas it is the busi-<br />
ness of divers, brought up to this most dangerous occupation<br />
from early youth. In the East Indies there are two<br />
seasons for pearl fishing ; the first in March and April, the
402 A POPULAR TREATISE (N GEMS.<br />
and the more rain, the<br />
second in August and September ;<br />
more productive are the pearl fisheries. In the beginning<br />
of the season there are sometimes two hundred and fifty<br />
the larger barks have two divers, the<br />
barks on the banks ;<br />
smaller, one. The divers descend from their barks with a<br />
rope round their body, and a stone of twenty or thirty<br />
pounds attached to one of their feet, so that they may sink<br />
speedily from eight to twelve fathoms, where they meet<br />
the shells fastened to the rocks ; the nostrils and ears are<br />
stuffed up with cotton, and to the arm a sponge dipped in<br />
oil is fastened, which the diver now and then brings to his<br />
mouth, in order to draw breath without swallowing water.<br />
He also carries down with him a large net, tied to his neck<br />
by a long cord,<br />
the other end of which is fastened to the<br />
side of the vessel, to hold the shells, and the cord is to<br />
draw him up when the net is full, or when he wants air ;<br />
he has likewise a knife or an iron rake, for detaching the<br />
the shells from the rocks. Thus equipped, he precipitates<br />
himself to the desired depth, where he can very distinctly<br />
see all that is passing around, yet cannot escape in time the<br />
sudden approach of sharks, to whom he too often becomes<br />
a prey. When the diver has been in water some minutes,<br />
and has his net filled, or is unable to stay any longer, he<br />
loosens quickly the stone at his foot, shakes the line, and<br />
he is drawn up by his companions. The diving-bell is now<br />
more so than in former years.<br />
frequently used ;<br />
In the Persian Gulf the divers rub their bodies with oil,<br />
and fasten a stone of about fifty pounds to their feet.<br />
The shells obtained are piled up in heaps, and left ex-<br />
posed to the rain and sun until the body of the animal<br />
putrefies, and they open of themselves. Those containing<br />
any pearls have from eight to twelve. After being picked<br />
out, washed, and dried, they are passed through nine sieves<br />
of different sizes.
PEARLS. 403<br />
At the Pearl Islands, near the Isthmus of Panama, the<br />
pearl fisheries have, within a few years past, become a<br />
lucrative business to many of the inhabitants. The clivers<br />
use more simple methods than those we have mentioned,<br />
for collecting the pearl oysters : they traverse the bay in<br />
canoes that hold eight men, all of whom dive naked into<br />
the water, from eight to ten fathoms deep, where they<br />
remain about two minutes, during which time they collect<br />
all they can with their hands, and dexterously rise to-<br />
deposit them in their canoe, repeating the operation for<br />
several hours.<br />
In Sweden, the pearl oyster is caught with a pair of<br />
long tongs. The fishermen are in small boats, painted<br />
white on the bottom, which reflects the light to a great<br />
depth, and as soon as they perceive them passing underneath<br />
they seize the oyster.<br />
Pearls are esteemed according to their size, form, color,<br />
and lustre ;<br />
the largest, of the size of a small walnut, are<br />
called paragons, which are very rare ; those the size of a<br />
cherry, are found more frequently, but still are rare ; they<br />
are the diadem or bead pearls. They receive names, also,<br />
according to their form, whether quite round, semi-circular,<br />
and drum-form, or that of an ear-drop, pear^ onion, or as<br />
they are otherwise irregularly shaped. The small pearls<br />
are called ounce pearls, on account of being sold by weight,<br />
and the very smallest, seed pearls. Those of a brilliant<br />
white color, or white water, are most sought for in Europe ;<br />
those of a yellowish color in some parts of Asia ;<br />
and some<br />
of a lead color, or those of a jt black, are preferred among<br />
some nations. They all turn more or less yellow with age,<br />
and to restore the white color, they are either baked in<br />
bread, rubbed with boiled salted rice, or kept for a short<br />
time in the gastric juice of fresh-killed chickens.<br />
Pearls are sold by weight troy weight j but the penny-
404 -A POPULAR TREATISE ON GEMS.<br />
weight of twenty-four grains is counted as thirty ;<br />
so that<br />
an ounce has six hundred grains, pearl weight, and four<br />
troy grains are equal to five pearl grains. The price<br />
has, within the last forty years, much diminished, for two<br />
reasons :<br />
1st. Diamonds, and particularly brilliants, have become<br />
more plentiful, and have since been worn, not by the higher<br />
classes alone, but also by the middling.<br />
2d. Within the last twenty years, artificial pearls have<br />
been manufactured in high perfection, and are worn to a<br />
great extent.<br />
It is my opinion, however, that the price of pearls will<br />
take a fresh rise among the nobility and richer classes,<br />
diamonds being now so generally worn ;<br />
as persons, think-<br />
ing to invest safely, without any future loss, their surplus<br />
capital, purchase brilliants that formerly were possessed<br />
exclusively by the rich.<br />
Pearl fisheries were first carried on in remote times in<br />
the Persian Gulf, and the most celebrated, formerly, were<br />
near the island Bahreim. Five hundred thousand ducats<br />
was then the yearly produce. About one million dollars'<br />
worth, at the present time, are exported. The island<br />
Kharack now produces the most considerable quantity.<br />
The principal market is at Muscat ; from thence they are<br />
brought to Surat. The mode of procuring them pursued<br />
in those countries, is in canoes, holding fifteen men, six of<br />
whom are divers: the shells caught during the day are<br />
delivered to a surveyor* when they are opened on a white<br />
cloth, and whoever finds a pearl of some value, puts it in<br />
his mouth, to give it, as they say, a " better water." The<br />
greatest harvests are generally after many rains, and the<br />
largest pearls are mostly found in the deepest water. At<br />
Ceylon the pearl fisheries are now considerable, particularly<br />
in the bay of Condatchy. The shells are there left to
PEARLS. 405<br />
reach the age of seven or eight years, and in the fourth<br />
year they have small pearls, sometimes a hundred and fifty.<br />
They fish yearly, in the month of May, during four weeks.<br />
In the year 1804, eight hundred canoes, each with two<br />
divers, were engaged. Before the year 1800, the pearl<br />
banks were leased, to an Indian merchant, for three hun-<br />
and before the arrival of the Euro-<br />
dred thousand pagods ;<br />
peans in India, the same bank was used every twenty or<br />
twenty-four years ; when under the Portuguese,.every ten,<br />
and under the Dutch, every six years. In 1800, the<br />
produce was from one hundred to one hundred and fifty<br />
thousand pounds sterling.<br />
Japan has some pearl banks, which are, however, not<br />
much sought ; the same may be said of the Nipthoa lake, in<br />
Chinese Tartary. America sent, in the sixteenth century,<br />
pearls to the amount of eight hundred thousand dollars to<br />
Europe. The shells were mostly collected from Cape Paria<br />
to Cape Velo ; round the islands Margarita, Cubagua,<br />
Coche Punta, Aragy, and at the mouth of Rio la Hacha,"<br />
from which latter locality, and the Bay of Panama, Europe<br />
is now mostly supplied. The former localities have long<br />
since been relinquished, on account of their small produce ;<br />
too many shells having been removed at one time, thereby<br />
retarding the growth of pearls. Panama has sent, within<br />
a few years past, about one hundred thousand dollars'<br />
worth of fine pearls to Europe, the trade being carried on<br />
of Panama. The coast of Florida is said<br />
by Messrs. Plise,<br />
to have been vefy lucrative to the Indians, as a pearl<br />
fishery, which, however, does not prove so now, since<br />
settlement of civilized people.<br />
the<br />
England used to be supplied from the river Con way, in<br />
Wales ; and Scotland supplied the London market, between<br />
the years 1761 and 1764, to the amount of ten thousand<br />
pounds sterling ; but the supply has failed. Pearls are
406 A POPULAR TREATISE ON GEMS.<br />
found in the Elster river, in the kingdom of Saxony, from<br />
its source at the borders of Bohemia to Elsterberg, where<br />
the fishery has been jcarried on since 1(521, with some ad-<br />
vantage to the sovereign ; some pearls found there were<br />
valued at fifty Prussian dollars each. In the river Watawa,<br />
in Bohemia, and in the Moldau river, from Kruman to<br />
Frauenburg, pearls are found of great beauty;<br />
so much so<br />
as to equal in price the Oriental pearls. Also, at Rosenberg,<br />
pearls are* sometimes found superior to the Oriental in<br />
and at Oelsnitz, a considerable pearl fishery is car-<br />
lustre ;<br />
ried on. Most of the rivers in Sweden, Lapland, Finland,<br />
Poland, Norway, Jutland, Silesia, and other places, contain<br />
pearls, but they are not collected.<br />
It is a "fact that the pearl is equally hard throughout all<br />
. its concretional layers, for by putting the pearl in a weak<br />
acid, the outside layer becomes gelatinous, arid the succeeding<br />
layers are found to be equally hard and uniform.<br />
It is almost impossible, therefore, that the story told of<br />
Cleopatra having swallowed a pearl after being dissolved<br />
in vinegar, should be true ; besides, if the pearl had been<br />
dissolved as quickly as reported, it would not have made<br />
a very disagreeable beverage. Pearls were known, and<br />
were very much esteemed by the Greeks and Romans, and<br />
when they became acquainted with the Indies, by com-<br />
mercial intercourse and conquest, they preferred the pearls<br />
of the East to those that were obtained from the rivers of<br />
Europe, or even from the Mediterranean.<br />
With the ancients the wearing of this species of curiosity<br />
became a passion and even a folly. Necklaces, bracelets,<br />
and ear-rings were then worn in profusion ; dresses, head<br />
and foot ornaments were manufactured with pearls.<br />
Mil-<br />
lions of sesterces (a Roman coin of two hundred francs<br />
value), were expended and lavished for the best and most<br />
extraordinary pearls. The two pearls of Cleopatra cost
PEARLS.<br />
407<br />
nearly two millions of francs ; Julius Caesar presented to<br />
Servilia, the sister of the celebrated Cato, of Utica, a pearl<br />
which he purchased for one million two hundred thousand<br />
francs-.<br />
Lollia Paulina, the wife of Caligula, wore ornaments to<br />
the value of eight millions of francs. The ladies went so<br />
far as to ornament their buskins with pearls. Nero lav-<br />
ished pearls upon his lewd women. In modern times<br />
Buckingham distributed in the halls of the Empress Ann,<br />
of Austria, and of King Louis XIII., pearls to the value of<br />
three hundred thousand francs.<br />
The baroques, which are excrescences in the mother of<br />
pearl, are sometimes very large, and display some extraordinary<br />
figures and inconceivable freaks of nature. They<br />
are held in high estimation, and are mostly worn in Spain<br />
and Poland.<br />
Caire, the celebrated French jeweller, possesses many<br />
baroques ; one representing a bearded dog ;<br />
"<br />
another, rep-<br />
resenting the order of the fleece. He had a mother of<br />
pearl containing a large excrescence, representing a Chinese<br />
with crossed legs.<br />
The prices of pearls, from one carat upwards, were for-<br />
viz : if the carat<br />
merly determined like those of diamonds,<br />
b fixed at five dollars, and a pearl weighs four carats, take<br />
the square, or sixteen, which multiplied by five is equal to<br />
eighty; so that a pearl<br />
of four carats was estimated at<br />
eighty dollars.<br />
At present the following are the prices of pearls :<br />
1 grain is worth, in France, 4 francs per carat.<br />
it "<br />
9 K c<br />
|0<br />
3<br />
" " " 25<br />
" u<br />
4<br />
"<br />
(1 carat)<br />
"<br />
50<br />
" "<br />
The baroque pearls are sold at from three hundred to<br />
one thousand francs per ounce.
408 A POPULAR TREATISE ON GEMS.<br />
The seed pearls, when quite round, are worth about one<br />
hundred and twenty francs per ounce.<br />
In France, perforated pearls are valued at twice the<br />
prices given above. The piercing of the pearl is well understood<br />
in the Indies. The value of a pearl is always<br />
those that have a<br />
enhanced by size, perfection, and color ;<br />
yellowish-white, or silver-white, or very pale gold-yellow<br />
shade, or a rose or lilac color, are the most esteemed<br />
pearls.<br />
The French pearl fisheries produce at least from three to<br />
four millions of franco.<br />
The French Crown possesses pearls of immense value :<br />
One round virgin pearl, of a magnificent orient, weighing,<br />
5<br />
27T g- carats, is valued at two hundred thousand francs. Two<br />
pear-shaped pearls, well formed, of a beautiful orient, and<br />
weighing together 57y^ carats, are valued at three hundred<br />
thousand francs;<br />
6<br />
two ear-drops, weighing 99T^ carats, are<br />
valued at sixty-four thousand francs.<br />
About seventy-two more large pearls, of great beauty<br />
and exquisite form, pear-shaped and round, valued in the<br />
aggregate sum of three hundred and fifty thousand francs.<br />
At the Paris Exhibition, in 1855, an enormous pearl, of<br />
pear-shape, brought from Berlin, by Napoleon I., was<br />
exhibited.<br />
The Princess Royal of England, at her marriage to<br />
Prince Frederic William, of Prussia, .wore a necklace of<br />
the finest pearls, which cost, at the least calculation, five<br />
hundred thousand francs.<br />
The Emperor Rudolph possessed a pearl weighing one<br />
hundred and twenty grains.<br />
King Philip II., of Spain, possessed a pear-shaped pearl<br />
of the size of a pigeon's egg, weighing one hundred and<br />
thirty-four grains. It came from Panama, and was valued<br />
at fifty thousand ducats. It was called the Peregrina.
PEAKLS.<br />
409<br />
In 1620, King Philip IV., of Spain, purchased a pearehaped<br />
pearl from Gougitas, of Calais, which weighed four<br />
hundred and eighty grains. An anecdote is told of the<br />
King, who asked the merchant how he could risk his whole<br />
fortune in so small a piece as that pearl ; whereupon the<br />
merchant replied, that he knew there was one king of<br />
Spain in the world who could afford to it. purchase It<br />
now belongs to the Princess Youssopoff.<br />
A costly collection of pearls from the Indies, Ceylon,<br />
and Singapore, and innumerable pieces of ornamental jewelry<br />
set with most costly pearls, was exhibited at the London<br />
Exhibition by Messrs. Garrard, Hunt, Roskell, and<br />
other jewellers.<br />
A large pearl, from Vermont, United States, weighing<br />
eleven carats, and very round, but not of bright color, is<br />
in the possession of Mr. S. H. Palmer.<br />
Messrs. Blogg & Martin, of London, inform me, under<br />
date of April 25, 1859, that they have in their possession a<br />
magnificent pearl necklace, consisting of thirty-seven perfect<br />
pearls, of forty grains each ; they sent a description of<br />
it, and also of two beautiful pearl-drops, which they value<br />
at two thousand pounds sterling. The necklace and drops,<br />
which must be unique specimens, deserve more than "a<br />
mere notice, but the description came too late for insertion.<br />
United States Pearls.<br />
New Jersey merits the credit of producing fine pearls ;<br />
a great many thousand pearls have been obtained from the<br />
mussels, which compare fairly with those of the India pearlshell<br />
; size, color, nacre, and orient are displayed in many<br />
of the New Jersey pearls in a high degree, and are now<br />
passing in Europe for the genuine<br />
Oriental or Panama<br />
pearls. In 1857, a shoemaker named David How ell, living<br />
18
410<br />
A POPULAR TREATISE ON GEMS.<br />
Fig. 14.
Fig. 15.<br />
PEAHLS. 411<br />
Fig. 12 J.<br />
Fig. 16.
412 A POPULAR TREATISE ON GEMS.<br />
near the town of Paterson, New Jersey, went to a neighboring<br />
brook, called Notch brook, in order to collect some<br />
mussels for his breakfast, and, on opening them, discovered<br />
a great many loose pearls falling out, which he took to a<br />
jeweller in Paterson, who stated to him that they were<br />
valuable, and they both began to collect millions of these<br />
mussels, and their efforts were crowned with success. The<br />
preceding representation of the mussel belongs to the great<br />
family of unio, which was formerly called the avicula mar<br />
garitifera, mya margaritifera, but now known as an alasmadonta<br />
arcuata named by Barnes. Many unios (of<br />
which there are, according to Lea, Say, and other Ameri-<br />
can conchologists, over six hundred species), contain pearls<br />
more or less and Mr. John H. ; Redfield, the efficient<br />
corresponding secretary of the New York Lyceum of<br />
Natural History, informs me that he found the pearls in<br />
the same locality in New Jersey, in three or four other<br />
unios, such as the unio complanatus, unio ochraceus, unio<br />
radiatus, &c. A very perfect pearl in the shell may be<br />
seen in the annexed drawing, which is copied from " Frank<br />
Leslie's Illustrated News" of May, 1857; the pearl is rather<br />
dark, and the shell, as may be seen, appears worn off.<br />
This is one of the characteristics of the shells containing<br />
pearls, and it appears to indicate that the animal is in the<br />
decline of life, and that the mussel is becoming gradually<br />
decayed.<br />
The streams in which these pearl shells are found are<br />
generally very shallow, not more than one or two feet<br />
deep, and the shells may be picked up with the hands;<br />
many thousand shells are opened, containing deposits of<br />
the pearly matter, most of which contains shapeless and<br />
colorless pearls^ which are so small that they -are of no<br />
value ; many, however, contain very perfect pearls ; the<br />
crown-pearl, weighing ninety-one grains, in the possession
PEARLS. 413<br />
of Messrs. Tiffany & Co., was purchased from Mr. Howell<br />
for $1500. This pearl resembles a crown, having three<br />
smaller pearls resting upon the large pearl ;<br />
another repre-<br />
sentation of a pearl weighing nearly four hundred grains,<br />
here represented, was destroyed by cooking the mussel in.<br />
order to open it better, and the color of the nacre has<br />
been spoiled ; it would, probably, have been the largest<br />
pearl of modern times, and of immense value.<br />
The alasmadonta of the present day was formerly called<br />
mya, from the Greek fiva), to compress, it is called in<br />
English, the gaper, on account of the bivalve gaping at one<br />
end, its hinge having a solid, thick, patulous tooth, seldom<br />
two, and not inserted in the opposite valve; the same<br />
genus was originally called mytilus; they inhabit both<br />
the ocean and fresh<br />
mud at the bottom.<br />
water; they perforate the sand or<br />
Many species are caught for food,<br />
and others for the pearls; some few of the same genus<br />
perforate and live in limestone, like the pholadites.<br />
The pearl-bearing mya, now alasmadonta, is frequently<br />
found in the large rivers of northern latitudes. The Brit-<br />
ish Islands, especially Ireland, were formerly famous for<br />
their fisheries, and a few pearls of great value have at times<br />
been obtained from these sources, although<br />
the British<br />
specimens are not held in high estimation, with the exception<br />
of a few procured from, the river Shannon, in the<br />
year 1821.<br />
The river Irt, in Cumberland, the Conway, in Wales,<br />
and the Tay, in Scotland, were once noted for their pearl<br />
fisheries. Suetonius reports that Caesar was induced to<br />
undertake his British expedition for the sake of the pearls ;<br />
and according to Pliny and Tacitus, he brought home a<br />
buckler made with British pearls, which he dedicated to,<br />
and hung up in the temple of the idol Venus genetrix.<br />
The gapers are mostly used for food, both in Britain
414 A POPULAR TREATISE ON GEMS.<br />
and on the Continent ; around Southampton, in England,<br />
these mussels are known by the whimsical name of " old<br />
maids," and the inhabitants of the northern islands call<br />
them smuslin, and consider it a fine supper-dish, which is<br />
by no means unpalatable.*<br />
I am informed by Mr. Plise, who brought a considera-<br />
ble quantity of pearls from Panama, that he receives four<br />
dollars per grain in England, for those of good size and<br />
quality.<br />
Pope Leo bought a pearl for eighty thousand crowns.<br />
Tavernier describes one belonging to the King of Persia,<br />
which is said to have cost one million six hundred thousand<br />
livres. Portugal has a pearl in her treasury of the size of<br />
a pear. Two Greeks, residing in Moscow, are in posses-<br />
sion of a pearl weighing twenty-seven and seven eighths<br />
carats.<br />
For restoring Oriental pearls to their original lustre,<br />
which they lose in the course of time, the following process<br />
is resorted to in Ceylon : the pearls are allowed to be<br />
swallowed by chickens, which are then killed, and the<br />
pearls are an hour afterwards taken out of the stomach,<br />
when they are as white and as lustry as if just taken from<br />
the shell.<br />
The poet Cowper thus expatiates on the mussel:<br />
" Condemn'd to dwell<br />
Forever in his native cell ;<br />
Ordain'd to move where others please,<br />
Not for his own content or ease ;<br />
But toss'd and buffeted about,<br />
Now in the water and now out ;<br />
Yet in his grotto-work inclosed<br />
He nothing feels in that rough coat,<br />
Save when the knife is at his throat;<br />
Wherever driven by wind or tide,<br />
Exempt from every<br />
ill beside."
PEAELS. 415<br />
Artificial Pearls.<br />
Artificial pearls or beads are of various kinds; most<br />
generally they consist of solid masses of glass, with a hole<br />
or they are blown hollow, and then filled<br />
drilled in them ;<br />
out with metallic lustry grains, wax, or with the fine scales<br />
of the bleak fish, which have a silvery and pearly lustre.<br />
The art of imitating pearls is attributed to a manufac-<br />
turer of beads, of the name of Janin or Jalquin, who lived<br />
at Paris in 1680; he was led to the discovery by seeing,<br />
one day, the scales of the bleak fish swimming in a trough,<br />
where the fish detached them by rubbing against each<br />
other, and he at once conceived the idea of applying these<br />
scales for imitating the orient of the pearls, by mixing<br />
them with a mucilage and filling the interior of hollow<br />
glass bulbs, and he gave this natural and wonderful production<br />
the name of Extract of Orient a very singular<br />
name, but still significant of the meaning of its employment.<br />
It is well known that this little white fish, the bleak, is<br />
found in abundance in the rivers Seine and Marne, in<br />
France, and in many small rivers in Sweden, Germany,<br />
and Italy. The bleak fish fructifies around water-mills,<br />
where they are caught by nets.<br />
For the purpose of extracting the color of the scales of<br />
the fish, they are rubbed pretty hard in the fresh water<br />
collected in a stone basin, which settles down in the bottom<br />
of this vessel ; the sediment is then pressed out through<br />
a linen rag, and they are then replaced again in fresh<br />
water and left there to settle for several days, when the<br />
water is drawn off and the precipitate is carefully collected ;<br />
this is called the extract or essence, and it requires from<br />
seventeen to eighteen thousand fishes to obtain five hun<br />
dred grammes (a little over one pound).<br />
The scales being animal matter are, therefore, liable to
416 A POPULAR TREATISE ON GEMS.<br />
decomposition, and for their preservation numerous chemical<br />
agents have been employed by the different manufac-<br />
turers, all of whom, who have succeeded, keep it a secret ;<br />
it is, however, known that liquid ammonia is added to the<br />
paste of the scales. .<br />
The operation of the manufacture is very difficult, but<br />
an experienced workman can manufacture six thousand<br />
pearls in a day.<br />
The chemists have experimented for some years to imi-<br />
tate the extract of orient, as it requires such a large<br />
and<br />
quantity of fishes to obtain any amount of the scales,<br />
according to Mr. Barbot, the following preparation has<br />
produced a favorable result : which is by distilling one part<br />
of oxide of bismuth and two parts of corrosive sublimate ;<br />
the product is a species of butter, which on redistilling<br />
yields metallic quicksilver and a very fine powder ;<br />
this is<br />
the substance used for orientalizing or coating the artificial<br />
pearls with the true gloss- of an Oriental pearl.<br />
The same scales are likewise used to coat beads of gypsum,<br />
or alabaster, which are soaked in oil and then covered<br />
with wax to give them a pearly appearance. The Roman<br />
beads are made in this manner : the scales are dissolved<br />
either in liquid ammonia,- or vinegar, and the solution or<br />
liquid is used for covering those artificial beads. The Turkish<br />
rose-beads are made of an odoriferous paste, and are<br />
turned afterwards like those of coral, amber, agate, or<br />
other hard substances. The knitting beads are sold in<br />
meshes of one hundred and fifty, or twenty strings, of<br />
fifty beads each, of various colors ; and the large glassbeads<br />
in meshes of twelve strings. There are numerous<br />
manufactories in Germany and Italy of the various kinds<br />
of beads, which are used to a very great extent both in<br />
Africa and North and South America. Germany exports<br />
yearly from its different manufacturing places, such as
PEARLS. 417<br />
Heidelberg, Nuremberg, Sonnenberg, Meistersdorf, in Bohemia,<br />
and Mayence, more than a million dollars' worth.<br />
In Venice are large establishments for the finest cut beads.<br />
Nuremberg manufactures, besides glass beads, considerable<br />
quantities of amber beads. In Gablontz, in Bohe-<br />
mia, more than six thousand persons are engaged in the<br />
manufacture of beads, that are made of pure glass, or of a<br />
composition. From the glass-houses, which are very<br />
numerous in Bohemia, the rods of different sizes are<br />
delivered to the glass mills for cutting, which is performed<br />
by water power or by hand. In 1828 there were in that<br />
neighborhood one hundred and fifty-two mills in operation;<br />
a number of glass-blowers were likewise engaged, who<br />
possessed great dexterity in blowing the small beads with<br />
the assistance of a small blow-table. In the manufactory of<br />
George Benedict Barbaria, at Venice, six hundred varieties<br />
and that of Messrs. Gas-<br />
of beads are constantly making ;<br />
pari and Moravia manufactures, besides the beads, every<br />
article of jewelry from the same material.<br />
The rose beads of Steffansky and Tausig, are made of<br />
bread crumbs, which are beaten up with rose water in a<br />
wooden mortar, until they become a uniform mass, to<br />
which is added some otto of roses and drop-lake, when it is<br />
made into beads with dissolved gum tragacanth ; for the .<br />
black rose-beads, Frankford black is substituted hi the<br />
place of the drop-lake.<br />
Lamaire, of France, manufactures beatfs equal in lustre<br />
and beauty to real pearls. He adds to<br />
1000 ounces of glass beads,<br />
3<br />
^<br />
1<br />
"<br />
"<br />
"<br />
scales of the bleak-fish,<br />
fine parchment glue,<br />
white wax,<br />
1<br />
"<br />
pulverized alabaster,<br />
with which he gives them an external coating.<br />
18
418 A POPULAR TREATISE ON GEMS.<br />
Rouyer manufactures his beads, also in France, from<br />
opal, which he covers with four or five layers of dissolved<br />
isinglass, and then with a mixture of a fat oil, spirits of<br />
turpentine, and copal, so as to prevent their becoming<br />
moist. In order to render them of the peculiar lustre of<br />
the Oriental pearls, they are covered with a colored enamel.<br />
The opal is fused into rods by a lamp, over which is laid a<br />
brass wire to support it ;<br />
the wire is held in one hand and<br />
the opal in the other, and the wire is then kept turning<br />
until the bead has the desired size and .roundness; if a<br />
colored enamel is to be applied, the beads are made but<br />
half the required size, which being done, they are once<br />
more covered with the opal, then the solution of isinglass<br />
is used, and lastly the varnish. Beads made in this man-<br />
ner are with difficulty distinguished from the Oriental<br />
pearls.<br />
The best method of making artificial<br />
pearls, is certainly<br />
by means of pulverized real pearls. Either the smallest, or<br />
the deformed large specimens, may be reduced to a fine<br />
powder, and then soaked in vinegar or lemon-juice, and<br />
the paste made up with gum tragacanth ; they may then be<br />
cut out with a pill machine, or a silver mould, of any desired<br />
size, and when a little dry, inclosed in a loaf and baked in<br />
an oven : by tin amalgam, or by the silver of the scales of<br />
young fish, the proper lustre may be given.<br />
The artificial pearls, by Constant Vales & E. Truchy, of<br />
Paris, which were on exhibition in the London Crystal<br />
Palace, were extremely beautiful, and were with the<br />
greatest difficulty distinguished from the natural pearls.<br />
Messrs. Bouillette, Hyvelei & Co., of Paris, exhibited,<br />
besides many beautiful pearls, a great variety of artificial<br />
stones, all of their own manufacture, and very tastefully<br />
set ; among them was a stomacher in diamonds, pearls, and<br />
emeralds.
CORALS. 419<br />
The shad-fish, as well as the white-fish of our lakes, must<br />
yield an extract of orient, of as good a quality as the bleak-<br />
fish of the Seine, and it is to be hoped that some enter-<br />
prising mechanic may take an opportunity of preparing the<br />
white matter adhering to the scales of the fish just men-<br />
tioned, either for export, or for the purpose of imitating<br />
pearls, which may be done as well in this country as anywhere<br />
else.<br />
The usual price of false pearls is two dollars and fifty<br />
cents a string, one hundred to the string ; but some are<br />
lower, and some higher, according to color.<br />
CORALS.<br />
Corals are zoophytes, whose calcareous habitations resem-<br />
ble vegetable branches. They live in the sea, adhering to<br />
rocks, stones, or vegetables, and shoot to the surface of the<br />
water in tnbiform stems with branches, generally coated<br />
with a gelatinous or leathery skin that incloses a cartilaginous<br />
marrow, composed of many cells, inhabited by the<br />
animals, who propagate in sprouts from eggs so fast, that<br />
small reef-rocks are formed, which in the course of time<br />
become islands.<br />
The red coral, or precious coral (iris nobilis), belongs to<br />
that family of zoophytes which live mostly in the cavities<br />
of rocks in the sea ; the stem is always of a beautiful red<br />
color, rarely white ; quite compact, striated on the outside,<br />
of entire calcareous composition ; it grows one foot high<br />
and an inch thick. The stem is covered with a leathery<br />
crust, containing open warts of eight teeth, in which the<br />
animals, or polypi, with their eight arms, are situated ;<br />
the<br />
arms are whimpered, and the animal grows very slowly.<br />
The red coral is fished up with nets of strong ropes, fas-<br />
tened on large wooden cross-beams, which are thrown
420 A POPULAR TREATISE ON GEMS.<br />
down on the places where the corals are known to be fas-<br />
tened, and an expert diver contrives to entangle the nets<br />
in the reefs, which are then drawn up by force. The corals<br />
so brought up are cleaned, assorted, and sold to the manu-<br />
facturers.<br />
Messrs. Payenne & Laminal have invented a very ingenious<br />
machine for collecting the coral from the banks of<br />
the ocean, without breaking the fine branches and without<br />
injuring the banks which are formed for the growth of the<br />
coral.<br />
It is a fact admitted by naturalists and fishermen, that<br />
the growth and accumulation of the zoophytes take place<br />
continually in the same waters ; and that as great and pro-<br />
the fish-<br />
lific a traffic may be created by coral catching as by<br />
eries in France. Lord Ellis proved, in 1754, that the coral<br />
polype possesses an ovarium filled with small eggs, pre-<br />
pared for hatching ; all these eggs are attached together<br />
by a species of cordon, and resemble worms ; tentacles are<br />
shooting out from them, which move in the same manner<br />
a$ the grown polypes.<br />
In 3856, Mr. Focillon presented a report to the Acclimi-<br />
tation Society at Paris, on the methodical exploration of<br />
the ancient and natural banks, and on the construction of<br />
artificial coral banks in such a manner as to secure the<br />
most favorable position for the production and operation<br />
of an easy and sure coral harvest. Facts have already<br />
been elicited, that the new coral succeeds so well at a<br />
depth of seven to eight metres (twenty four feet), under<br />
the influence of the rays of the sun, that it develops quickly,<br />
and becomes large and of good color at the end of eight or<br />
nine years; while a coral at a depth of thirty to fifty<br />
metres (one hundred and fifty feet), requires from thirty-<br />
five to forty years to shoot out, and it is not then of as<br />
good a color as the former. This discovery ought to
COEALS. 421<br />
stimulate the African coast (Algeria), particularly the in<br />
habitants on the shores of Bona, Oran, and other places,<br />
who ought to be beforehand in the application ; also on the<br />
Marseilles coast, which is already full of coral reefs. .<br />
Coral was formerly cut in facets, and was in great favor<br />
under the consulate and empire of France, for almost every<br />
species of luxury ; combs, ear-rings, necklaces, beads,<br />
but<br />
crosses, &c., were manufactured and sold at high prices ;<br />
the fashion and price soon fell. Ten or fifteen years after-<br />
wards an endeavor was made to bring coral in vogue again,<br />
by offering coral engraved as cameo, and made into other<br />
ornaments, such as brooches, bracelets, ear-rings, and pins,<br />
which were then sold pretty high ; but on account of an<br />
insufficient supply of the article and bad workmanship, it<br />
fell back to its original lethargy, and for many years it was<br />
considered worthless and altogether out of fashion.<br />
During the last two years, coral has resuscitated very<br />
much, and got into good grace with the ladies.<br />
The Parisians have, however, changed their taste for the<br />
former favorite, the red coral ; the rose-colored, cut in a<br />
round form, so as to nearly resemble a rose pearl, being<br />
preferred, which is acknowledged to be extremely rare.<br />
The price of these rose'-colored corals has of late risen so<br />
high, that a fabulous sum is paid for them; and a coral<br />
which was worth but fifty francs in 1810, is now sold for<br />
three hundred francs and upwards. At present the fashion<br />
for corals is at its height, and ornaments of every con-<br />
ceivable variety may be seen in the shops of jewellers in<br />
this country, imported from France and Italy. .<br />
At the last Paris Exhibition there was a coral chess-<br />
board, with all its figures representing an army of Crusaders<br />
and of Saracens, which was admirably executed, and<br />
valued at 10,000 francs. Coral branches, if. without a frac-<br />
ture, bring a great price.
422 A POPULAR TREATISE ON GEMS.<br />
France manufactures and exports coral ornaments to the<br />
value of six millions of francs, and the demand for them<br />
is much greater; the establishments of Barbaroux and<br />
Garaudy & Fils, in Marseilles, where the coral is<br />
principallymanufactured<br />
into ornaments, give proof that France will<br />
retain the supremacy in this species of luxury.<br />
In the Paris Exhibition of 1855, many curious sculptured<br />
and chiselled objects were shown by Arsene Gourdin, of<br />
Paris.<br />
In the London Exhibition, fine corals were shown from<br />
the Cape of Good Hope, from Reftaelli & Son, in Tuscany;<br />
from Algiers .was also a collection. Tucker & Co., of Ber-<br />
muda, exhibited a fine collection of both corals and madre-<br />
pores, including the black flexible coral (gorgonia).<br />
Among the ancient rare coral engravings is the head of<br />
the philosopher, Chrysippe, in high relief: it was in the<br />
Orleans collection. A coral cameo of the 14th or 15th<br />
century, representing a Sphinx with three Cupids, well<br />
executed, is mentioned by Caire.<br />
The red corals are distinguished by the names of the<br />
countries where found.<br />
1. The Barbarian, which are the thickest and purest.<br />
2. The Corsican, which are the 'darkest, but not so thick,<br />
and less pure.<br />
3. The Neapolitan, and those from Ponza, which are<br />
clear and pretty thick.<br />
4. The Sardinian, which are thick and clear.<br />
5. The Catalonian, which are nearly as dark as the Cor-<br />
sican, but mostly thin.<br />
6. The Trapanian corals, from Trapani, in Sicily, which<br />
are somewhat preferred at Leghorn.<br />
The darkest corals are most liable to be worm-eaten.<br />
The polished corals are generally sold in bundles, which<br />
consist of a certain quantity of strings, of a certain weight.
CORALS. 423<br />
They are strung in Leghorn, either of various or equal<br />
thicknesses, which latter are then of various sizes, and the<br />
bundles receive their names accordingly; grossezze, mez-<br />
zanie, filotti, capiresti, &c. The thickest corals are put<br />
up in one string, resembling a tail, and are called codini ;<br />
the smallest are called smezzati.<br />
At Genoa, the various large corals are called mezza-<br />
nie j the uniform large, filze / and the uniform small,<br />
migUari.<br />
They are distinguished according to color at Leghorn ;<br />
the darkest red are called arcispiuma, Avhich are the dearest ;<br />
and then primo, secundo, terzo, quarto, coloro or sangue,<br />
chiari, moro, nero, &c.<br />
According to form they are called round (tondi), and<br />
cylindrical-round (boticelli). The former are sent to all<br />
parts of the world, but the latter are only sent to Poland.<br />
The large boticelli are put up in meshes of twelve pounds,<br />
and the middling size of the<br />
containing thirty-six strings ;<br />
boticelli are in meshes of six pounds, containing sixty<br />
strings; those boticelli which are still larger, are called<br />
olivatti, and are only sent to Africa ; those which are globular,<br />
and not drilled, are called paUini altorni, and sent<br />
principally to China, where the favorite color is the rose-<br />
red.<br />
The sound corals are called netti, and the worm-eaten,<br />
camolatti, which latter are mostly sent to the East Indies.<br />
The tops of the branches are called dog-teeth, or dents<br />
canines, and the thick ends of the branches are called mao-<br />
metti both kinds are perforated lengthwise, and are used<br />
in Barbary as ornaments for horses. The fine large coral<br />
stems which form suitable specimens for cabinets of natural<br />
history, in Marseilles, are called chouettes.<br />
There are one hundred varieties of shades of red coral<br />
distinguished at Marseilles.
424 A POPULAR TREATISE ON GEMS.<br />
Corals are principally used for ornaments, in the East<br />
Indies, China, and Africa, where they are preferred to the<br />
diamond. Almost every East India lady wears a bracelet<br />
or necklace of corals.<br />
The white coral has its origin from the eight-star coral<br />
(rtiadrepora occulta)] and the black coral from the black-<br />
horned coral (gorgonia antipotlies) . The medusa head<br />
(caput medusce), called the sea polen, belongs likewise to<br />
the coral family, and consists of sixty-two thousand six hun-<br />
dred and sixty-six articulated members.<br />
Corals are fished for on the coast of Barbary, between<br />
Tunis and Algiers ;<br />
in the latter state Bona is the principal<br />
the French have one also at Basteon de France.<br />
The monopoly was purchased by France, in the seven-<br />
station ;<br />
teenth century, at eighteen thousand dollars annually; and<br />
by England, since 1806, for fifty thousand dollars.<br />
At Bona there is a summer fishery, from the first of<br />
April to the first of October, which occupied, in 1821,<br />
thirty French, seventy Sardinian, thirty-nine Tuscanian,<br />
eighty-three Neapolitan, nineteen Sicilian barks ; alto-<br />
gether, two hundred barks of two thousand and twentythree<br />
tons capacity, with two thousand two hundred and<br />
seventy-four men ; they fished up forty-four thousand two<br />
hundred pounds of coral, valued at two million four hun-<br />
dred thousand francs. The winter fishery of the same year<br />
occupied three French barks, each with nine men, and they<br />
obtained six hundred and eighty pounds of coral.<br />
The principal manufactories of corals are now at Leghorn,<br />
where this branch of business has been carried on for<br />
two hundred years past, by the Jews. There were for-<br />
merly twenty establishments, but the number has lately<br />
been much diminished.<br />
They are sent principally to China, the East Indies, and<br />
Arabia, partly by the way of London, and partly by Mos-
SHELL CAMEOS. 425<br />
cow, Aleppo, and Alexandria; many corals are likewise<br />
sent to Poland.<br />
Genoa has a few manufactories, in which the Sardinian<br />
corals are mostly wrought. At Marseilles there has been<br />
a large manufactory ever since 1780, and at present it is<br />
the only establishment of the kind in France.<br />
The East Indies consume, according to the statement of<br />
Le Goux de Haix, nearly four million francs' worth.<br />
Corals are worn in the East as ornaments in the turban,<br />
and the Arabs bury the coral with their dead.<br />
A large coral, from the manufactory at Marseilles, was<br />
sold in China, to a mandarin, for twenty thousand dollars.<br />
Purpurin is the name of artificial coral. A large quantity<br />
of this false and base imitation of coral has been im-<br />
ported into this country. It is used for setting in cheap<br />
jewelry; brooches, bracelets, ear-rings, and pins may be<br />
seen everywhere in this city, all carved in figures and ani-<br />
mals, resembling the true coral, but on testing it with a<br />
knife, the baseness is easily detected. It is composed of<br />
marble powder, made into a paste by a very siccative oil<br />
or varnish, or soluble glass (silicate of potash), and a little<br />
isinglass, and colored by Chinese vermilion. The paste<br />
is then moulded into the various objects required, and when<br />
dry such parts as require it are perfected with the chisel.<br />
SHELL CAMEOS.<br />
The shells employed for cameo-cutting, .are the cassis<br />
rufa, and several species of cyprea, called cowries. They<br />
are dense, thick, and consist of three layers of differently<br />
colored shell material. In the cassis rufa, each layer is<br />
composed of many very thin plates, or lamina?, which are<br />
perpendicular to the plane of the main layer ;<br />
each lamina<br />
consists of a series of elongated prismatic cells, adherent by
426 A POPULAR TREATISE ON GEMS.<br />
their long sides ; the laminae of the outer and inner layers<br />
are parallel to the lines of growth, while those of the<br />
middle layer are at right angles to them. In cowries<br />
there is an additional layer, which is a duplicature of the<br />
nacreous layer, formed when the animal has attained its<br />
full growth.<br />
At the London Exhibition there was a very fine collec-<br />
tion of shell cameos, from Rome, owned by the engraver<br />
Seculine.<br />
Certain natives of India prepare shell cameos with rude<br />
but efficient instruments for cutting them, and the Indian<br />
department in the Exhibition showed numerous specimens.<br />
MOSAIC AND PIETRA DURA.<br />
Roman, Venetian, Florentine, and other Mosaics.<br />
The art of mosaic (opus musivum of the Romans), was origi-<br />
nally applied only to the combination of small dice-shaped<br />
stones (precious and common), or tessera? of the ancients,<br />
in patterns.<br />
It has long been an important source of labor<br />
to the inhabitants of several parts of Italy, such as Venice ;<br />
and under various modifications is now carried on in the<br />
principal cities of Europe. The manufacture has long<br />
ceased to be confined to combinations of tessera?, and is<br />
now understood to include all kinds of inlaid and veneered<br />
work, in whatever material, fragments of pseudo-precious<br />
stones (agate, chalcedony, malachite, lapis lazuli), marbles<br />
of the most variegated colors, porphyry, lava, granite,<br />
fluor-spar, and also the various colored glasses (imitation<br />
gems), avanturine, and enamels, which, when put together<br />
(sometimes in microscopical fragments), and formed into a<br />
landscape, figures, or other design, are now called mosaics.<br />
The richer the colors and shadings, so as to produce fine<br />
pictures, the more striking the mosaics fall on the eye of
MOSAIC AND PIETBA DURA. 427<br />
the spectator. The Roman mosaics, in which prisms or<br />
threads of glass, of various sizes and shapes, compose the<br />
whole picture ;<br />
the Venetian mosaics, where the glass is a<br />
tessera or square shape, of some size, inlaid often in a<br />
cement base.<br />
The manufacture of true Roman mosaics has always<br />
been confined to the city whence its name is taken, and no<br />
country has entered into competition with Rome. They<br />
are composed of glass, sometimes called smalt, and some-<br />
times paste ; are made of all kinds of colors and every<br />
different hue. For large pictures they take the form of<br />
small cakes ; for small works they are produced in threads,<br />
varying in thickness from that of a piece of string<br />
to the<br />
finest cotton thread : large quantities of these, of all tints<br />
and colors, are prepared. A plate or slab of copper, marble,<br />
or slate is then provided, of the size and thickness required<br />
for the intended work. This slab is hollowed out so as to<br />
resemble the bottom of a box or a tray, to a depth proportioned<br />
to the work; this may vary from an inch to the<br />
eighth, or even the sixteenth of an inch, if the work is to be<br />
small. This hollow is then filled with plaster of Paris, well<br />
smoothed, on which the outline of the proposed design is<br />
very accurately traced, and an inked pen is passed over<br />
the outline to preserve it. Very few tools are required by<br />
the workmen, but for the large works, where comparatively<br />
large pieces are to be inserted, small shape-cutting hammers<br />
are made use of for splitting the cakes and reducing<br />
them to their proper size and form ; pincers also, of differ-"<br />
ent forms, are used for placing them equally. In very<br />
small works, instead of hammers, sharp-pointed pincers are<br />
made use of, like those with which diamonds are taken up,<br />
and sometimes a small tool like a scarpello. The heat of<br />
an oil lamp is required, to enable the workman to draw out<br />
the strips of glass to the desired fineness, even to that of
428 A POPULAR TREATISE ON GEMS.<br />
a hair. When this is all ready, the first operation is to dig<br />
or scoop out, with a scarpello of a proper size, a small piece<br />
of plaster of Paris from the bottom of the box or tray,<br />
without injuring the outline ; this is filled up with a kind<br />
of mastic or putty, like that which is used for panes of<br />
glass in the sashes of a window ;<br />
and the required piece of<br />
smalt or glass is then pressed into the composition. In this<br />
way, step by step, and from day to day, repeating the<br />
operation of scooping out a small piece of plaster of Paris,<br />
and never losing sight of the outlines, they gradually fill<br />
up the whole tray. In works of considerable dimensions,<br />
the workmen place the tray before them as painters place<br />
the canvas on which they are painting, and have the original<br />
always close to them. For smaller works they sit at a<br />
table, as if writing, and keep the work flat on the same.<br />
The designs used in these mosaics are for the most part<br />
copied from the pictures of some artist of eminence, the<br />
designers themselves being also a separate body, working<br />
for the mosaicisti, who mechanically fill up the spaces as<br />
above described. When the operation is completed, it is<br />
passed over a stone made perfectly smooth and cleaned of<br />
every kind of dirt ; it happens, however, that interstices,<br />
however minute, will be left more or less between the<br />
several small pieces of smalt inserted into the mastic ;<br />
these<br />
are to be carefully filled up with heated wax, applied with<br />
hot iron instruments from a pallet on which it has been<br />
prepared for the purpose, and much of the good effect and<br />
finish of the work will depend on the ability and care of<br />
the workmen by whom this operation is performed.<br />
A most remarkable specimen of this beautiful art was<br />
shown at the London Exhibition, by the Cavaliere Barbed<br />
; it was a large round table, and represented cele-<br />
brated views in Italy; it was of singular delicacy and<br />
beauty of workmanship, the style of the design, the ex-
MOSAIC AND PIETRA DURA. 429<br />
quisite shading of the colors, the brilliant though softened<br />
effect of the group of views, the atmosphere and sky of each<br />
mingling into the same.ethereal tint, which relieved the eye<br />
and allowed it to rest with pleasure on the separate views :<br />
it was certainly a masterpiece. The author never left- the<br />
Crystal Palace without passing by the table, which always<br />
excited fresh admiration.<br />
There were two other mosaics, much larger than the<br />
former, and different in style, that were remarkably fine<br />
of a celebrated<br />
specimens of workmanship : one was a copy<br />
picture, by Guercino, a St. John the Baptist ; and the<br />
other a portrait of Pope Boniface the Second.<br />
A circular table, a square slab, and a picture representing<br />
a view of PaBstum, were likewise among the Roman<br />
mosaics in the London Exhibition.<br />
Dr. Chilton, of New York, has a beautiful Roman<br />
mosaic of the Pantheon, about three inches long.<br />
In the New York Exhibition, in 1853, the large picture<br />
of Pope Pio IX., in medallion size, was much ad-<br />
mired.<br />
In the Paris Exhibition, in 1855, many large works of<br />
Roman mosaics were exhibited ;<br />
one in particular, belonging<br />
to the Duke of Tuscany, required the constant work<br />
of fourteen years, and cost 700,000 francs. A large table<br />
in the rotunda of the panorama, of rich and elegant Roman<br />
mosaic, cost 400,000 francs. -^<br />
The famous picture of the Campo-vacino, in Home, by<br />
Galand, cost the artist ten years' labor.<br />
Pietra dura, also called Florentine mosaic, consists in<br />
the manufacture of hard stone inlaid in a slab of marble ;<br />
they are, for the most part, of the quartz species, such as<br />
agates, jasper, chalcedony, carnelian, &c. ; also, lapis lazuli,<br />
malachite, and all such hard and colored minerals which,<br />
by their depth of color and brilliancy of lustre largely con-
430 A POPULAB TREATISE ON GEMS.<br />
tribute to produce a picture of a flower or a landscape, and<br />
all come under the name pietra dura of the Florentine<br />
school.<br />
In this kind of work, a slab of marble (generally black),<br />
of the required dimensions, and about one eighth to three<br />
sixteenths of an inch thick, is prepared, and the patterns to<br />
be inlaid are carefully cut out with a saw and file. The<br />
hard stones are worked into the required pattern by the<br />
ordinary methods of gem-cutting, and are accurately fitted<br />
into the spaces thus prepared, in a polished and finished<br />
state ; for if the whole were to be polished at once, some<br />
of the substances being softer than others, would be worn<br />
away too rapidly. The work, also, is liable to be spoiled<br />
by the accidental placing of one stone lower than another,<br />
and mistakes of this kind will often lead to the ruin of the<br />
whole. After the surface is thus prepared it is veneered<br />
on a thicker slab and is then fit for use. In point of diffi-<br />
culty of execution, durability, and taste, this process of<br />
inlaying in hard stones or gems may rank as the most important<br />
purely decorative work within the whole range of<br />
mineral manufactures.<br />
In order to illustrate the peculiar mode of inserting the<br />
different pieces of agate, jasper, &c., in these beautiful<br />
works of art, and to' show also to those not familiar- with<br />
them the elegant and simple forms produced, we give the<br />
following diagram, showing a fac-simile of a portion of<br />
the inlaid-work in one of the tables which were exhibited<br />
in the London World's Exhibition, in 1851.<br />
In this diagram the dark line represents the outline of<br />
the flowers, leaves, &c., and the dotted part, the lines<br />
where the different pieces forming a single object are<br />
joined together. The extreme delicacy and accuracy of<br />
the joints can only be fully appreciated by the examination<br />
of the original specimens.
MOSAIC AND PIETEA DUEA. 431<br />
Fig. 11.<br />
True Florentine mosaic, of fine design and good taste,<br />
was in profusion from Tuscany and St. Petersburg.<br />
A jewel-case belonging to the Empress" of Russia, was<br />
particularly worthy of notice : it was constructed of wood,<br />
having the four sides and top covered with groups of fruit<br />
cut in pietra dura, in a style which may be called cameomosaic<br />
in rather high relief; the stones were so selected as<br />
to afford perfect fac-similes, in color, size, and even in in-<br />
ternal structure, of the fruit they represented, which were<br />
currants, pears, and plums, and the whole work was ex-<br />
quisitely finished.<br />
The King of Sweden sent to the London Exhibition,
432 A POPULAR TREATISE ON GEMS.<br />
an inlaid oblong table of granite, porphyry, and jasper,<br />
of beautiful workmanship ; the materials were the hard<br />
stones of Sweden, which being nearly of equal hardness,<br />
admitted of being polished after the work Was finished.<br />
An Indian chess-table with an inlaid border, and a num-<br />
ber of small objects from India, the ground being a white<br />
marble of a peculiar saccharoidal texture, attracted great<br />
attention. The pattern was a fine scroll-work, remarkable<br />
for the extraordinary delicacy and exactness of the stems<br />
of flowers and the perfect joints<br />
the stems were of flint.<br />
This and another Indian inlaid-work are said to be of great<br />
antiquity. No comparison can be instituted between these<br />
Indian and 'European works, the mechanical execution of<br />
the former being at least equal to the best of those which<br />
have rendered Florence so justly celebrated, while the<br />
taste and design exhibited in them are greatly superior to<br />
inlaid work in marble.<br />
The great expense of inlaying hard- pebbles, which can<br />
only be cut as gems, and the excellent effect that may be<br />
produced by imitations in which marble of various kinds,<br />
shells, cement, and glass, replace the jasper and agate of<br />
Florentine mosaic, have caused the introduction into England,<br />
and elsewhere, of a manufacture which may be called<br />
inlaid marble work. In Derbyshire this branch of manu-<br />
facture has become very important. There are two prin-<br />
that followed<br />
cipal methods of producing marble mosaic ;<br />
in Derbyshire, where a recess is chiselled out of a solid<br />
block of marble, serving as the ground ; and that pursued in<br />
Devonshire, where the whole surface is in fact veneered;<br />
numerous marbles of various colors and forms being merely<br />
cemented together on a base, which may consist of slate,<br />
or any kind of marble; the whole surface being after-<br />
wards polished together. In Malta the former process is<br />
followed, while in Russia the malachite inlaid work is per-
MOSAIC AND PIETRA DURA. 433<br />
formed, as just described. The Duke of Devonshire loaned<br />
his fine collection of Florentine mosaics to the manufac-<br />
turers, from, which they copied the butterflies, leaves, and<br />
sprigs of jessamine, for which these mosaics are so celebrated.<br />
These works being used as guides, the art of inlaying<br />
was brought into successful operation, and materials<br />
foreign to the vicinity, as malachite from Russia, Continental<br />
marbles, Avanturine and other glasses, from Venice,<br />
with some cements, have been introduced into them. The<br />
manufacturers at Matlock, Ashford, Bakewell, Buxton,<br />
Derby, and Castleton are all doing a thriving business.<br />
A table with a wreath of flowers of extremely complicated<br />
pattern, and admirably finished, with a vast number<br />
of detached marbles, of Derbyshire work, owned by Mr.<br />
Yallance, attracted general attention at the "London Exhibition.<br />
Although not to be compared with the Florentine<br />
work, there were, nevertheless, much skill and labor bestowed<br />
upon it.<br />
A number of other tables of inlaid work, of the cinquecento<br />
style, were likewise weh 1<br />
executed. The exhibition<br />
of Derbyshire inlaid work was very large.<br />
A mosaic chess-table from the Isle of Man ;<br />
from Lisbon,<br />
interesting specimens of mosaic, composed of sixty specimens<br />
of Portuguese marbles ; and from the Cape of Good<br />
Hope, a peculiar kind of inlaid marble work, were at the<br />
London Exhibition, and all more or less interesting.<br />
Clay and Porcelain Mosaics*<br />
The encaustic and mosaic tiles used by the ancients for<br />
ornamenting houses, for pavements and walls, have of late<br />
years been extremely well imitated, both in England and<br />
the United States.<br />
The encaustic or inlaid tiles are made by pressing clay in<br />
in
434 A POPULAR TREATISE ON GEMS.<br />
the plastic state into an embossed plaster mould, the pattern<br />
or design on the mould being raised. When the tile is<br />
withdrawn from the mould, the outline of the pattern is<br />
indented, and the indented parts are filled in with colored<br />
liquid clays, according to the colors it is desirable to produce.<br />
The surface is then scraped quite flat, until the pat-<br />
tern appears well defined. The tile is then heated, or as it<br />
is termed, fired, which brings out the colors to the proper<br />
tint.<br />
The Venetian tiles and mosaics are produced by the com<br />
pression of powdered clays into metal dies, of any geometri-<br />
cal form that may be devised, the clays having been previ-<br />
stained with metallic colors. Each tile or tessera is,<br />
ously -<br />
of course, of the same color throughout. When fired,<br />
they are arranged on a smooth platform, with the faces<br />
downward, according to the design intended, after which<br />
liquid Roman or Portland cement is poured upon them,<br />
and they are thus formed into slabs of any size required.<br />
The Alhambra or Spanish tiles are made by pressing<br />
plastic clays into an embossed mould, which forms grooves<br />
or indentations these tiles are then ;<br />
fired, and come out of<br />
the oven with the pattern formed. The indentations are<br />
then filled in with enamels of various colors and fired again,<br />
which produces a brilliant efiect, and renders the tiles suit-<br />
able either for floors or the interior walls of buildings.<br />
A mosaic pavement, composed of tesserce of vitrified clay,<br />
of several colors and shapes, all produced by machinery<br />
with great rapidity, and without the necessity of chipping<br />
any of the tesserce, and at the same time making an endless<br />
variety of patterns, is produced in England, in the follow-<br />
ing manner : The clay being prepared in the usual way,<br />
by washing and sifting, and stained with various metallic<br />
oxides (oxide cobalt, blue smalts, manganese, zaffre, red<br />
lead, crocus mart-is, an rum musivum, oxide chrome, copper
MOSAIC AND PIETEA DTJBA. 435<br />
scales, &c., the principal ingredients used), is formed into<br />
thin ribbons, about three eighths of an inch thick and from<br />
three to four feet long, by a machine ;<br />
out of these ribbons<br />
the tessercB are cut by a patented machine, with great ra-<br />
pidity, and when dry are baked in saggers<br />
in the usual<br />
way.<br />
Pavement slabs are made by laying these tesserae face<br />
downwards on a perfectly flat slate, the pattern, of course,<br />
being reversed, and covering their backs with a layer of<br />
Portland cement, and two layers of rough thin tiles, care-<br />
fully embedded in the cement. In this way strong slabs are<br />
formed, of from an inch and three quarters to two inches<br />
thick, which are almost perfectly impervious to moisture or<br />
rising damp.<br />
The capitol extension, in the City of Washington, United<br />
States, is embellished with encaustic tiles ; and both the<br />
pavement in the halls of the house of representatives and<br />
senate chamber, and the avenues leading to them, and the<br />
encased walls, are laid out with bright-colored tiles, in the<br />
most gorgeous manner.<br />
Mosaic Tiles made with Soluble Glass.<br />
The many useful applications of soluble glass (which<br />
may be the silicate of soda, or the silicate of potash, or<br />
both alkalies combined with the silica), form a new era<br />
in the production of an artificial stone, which, if properly<br />
adapted, must ultimately supersede all other artificial<br />
stones or cements of any kind. If grains of sand, pebbles,<br />
lime, marble, or even granite, clay, and fluor-spar, are<br />
mixed with soluble glass into a paste of the consistency of<br />
putty, and this paste is then moulded into any required<br />
form, after slowly air-drying and burning the articles thus<br />
manufactured in a kiln at a bright-red heat, which may be
436 A POPULAR TREATISE ON GEMS.<br />
maintained for any length of time, by which process the<br />
alkali contained in the soluble glass is set free, the silica<br />
combines with the lime, and more particularly with the<br />
fluor-spar (fluoride of calcium), so durable a cement is<br />
formed thereby, that it will not admit of the smallest<br />
absorption of moisture, and consequently is absolutely unattackable<br />
by frost. By applying the chloride of calcium<br />
in solution to the cement, the supposed objection that the<br />
salts of soda, or alkali, are efflorescing by degrees, is hereby<br />
obviated, for the chloride of calcium at once absorbs the<br />
alkali.<br />
Soluble glass may be colored by various metallic oxides,<br />
so as to produce, when heated, very sharp colors, similar to<br />
enamels, and may also be employed for a coating over<br />
other paints, such as fresco, &c.<br />
As a cement for joining together heterogeneous and ho-<br />
mogeneous substances, it is unsurpassed, and when applied,<br />
renders the substances so coated both water and fire proof.<br />
If soluble glass is intended for a varnish, the proper specific<br />
gravity is 1'165, but for a paint it may be reduced to<br />
that of water.<br />
In France, soluble glass is much used in coating common<br />
building-stones, for the purpose of rendering them<br />
damp-proof. Marble buildings and damp cellars may be<br />
made impervious to dampness by varnishing the surface<br />
with soluble glass ; although the proper mode is to exhaust<br />
the air from the stone or brick, and then impregnate, it<br />
with soluble glass by pressure. A patent was lately taken<br />
out in England, for preserving building, pier, and wharf<br />
stones, by first coating them with a wash of chloride of calcium,<br />
and afterwards by the application of the concentrated<br />
solution of soluble glass, repeating the operation several<br />
times. Soluble glass was introduced into the United<br />
States, by the author of this work, in the year 1831, under
MOSAIC AND PIETEA DURA. 43}<br />
the authority of the government, for the purpose of pro-<br />
tecting the cannon and balls, exposed<br />
to the weather in<br />
the Brooklyn Navy Yard, against rust ; for this purpose,<br />
when treated with the various coloring pigments, such as<br />
oxide of manganese, umber, terra di sienna, ochre, Venetian<br />
red, ultramarine, &c.,<br />
it is admirably adapted.
Q<br />
Chrsobtil<br />
-Jaspe<br />
tus(. Lapis<br />
stoiie Lazuli<br />
mrnam tmwm i<br />
1<br />
'<br />
Diamond<br />
Oriental OK "/: Or.<br />
Topaz, -ItnetfiYst Jlnbv Ckrvsoberfl<br />
-<br />
~~ -<br />
tiarnet Cinnninfini<br />
C 1[H<br />
Chciti-edonv<br />
(Itrxopnise ftridffte Chwsolite Opal<br />
a a<br />
TuriputHSf Malachite Amber<br />
IgM<br />
, 1 HHHI<br />
/>A.-,,y,x, /,dTO ^c Ltpidatitv .Varityan Serpentine<br />
Blood<br />
Hoc/use Labnada<br />
a<br />
Vurblt Porphrrr<br />
Granite<br />
E
EXPLANATION OF PLATES.
PLATE II.<br />
THE MOST REMAKKABLE EOTJGH DIAMONDS.<br />
No. 1. The Nizam, from India; it weighs 340 carats, is valued<br />
at five millions of francs, and belongs to the King of Golconda.<br />
No. 2. The great rough Diamond, as described by Tavernier,<br />
from India, weighing 282 carats.<br />
No. 3. The great South Star, from Brazil, weight when rough<br />
254i carats, was found in the mines of Begagem, in the province<br />
of Minas Geraes, in Brazil. It is as clear as water, slightly tinged<br />
with yellow ; it is valued at two and a half millions of francs ; it<br />
is thirty millimetres in height, forty in length, and twenty-seven<br />
in breadth. Its shape is a twelve-faced rhomboid, presenting<br />
altogether twenty-four triangles.
DIAMOND LATHE.<br />
PL.2.
fTfFjn<br />
-
THE. LARGE ROUGH DIAMONDS.<br />
PL.3
PLATE III.<br />
KEMABXABLE BOUGH DIAMONDS.<br />
No. 4. The great Spheroidal, six-sided, with forty-eight facets.<br />
" 5. The spheroidal Diamond, with twenty-four facets.<br />
" 6. A dodecahedral-pentagonal rough Diamond.<br />
" V. A dodecahedral-rhomboidal rough Diamond.<br />
" 8. An Octahedron, with twenty-four facets.<br />
" 9. An Octahedron, the primary form.
PLATE IY.<br />
REMAKKABLE BOUGH DIAMONDS.<br />
0i 10. A rough Brazilian Diamond.<br />
"<br />
12. A regular Tetrahedron.<br />
" 12. A round, concretional, rough Diamond, called Boort,<br />
"<br />
13. A rough Brazilian Diamond.<br />
" 14. A rough cubical Diamond.<br />
" 15. A rough Brazilian Diamond.<br />
" 16. A truncated octahedron Diamond.<br />
17. A rough Diamond, described by Tavernier.<br />
" is. A triangular crystal of Brazilian Diamond.<br />
" 19. An Octahedron, with modified secondary form.
ROUOH O/AMONOS<br />
PL.4
IUIIFBESI
ROUGH DIAMONDS<br />
PL. 6.
PLATE Y.<br />
No. 1. The improved Diamond Lathe (exhibited in the Paris<br />
Exhibition, 1855, by Phillippe).<br />
No. 2 and 2 a. The pincers, front and side view.<br />
THE PBINCIPLE OF CUTTING.<br />
No. 3. a. The table of a brilliant. &. The triangular faces.<br />
c. The angles terminating into planes, d. Lozenges 4 large and<br />
4 small, e. The planes on the edge of the stone.<br />
No. 3 a.f. The angles parallel with the planes, g. Pavilion<br />
or facets corresponding to Lozenges.* h. The collet of the bril-<br />
liant.<br />
No. 4. A rough Diamond, cleansed.<br />
" 5. Cut of the crown.<br />
" 5 a. The three different cuts. a. The table. 5. The girdle.<br />
c. The collet.<br />
No. 6. A Brilliant not recut.<br />
" 7. A Brilliant recut.<br />
8. Hose Diamond, a. The crown. 5. The facets.<br />
* Lozenge is the geometrical form of a rhomb.
PLATE VI.<br />
THE MOST CELEBRATED OUT DIAMONDS.<br />
No. 1. The Grand Mogul; it weighs 279 carats, and is valued<br />
at twelve millions of francs.<br />
No. 2. The Orlow, the great Russian Diamond, weighs 195<br />
carats, and is the size of a pigeon's egg : cost two millions of francs<br />
and a pension of one hundred thousand francs.*<br />
No. 3. The table Diamond of Ta vernier, weighing 242 carats.<br />
" 4. The Polar Star, weighing 40 carats.<br />
" 5. The Shah, belonging to the Russian crown, weighing<br />
95 carats.<br />
* It is on the top of the Russian sceptre, and has the form of a knob of a cane ; the<br />
under surface is a plane.
THE MOST CELEBRATED CUT DIAMONDS .<br />
PL. 6.
%><br />
tnn<br />
B
6<br />
THE. MOST CELEBRATED CUT DIAMONDS<br />
7<br />
PL.T.
PLATE VII.<br />
THE OELKBEATED OUT DIAMONDS.<br />
No. 6. The Nassack, weighs 78| carats; was sold, in 1839, foi<br />
seven thousand six hundred pounds sterling, to the Marquis ol<br />
Westminster.<br />
No. 7. The great India half-cut Diamond, weighing 112<br />
carats.<br />
No. 8. A brillianted Rose in pear-shape, from India, weighing<br />
16 carats.<br />
No. 9. Another Rose in pear-shape, weighing 94^ carats.<br />
No. 10. A recut India Brilliant, weighing 29 carats.<br />
No. 11 and 11 a. The South Star of Halphen, weighing 124<br />
carats.<br />
No. 12 and 12 a. The Regent, or Pitt ; it weighs 136 carats,<br />
belongs to the French crown, is valued at five millions of francs,<br />
and is certainly the best-proportioned Diamond in the world ; it<br />
is perfectly pure and transparent, and sparkles with a magnificent<br />
play of color.
PLATE Till.<br />
THB CELEBRATED OUT DIAMONDS.<br />
No. 13. The Piggot, belonging to England, weighs 82 carats.<br />
No. 14. The Pacha of Egypt's Diamond, weighs 49 carats.<br />
No. 15. The Koh-i-noor, as it came from India ; and 15 a, its<br />
present form, from a side view.<br />
No. 16. An India pear-shaped Brilliant, weighing 31 1 carats.<br />
No. 17. A Half-Brilliant, faceted, weighing 14J carats.<br />
N"o. 18. Large Rose Diamond, of 280 carats.<br />
No. 19. An irregular Rose Piamond, in pear form, weighing<br />
20 carats.<br />
No. 20, An India Brilliant, described by Tavernier, weighing<br />
52 carats.<br />
No. 21 and 21 a. Large table Diamonds, step-cut.
THE. MOST CELEBRATED CUT DIAMONDS. PL. 8.
;<br />
^
THE. MOST CELEBRATED CUT DIAMONDS .<br />
22<br />
PL. 9.
PLATE IX.<br />
THE OELEBBATED OUT DIAMONDS.<br />
No. 22. The great Austrian Brilliant, belonging to the Grand<br />
Duke of Tuscany, weighing 139 carats ; valued at seven millions<br />
of dollars.<br />
No. 23. The Eugenie Diamond, belonging to the Empress ol<br />
France, weighing 51 carats.<br />
No. 24. The Hope Diamond, a beautiful blue Diamond, weigh-<br />
ing 44i carats.<br />
No. 25. A Brillolet of 16 carats.<br />
No. 26. A knob-shape of 10 carats.<br />
No. 27. A table-shape of 10 carats.<br />
No. 28. A flat Diamond of 20 carats.<br />
No. 29. A flat Diamond of 14 carats.<br />
No. 30 and 30 a. The celebrated Sancy, belonging to the<br />
French crown-jewels, weighing 33 carats, of pear-shape ; is<br />
valued at one million francs.<br />
No. 31. A large cleaved Diamond, of 64 carats, from India.
PLATE X.<br />
Ko. 1. Rock-Crystal Group, from Arkansas, IT. S.<br />
Size and weight of Diamonds, both round and square, from that<br />
of half a carat to 18^ carats.
PL.X.
PL.X/.
PLATE XI.<br />
AMEBICAN<br />
No. 1. California Marble.<br />
u 2. Verde Antique, from Vermont.<br />
3. Shell Marble, from New York.<br />
" 4. Tennessee Marble.<br />
" 5. Bale's Breccia Marble, from Lancaster, Pa.<br />
" 6. Potomac Marble.<br />
" 7. Variegated Marble, from the State of New York.
PLATE XII.<br />
No. 1. Black Marble, with petrified volutes (Pyramidella tur<br />
Unella).<br />
No. 2. Red, green, and white brecciated Marble, from Sicily.<br />
No. 3. Red mottled Marble, tertiary fresh-water Limestone,<br />
from Swabian Alps, cut parallel to the planes of the layers.<br />
No. 4. Pale, yellow, and violet Marble, from the Jura, in<br />
Wiirtemberg.<br />
No. 5. Reddish-yellow and bluish-red mottled Marble, from<br />
Wiirtemberg.<br />
No. 6. Marble, tertiary, cut perpendicularly to the planes oi<br />
the layers, from the Alps.<br />
No. 7. Pale-yellow Marble, and violet Flakes, from Wiirtem<br />
berg.
PL.XI/.
PLJfM.
PLATE XIII.<br />
No. 1. Tertiary brecciated Marble, from the Pyrenees.<br />
No. 2. Red Granite, consisting of red felspar, grey quartz, anc<br />
black mica, from Upper Egypt ;<br />
their monuments.<br />
used by the ancient Egyptians ir<br />
No. 3. Fibrous Calcite, or so-called Thermal Tufa, Sprude 1<br />
stein, from Carlsbad.<br />
No. 4. Compact Brown-spar, from Gibraltar.<br />
No. 6. Agate Marble, from Algiers.
PLATE XIY.<br />
No. 1. Kyanite, light-blue and oblique rhombic prism, with<br />
truncation, from St. Gothard.<br />
No. 2. Amphibole or dark-green Hornblende, Actinolite, an<br />
oblique rhombic prism, from Tyrol.<br />
No. 3. Precious Serpentine, in right rectangular prisms, from<br />
Norway.<br />
No. 4. Lumachelli or Fire Marble, containing fossil shells; the<br />
variegated colors are owing to nautilus or ammonite, from<br />
Corinthia.<br />
No. 5. Ruin Marble, cut perpendicularly to the planes of the<br />
layers, from Tuscany.<br />
-$o, g. Pea-stone, calcareous Stalactite, from the hot springs<br />
of Carlsbad.<br />
No. 7. Dark-brown ribbon Agate, Arabian Onyx,<br />
East Indies.<br />
No. 8. Pale-yellow Marble,<br />
from Florence.<br />
from the<br />
No. 9. Variegated Marble, containing Corals, from the transi-<br />
tion rocks of Nassau.<br />
No. 10. Bed brecciated Marble, from Italy.<br />
No. 11. Black Porphyry, from Sweden.
PLJ(/V.
PL.XV.
No. 1. Egyptian Jasper.<br />
PLATE XY.<br />
No. 2. Ribbon Jasper, striated with red and green, froir<br />
Siberia.<br />
No. 3. Pudding-stone or Quartz Conglomerate, from Scotland.<br />
No. 4. Horny-colored Agate, from the East Indies.<br />
from the East Indies.<br />
No. 5. Chrysolite,<br />
No. 6. Noble Garnet, Pyrope, from Bohemia.<br />
No. 7. Dark-yellow Topaz, burnt, and called Balais, from<br />
Brazil.<br />
No. 8. Granite,<br />
from Milan.<br />
No. 9. Wood Opal, a petrified pine, from Hungary.<br />
No. 10. Black ribbon Agate, from the East Indies.<br />
No. 11. Green Tourmaline (Brazilian Emerald) in Dolomite,<br />
from St. Gothard.<br />
No. 12. Moss Agate or Mocca-stone, from the East Indies.<br />
No. 13. Dark Topaz, from Brazil.
PLATE XVI.<br />
No. 1. Black and white mottled Marble, from the monotniE<br />
limestone of Ardennes.<br />
No. 2. Red antique Porphyry, from Upper Egypt.<br />
No. 3. Blue Copper, Azurite, from Germany.<br />
No. 4. Malachite, Green Copper, from Siberia.<br />
No. 5. Natrolite on Clinkstone, from Bavaria.<br />
No. 6. Clear-yellow Amber, inclosing several flies, from the<br />
coast of the Baltic, near Dantzic.
PL.W.
PLXVII.
PLATE XVII.<br />
No. 1. Dark-green Serpentine, from the Apennines.<br />
No. 2. Amazon-stone or apple-green Felspar, an obliqne rhom<br />
bic prism, from the Ural Mountains.<br />
No. 3. Fortification Agate, from Oberstein.<br />
No. 4. Green Porphyry Felspar, from Greece.<br />
No. 5. Serpentine, Ophicalite, or Verde de Corsica duro, from<br />
Corsica.<br />
No. 6. Labrador Felspar, from Labrador.
458 INDEX.<br />
Borax, double refraction of, 88; reagent,<br />
116.<br />
Botryoidal, 72.<br />
Brachydiagonal, 46.<br />
Brachydomes, 47.<br />
Brachypyramids, 47.<br />
Brazil, discovery of diamonds in, 1ST;<br />
revenue from diamonds in, 201.<br />
Brewsterline, 265.<br />
Brilliant, the, 161.<br />
Brillionets, 161.<br />
Bromine, 119.<br />
Bronzite, fusibility of, 116.<br />
Brown spar, 56.<br />
Burning of gems, 171.<br />
Cabochon cut, 165.<br />
0.<br />
Cachelong, an opal, 807.<br />
Cadmium, test of; 125.<br />
Cairngourm crystals, 261.<br />
Calamine, 55.<br />
Calc spar, 43, 65, 66, 70, 73 ; hardness, 78 ;<br />
double refraction, 86; varieties of, 364.<br />
Calcareous scheelite, refraction of, 88.<br />
Cameos, shell, 425.<br />
Cannel coal, described, 354.<br />
Carat, origin of the word, 181 ; weight of<br />
four grains, ib.<br />
Carbon, 120.<br />
Carbonate of soda, reagent, 116; refraction<br />
of carbonates, 87; electricity, 99.<br />
Carbuncle (see Spinelle), 228 ; garnet, 251.<br />
Carengeair's goniometer, 5S.<br />
Cornelian, hardness of, 80; described, 279.<br />
CatVeye quartz, described, 270.<br />
Caves, list of American, 880.<br />
Cerium, test of, 127.<br />
Chabasite, 56, 65.<br />
Chalcedony, 73; hardness of, SO; refraction<br />
of, 88 ; described, 277. Varieties 1,<br />
Chalcedonyx; 2, Mochastones; 3, Kainbow<br />
: 4, Cloudy ; 5, Plasma ; 6, Semicarnelian<br />
or ceregat ; 7, Sappharine ; 8, St<br />
Stephen's stones, 278; varieties of, 77.<br />
Chalcopyrite, 64.<br />
Chalk, 365.<br />
Chemical properties of minerals, 102 ; reac-<br />
tion, 113.<br />
Chlorine, 119.<br />
Chlorophane (a fluor spar), 335.<br />
Chromate of lead, refraction of, 87.<br />
Chromium, test of, 127.<br />
Chrysoberyl, degree of hardness, 80 ; real<br />
gem, 136; same as cyinophane, 225.<br />
Chrysolite (Peridote, olivin), nardness ot,<br />
80 real ; gem, 136 ; oriental, a sapphire,<br />
216; refraction of, 87; Ceylon, a tourmaline,<br />
256; described, 294.<br />
Chrysoprase, described, 292 ; value, 294.<br />
Cinnabar, refraction of, 88.<br />
innamon stone or Essonite, 253 ; see Hya-<br />
cinth de Ceylon.<br />
Cleaning gems, 172.<br />
Cleavage, varieties of; 76.<br />
Clinopinacoids, 51.<br />
Clinoprisms, 51.<br />
Clinopyramids, 51.<br />
American coal-fields, ib.<br />
Coal, 354 ;<br />
Cobalt, solution of, reagent, 117; test of,<br />
125.<br />
Cobaltine, 80, 31.<br />
Collet the, explained, 161.<br />
Colophonite, a garnet, 249.<br />
Color, change of, 93; table of colors of<br />
minerals, 96 of ; gems, 136.<br />
Combinations, 81.<br />
Conazeranite (felspar), 314.<br />
Copper, test of, 126.<br />
Coral, described, 419 ;<br />
varieties of red, 422.<br />
Cordierite, a real gem, 136.<br />
Corundum, hardness, 78 refraction ;<br />
of, 87 ;<br />
description of, 214; see Sapphire.<br />
Corundum, common, or Diamond spar, de-<br />
scribed, 223 ; granular, or emery, 224.<br />
Crown-jewels of France, value of; 207.<br />
Crown-jewels of Queen Victoria, 210.<br />
Cryptoiine, 265.<br />
Cryptocrystalline minerals, 73.<br />
Crystalline, 19.<br />
Crystallized, 19.<br />
Crystals, defined, 20 ; described, &. ; systems<br />
of, ib. ; imperfections of, 54 ; strise<br />
55 ; drusy, 56 ; measurement, 58 ; macles<br />
or tw4n crystals, 61 ; irregular aggrega-<br />
tion, 70.<br />
described, 827.<br />
Cyanite, 73 ;<br />
Cymophane (oriental chrysolites), refraction<br />
of, 87 see ; Chrysoberyl.<br />
D.<br />
Deltoid dodecahedrons, 28; sign, 80.<br />
Derivation of forms, 27.<br />
Diamond, 24, 25, 29; hardness of, 78, 80 i<br />
double refraction of, 87 ; first cut by Ca-<br />
radossa, 151 ; manner of cutting, 156, 183 ;<br />
polishing, 158 ; forms of, 161 ; discovery<br />
in a diamond lens, 182 ; general account<br />
of, 183, etc. ; pure carbon, 184; artificial,<br />
ib. ; form of crystals, 185 ; color, ib. ; the
compact, ib. ; the original bed of, 187:<br />
loss In cutting, 193; Hindoo division of.<br />
195; value, Vt. ; color, purity, ib.; de-<br />
gree of clearness, ib. ; cat and size, 196;<br />
prices of, 197-8; celebrated diamonds,<br />
154, 193, 203 ; the largest known, 208 ; in<br />
Victoria's crown, 211 ;<br />
Exhibition, 212.<br />
Diamond grinders, 155.<br />
at the Industrial<br />
Ditetragonal, pyramids, 36.<br />
Divelsteene, 156.<br />
Dodecahedrons, subdivided, 22.<br />
Dolomite, double refraction of, 87.<br />
Double facet cut, 165.<br />
Doublets, 180.<br />
Druses, 71.<br />
Drusy crystals, 56.<br />
Dyakisdodecahedron, 30; sign, 31.<br />
E.<br />
Edingtonate, double refraction of, SS.<br />
Electricity of minerals, 99.<br />
Electro-chemical elements, table of, 105.<br />
Electroscopes, 99.<br />
Elongated brilliant facet cut, 165.<br />
Emerald, hardness of, 80; double refrac-<br />
tion, 85; a real gem, 136; the oriental, a<br />
sapphire, 216; described, 235; emerald<br />
proper, ib.; how cut, 237; value, ib.;<br />
remarkable emeralds, 238 ; the Duke of<br />
Devonshire's, 239 ; the Brazilian, a tour-<br />
maline, 256.<br />
Emery, a common corundum, 224.<br />
Engraving on gems, 167.<br />
Essonite, or cinnamon-stone ; hardness of,<br />
80; real gem, 136, 250; described, 253.<br />
Euclase, double refraction of, 87; description<br />
of, 234.<br />
Facets, 161.<br />
.Fablore, 63.<br />
F.<br />
Felspar, 52, 53, 75; described, 312; common,<br />
315; ad ul aria. 312; march isonite.<br />
814; leclite or helleniaU, conazeranite.<br />
ib.; amazon-stone, 315; porphyry, 391 ;<br />
sienete, 893.<br />
Fish-eye (adularia), 31i<br />
INDEX. 459<br />
Fluor spar, crystalline forms, 23 24, 25, 56,<br />
63, 65, '70; hardness, 78, 80; ciouble re-<br />
fraction of, 88; electricity, 99; describ-<br />
ed, 333.<br />
Fluorine, test for, 120.<br />
Foil, use of, 169.<br />
Form, primary, 26 ; semi-tesseral, 28 ; parallel<br />
semi-tesseral, 30.<br />
Forms of crystalline aggregates, 71.<br />
Dimorphism, 110.<br />
Fortification agate, 284.<br />
Dioptase, double refraction of, 88.<br />
Fracture surfaces, 78.<br />
Disthene<br />
321.<br />
(Kyanite, sappare), described, Fusibility, test minerals as to, 115.<br />
Galena, 23, 24, 56, 63.<br />
G.<br />
Garlic, used in repairing gems, 170.<br />
Garnet, 23, 25, 27 ; hardness of, 80 ; double<br />
refraction of, 88 ; magnetic, 100 ; a real<br />
gem, 136 ; described, 247 ; varieties, 24S ;<br />
Syrian, Bohemian, Ceylonian, Aplome,<br />
ib.; precious or almandine, 24S ; coloph-<br />
onite, 249; allochroite, ib.; grossular,<br />
250; topazolite, ib.; melanite, pyrenaite,<br />
ouwarowite, ib.; the ancient car-<br />
buncle, 251.<br />
Gems, 135; enumerated, 136; color, gravity,<br />
and hardness of, ib.; chemical char-<br />
acter, 139; composition, ib.; artificial<br />
production, 140 ; geological character,<br />
145; geographical distribution, 140; division<br />
and nomenclature, 147; history<br />
of, 148; superstitions as to, 149; sculpture<br />
in, 151 ; grinding, 153 ; engraving,<br />
167; sawing and drilling, 168 ; polishing<br />
materials, ib.; heightening color of, 169 ;<br />
setting, 171; cleaning of, 172; imitations,^.;<br />
1, pastes, ib.; 2, doublets, ISO ;<br />
3, burning, 180; price of, 181; optical<br />
use of, 181.<br />
Girasol sapphire, 216 ; fire opal, 304 ; adu-<br />
laria, 313.<br />
Girdle, in diamonds, what? 161.<br />
Glucina, test of, 123.<br />
Goldstone, a paste, 278.<br />
Goniometers, 58.<br />
Goutte de sang, a spinelle, 228.<br />
Grand mogul diamond, 193, 203.<br />
Granite, described, 896; American varie-<br />
ties, 397.<br />
Gray copper ore, 28, 68.<br />
Grossular garnet, 250.<br />
Gypsum crystals, 51, 56, 68, 74; doable<br />
refraction of, 88 ; tntin gypsum, 341 ; al-<br />
abaster, ib.
460<br />
H.<br />
INDEX<br />
Haematite, 65.<br />
Hardness of minerals, 78 ; Mob's, scale of,<br />
ib.; rough scale, 79 ; of precious stones,<br />
80 ; of gems, 136.<br />
Hatchet-stone (jade), 361.<br />
Hausmanite, 64.<br />
Hauyne, described, 822.<br />
Heliotrope, described, 282.<br />
Hellefliata, or Leclite (felspar), 314.<br />
Helvine, 28.<br />
Hemihedric crystal, 21.<br />
Hetnimorphism, 54.<br />
Hemiorthotype system, 21.<br />
Hexagonal system, 21, 39; pyramids 40;<br />
dihexagonal, 41 ; rbombohedral, 42.<br />
Hexahedron, 22, 23 ; sign of, 27.<br />
Hexakisoctahedrons, 25 ; sign of, 27.<br />
Hexakistetrahedron, 28; sign, 30.<br />
Holland diamond, 206.<br />
Holobedric crystals, 21, 22.<br />
Hope diamond. 206.<br />
Hornblende, 68, 320.<br />
Hornstone, described, 277.<br />
ous property, ib.<br />
Hydroxide of iron, double refraction of, 88.<br />
Hypersthene, not hornblende, 820; de-<br />
scribed, ib.<br />
I.<br />
Iceland spar, 66 double ;<br />
refraction of, 86 ;<br />
described,. 364<br />
Icositetrahedrons, 22, 24 ; sign of, 27.<br />
Idocraso, double refraction of, 88 ;<br />
ed, 321.<br />
Ignoble metals, 101.<br />
Imitations of gems, 172.<br />
Indicolite (Brazilian sapphire), 256.<br />
Iodine, test for, 119.<br />
describ-<br />
lolite, real gem, 136; described, 297; di-<br />
chroite; peliom, lynx and water sapphire,<br />
298.<br />
Iridescence, 93.<br />
Iron, double refraction of, 88; test olj<br />
127.<br />
Iron pyrites, 30, 81, 55, 68.<br />
Irregular aggregation, 70.<br />
Isomorphic substances, 111.<br />
Isomorphism, 110.<br />
Itacolumite, diamond-bearing rock, 188.<br />
J.<br />
Jade (nephrite, hatchet-stone, punamu),<br />
described, 361.<br />
Jargon (see Zircon), 244 ; described, 246.<br />
Jaspachates, a variety of agate, 284<br />
Jasper described, 273 ; varieties : 1, Egyptian<br />
; 2, Ribbon spar, 276 ; jasper opal,<br />
308.<br />
Jet, hardness of, 80 ; described, 353 ; a bituminous<br />
coal, ib.<br />
Jewish tribes, gems allotted to, 149.<br />
Jeweller's wax, 172.<br />
Hyacinth, hardness of, 80; oriental, a sapphire,<br />
215; a variety of zircon, 246 ; described,<br />
247.<br />
Hyacinth de Ceylon (Essonite, or cinnainon-stone),<br />
258.<br />
Hyaline, 19.<br />
Hydrate of magnesia, double refraction<br />
of, 88.<br />
Hydrometer, 81.<br />
Hydrophane, a variety of opal, 305 ; curi-<br />
Kaolin, 75.<br />
Kneeshaped crystal, 64.<br />
Kohinoor, a celebrated diamond, 154; its<br />
loss in cutting, 193 ; history of, 208.<br />
Kuinur, a celebrated diamond, 154.<br />
Kyanite (sappare, disthene) described, 827.<br />
L.<br />
Labradorite, 70 ; not felspar, 317.<br />
Lamellar, 71.<br />
K.<br />
Lapidaries, ancient, 151; s6ciety of, 153;<br />
gem lapidary, 163; common, 164; his<br />
apparatus, ib.<br />
Lapis lazuli, or Armenian stone, described,<br />
322 ; uses of, 323.<br />
Lava described, 360.<br />
Lava, black glass lava, or obsidian, 310.<br />
Lazulite, hardness of, 80 ; azure-stone, 324 ;<br />
used to imitate lapis lazuli, ib.<br />
, 66 ; test of, 125.<br />
Leclite (felspar), 314.<br />
Lepidolite, described, 339.<br />
Leucite, 27.<br />
Lievrite, 48.<br />
Lithia, test of, 121.<br />
Lime, test of, 122.<br />
Lithographic stone, 366.<br />
Love's arrows, a rock crystal, 261.<br />
Lustre, 93 ; degrees of, 94 ; varieties of, ib<br />
Lyncurium, not tourmaline, 258.
M.<br />
Macles or twin crystals, 61.<br />
Macrodiagonal, 46.<br />
Macrodoines, 48.<br />
Macropinacoid, 48.<br />
Macroprisms, 48.<br />
Magnetic iron ore, 24, 63.<br />
Malachite, 74; hardness of, 80; describ-<br />
ed, 835; beautiful articles made of,<br />
338.<br />
Manganese, test of, 125.<br />
Marble (Carbonate of lime), described, 264;<br />
best localities, 366 ; ancient marbles, 367 :<br />
French, ib. ; English, 863; varieties of<br />
Derbyshire, ib. ; marble statuary, 370,<br />
876 ; American marbles, 871, 8S3 ; white,<br />
ib. ; ancrinital or bird's-eye, 372 ; mar-<br />
bles, &c., in N. Y. Geological cabinet,<br />
373 ; breccia, 375 ; serpentine or verd an-<br />
tique, ib. ; leocadia breccia, 876 ; Egyptian,<br />
382; Italian, ib. ; shell marble,<br />
885.<br />
Marcasite, 66 ;<br />
or pyrites, 390.<br />
Marekanite, brown obsidian, 310.<br />
Measurement of crystals, 58.<br />
Meerschaum, described, 857; uses of,<br />
358.<br />
Meionite, double refraction of, 888.<br />
Melanite, garnet, 250.<br />
Mellite, double refraction of, 88.<br />
Mercury, test of, 124<br />
Mica, double refraction of, 88 ; described,<br />
'<br />
889.<br />
Microcosmic salt, reagent, 116.<br />
Mineralogy, how limited in this work,<br />
16.<br />
Minerals, forms of, 19 ; crystalline, amorphous,<br />
ib. ; physical properties, 75 ; hardness<br />
and tenacity, 73 ; specific gravity of,<br />
SO; optical properties, 84; double re-<br />
fraction, 85; polarization of light, 89;<br />
pleochroism, 92 ; iridescence, 93 ; lustre,<br />
ib.; color, 95; phosphorescence, 98;<br />
magnetism, 100 ; smell, taste, touch, 101 ;<br />
chemical properties, 102; composition,<br />
ib. ; influence of chemical composition<br />
on external character, 109; chemical re-<br />
action, 113; fusibility, 114-; solubility,<br />
orders of, 134<br />
11T; classification, 129 ;<br />
Mispickel, 66.<br />
Mix facet cut, 164<br />
Mocha stones, chalcedony, 278.<br />
Mobs; his system of crystallization, 21;<br />
scale of hardness, 73.<br />
Molybdite, double refraction of, 88.<br />
IND EX. 461<br />
Monoclinochedric system, 21, 49 ; its forae,<br />
49; combinations, 51.<br />
Months, gems, allotted to, 149.<br />
Moonstone (Adularia), 318. *<br />
Moroxite, an oolite, 387.<br />
Mosaic, 426; Roman, 427; Florentine or<br />
pietra dura, 429; clay and porcelain,<br />
433.<br />
Murchisonite (felspar), 314'<br />
Nassak diamond, 198; its value, 200, 204,<br />
210.<br />
Natrolite, fusibility of, 115; described, 332.<br />
Naumann, his system of crystallization, 21.<br />
Nepheline, double refraction of, 88.<br />
Nephrite or jade, 361.<br />
Nicholson's hydrometer, 81.<br />
Nickel, magnetism of, 100; test of, 125.<br />
Nitric acid, test, 119.<br />
Nizam diamond, 208.<br />
Noble metals, 108.<br />
Non-metallic elements, 113.<br />
o.<br />
Obsidian, hardness of, 80; described, 809.<br />
Octahedron, 23; primary form, 26; how<br />
distinguished, ib.<br />
Ofigoclase, 69.<br />
Olivin, or Chrysolite, 294<br />
Ouwarowite, garnet, 250.<br />
Onyx, carnelian, 280 ; agate, 288 ; describ-<br />
ed, ib. ; cameos of, ib.<br />
Oolite, a calcareous spar, 365, 836.<br />
Oolitic crystals, 78.<br />
Opal, 73 ; hardness, 80 ; double refraction,<br />
88 ; iridescence, 93 ; described, 299 ; precious<br />
opal, ib. ; mother of opal, 801 ; celebrated<br />
specimens, 802; fire opal, or<br />
girasol, 304 ; common opal, 805 ; hydro-<br />
phanes, ib. ; semi-opal, 806 ; wood opal,<br />
ib. ; cachelong, 807 ; Jasper opal, 808 ;<br />
Ceylon or water opal, ib.<br />
Orders of minerals, 137.<br />
Oriental and occidental gems, 147. .'
462 I N DEX.<br />
P.<br />
Pastes and artificial gems, 172 ; receipts fo<br />
colored, 176 how ; detected, 179.<br />
Paunched diamonds, 195.<br />
Pavilion facets, 162, 164<br />
Pearls described, 400; how formed, ib.<br />
localities, 401; value of, 407; Unite<br />
States pearls, 409 ; artificial, 415.<br />
Peliom, a variety of iolite, 298.<br />
Pentagonal dodecahedron, 30; sign, ib.<br />
Pentagonal dodecahedron, and pentagona<br />
icositetrahedron, not observed in nature<br />
. 81.<br />
Peridote (see Sapphire, Chrysolite),216, 294<br />
Phosphates of lead and lime, double re<br />
fraction of, 88.<br />
Phosphate of lime, 388 ; its uses, ib.<br />
Phosphorescence, 98.<br />
Phosphoric acid, test of, 118.<br />
Phosphorite, 388.<br />
Pietra dura (Florentine mosaic), 429.<br />
Piggot diamond, 206.<br />
Pisolite (calcareous spar), 365, 386.<br />
Plasma, chalcedony, 278.<br />
Plaster of Paris ; a gypsum, 342; constitu-<br />
ents, ib.<br />
Platinum, test of, 126.<br />
Pleochroism, 92.<br />
Point diamonds, 161.<br />
Polar-star diamond, 206.<br />
Polarization of light, 89; instrument for<br />
observing, 90.<br />
Porodine, 19.<br />
Porphyry, a compact felspar, 391 ;<br />
can varieties, 392.<br />
Potassa, test of, 121.<br />
Prase, common quartz, described, 271.<br />
Prehnite, 56.<br />
Prismatic topaz, hardness, 78.<br />
Pseudomorphism, 74.<br />
Punamu (jade), 361.<br />
Ameri-<br />
Pyramidal system, 21.<br />
Pyrenaite, garnet, 250.<br />
Pyrites described, 390; also called Marca-<br />
site, ib.<br />
Pyrope, a garnet, 248.<br />
Q.<br />
Quartz cpmmon, Eose quartz, cats-eye,<br />
prase, avantnrine, 269.<br />
Quartz crystals, 55, 56; hardness, 78 ; double<br />
refraction of, 87, 88 ; an oxidized stone,<br />
184; a gem^ 136 ; described, 259.<br />
Queen Victoria's crown, 210.<br />
R.<br />
Rainbow chalcedony, 278.<br />
Bed silver, double refraction, 88.<br />
Eefraction, double, 85 ;<br />
table of, 87.<br />
Eegent diamond, 154, 193, 204.<br />
Eeniform crystals, 72.<br />
Ehombic system, 21, 45.<br />
Ehombic dodecahedron, 23 ; sign of, 27.<br />
Ebombohedral system, 21.<br />
Ehombohedron, 42 ; combinations, 44.<br />
Eibbon spar, 276.<br />
Eock of Gibraltar, carbonate of lime, 386<br />
Eock crystal, 78; hardness of, 80; de-<br />
scribed, 260; varieties, 261; specimens,<br />
262; water in them, 265.<br />
Eock salt, hardness, 78; double refrac-<br />
tion, 88.<br />
Rose diamond, 162.<br />
Rose manganese, described, 391.<br />
Rose quartz, 269.<br />
Eubellite, double refraction, 88; a real<br />
gem, 136 ; tourmaline, 255.<br />
Euby, hardness of, 80 ; a variety of sapphire,<br />
214, 215.<br />
Juby cat's-eye, 216.<br />
Euby spinelle, almandine, balais, varieties<br />
of spinelle, 227, 228.<br />
lussia, discovery of diamonds in, 189.<br />
~^util, double refraction of, 88.<br />
Saline ores, 134.<br />
aline stones, 134.<br />
s.<br />
ancy diamond, 204 ; history of, ib.<br />
iappare (kyanite, disthene), described, 327.<br />
appharine, a chalcedony, 278.<br />
sapphire, hardness of, 80 ; iridescence of,<br />
93 ; real gem, 136 ; synonymous with<br />
corundum, 214 ; description of, ib.; va-<br />
rieties, 215; ruby, oriental hyacinth,<br />
amethyst, sapphire, and topaz, 215;<br />
aquamarine, chrysolite, and emerald,<br />
216; its constituents, 216; locality, 217;<br />
mode of cutting, ib.; uses, 219 ; value,<br />
ib. ; remarkable sapphires, 221, 222 ;<br />
Brazilian sapphire or indicolite, a tour-<br />
maline, 256 ; lynx and water sapphire,<br />
iolites, 298.<br />
arda, ancient name for Carnelian, 279.<br />
ardonyx, a carnelian, 280; agate, 289'<br />
cameos and intaglios, 290.<br />
atin gypsum, described, 341.<br />
atin spar, described, 340.<br />
calenohedron, 43.
Scapolite, 79.<br />
Schlaggenwald fluor spar, 70.<br />
Schorl, electric, a tourmaline, 256; origin<br />
of the name, 258.<br />
Sculptors in gems, 152.<br />
Selenium, test for, 118.<br />
a chalcedony, 1b.<br />
Semi-camel ian, 278 ;<br />
Semi-tesseral forms, 28.<br />
Serpentine, described, 362.<br />
Setting of gems, 171.<br />
Shah diamond, 206.<br />
Shrugging in diamonds, 195.<br />
Siberite, a tourmaline, 255.<br />
Siderite, 56.<br />
Sienite (felspar and hornblende), 893;<br />
American varieties, 894.<br />
Signs, crystallographic, 27.<br />
Silver, test of, 126.<br />
Soda, test of, 121.<br />
Solubility, .17<br />
Soluble glass, 435.<br />
Somerviilite, double retraction of, 88.<br />
South star diamond, 193, 210.<br />
Specific gravity of minerals, 80 ; how as-<br />
certained, ib,; of gems, 136.<br />
Spinel, spinelle, 23, 63; hardness, 80;<br />
double refraction, 87; real gem, 136;<br />
described, 227; constituents, ib.; varie<br />
ties, 227, 223; ruby spinelle, ruby balais,<br />
almandine ruby, goutte de sang, ib.; im-<br />
itation, 229.<br />
Stalactite, 73, '365; described, 380.<br />
Stalagmite, 73 ; described, 380.<br />
Star facets, 162.<br />
Star of the south, 210.<br />
Staurolite, 66.<br />
Stephanite, 66.<br />
Stilbite, 48, 56.<br />
Strahlstein, fusibility of, 115.<br />
Striae, 55.<br />
Strontia, test of, 122.<br />
St Stephen's stone (chalcedony), 278.<br />
Stygmite, a carnelian, 281.<br />
Sulphate of baryta, 87.<br />
T.<br />
Table of a diamond, 161.<br />
Table diamond, 163.<br />
Talc, hardness of, IS.<br />
Tantalium, test ot, 128.<br />
INDEX. 463<br />
Tchingtching (lapis lazuli). 325.<br />
Tellurium, test ot, 124.<br />
Tenacity of minerals, 80.<br />
Terminology, 19.<br />
Tesseral, or tessular system, 21 ; described,<br />
82.<br />
Tetragonal system, 21, 34; closed forms,<br />
35 ; tetragonal pyramids, ib.; ditetragonal,<br />
ib.; tetragonal sphenoids, 36; tet-<br />
ragonal scalenohedrons, ib.; open forms,<br />
86 ; tetragonal prisms, ib.<br />
Tetragonal crystals, how distinguished, 87.<br />
Tetrahedral form, 28 ; its sign, 29.<br />
Tetrakishexahedrons, 24 ; sign ot, 27.<br />
Thorina, test of, 123.<br />
Thumerstone, or axinite, 31L<br />
Tin, test of, 125 tin ; ore, 64.<br />
Titanium, test of, 129.<br />
Topaz, crystal, 48; hardness, 80; optical<br />
power, 87; electric, 99; a real gem,<br />
136; description of, 229; varieties, 230 ;<br />
cutting of, 231; localities, 232; imita-<br />
tions, 233; engraved topazes, ib.; topaz<br />
of the ancients, 229, 234.<br />
Topazolite, 250.<br />
Tourmaline, 55, 56; double refraction oft<br />
88; polarization of light, 89; real gem,<br />
136; described,- 254; composition of,<br />
255; 1. Siberian (siberite, rubellite, apyrite),<br />
ib.; 2. Indicolite (Brazilian sapphire);<br />
S.Brazilian (emerald); 4. Ceylon<br />
(chrysolite) ; 5. Electric schorl, 256 ; lo-<br />
calities, ib.; fine, specimens, ib.; not lyncurium<br />
of the ancients, 258.<br />
Triakisoctahedron, sign o^ 27.<br />
Triclinohedrie system, 21, 52; pyramids,<br />
53 ; combinations, ib.<br />
Trigonal dodecahedrons, 28 ; sign, 29.<br />
Tufa, calcareous spar, 365.<br />
Tungsten, test of, 128; see Wolfram.<br />
Turquoise, hardness of, 80 ; described, 329 ;<br />
1. true oriental; 2. bone, or occiden-<br />
tal, 330.<br />
Sulphur, 48; refraction of, fc7 ; test for, 118.<br />
u.<br />
Sunstone, sapphire, 216; iridescence of,<br />
93; adnlaria, 313.<br />
Ultramarine, made from lapis lazuli, 324;<br />
Systems of crystals, 21.<br />
how prepared, 325; imitations, 826.<br />
Uranium, test ot; 128.<br />
Y.<br />
Vanadium, test of, 128.<br />
Variolite (felspar), 814.<br />
Venus' hair, 261.<br />
Volcanic glass, or obsidian, 80fc
4G4<br />
W.<br />
INDEX.<br />
Water in rock crystal, analysis of, 265.<br />
Weiss and Rose, system of crystalliza-<br />
Yttria, test of, 128.<br />
tion, 21.<br />
Wernerite, double refraction o 88.<br />
Wolfram, 68; test of, 120; see Tungsten.<br />
Wollaston's goniometer, 58.<br />
z.<br />
Zircon,<br />
123; described, 244; same as hyacinth<br />
uroodstone, 2TT.<br />
ib.; varieties, 245.<br />
Zuisang (lapis lasuli), 825.<br />
Zinc, blend, 64 test of 124.<br />
;<br />
double refraction of, 87; test of
APPENDIX.<br />
CHRONOLOGICAL LIST<br />
OF<br />
WORKS ON GEMS AND MINERALS<br />
SINCE THE FIFTEENTH CENTUBY.<br />
BECHAI, (Ben Ascliar,) Biur al Hattorah, (Exposition of the Law of<br />
Moses,) a Commentary on Exodus xxviii. 17-20* A. M. 5207,<br />
(A. D. 1447.*)<br />
Plinii secundi, (Caii,) Naturalis Historia. Fol. Venice, 1469.<br />
Aristotle, Lapidarius, de novo e Graeco translatus. Lucas Brandis.<br />
4to. Eegia Mer&ourg, 1473.<br />
Serapion, (John,) De Medicamentis tarn simplicibus quam compositis.<br />
Mediolanum, 1473.<br />
Alberti, (Magni,) Philosophorum maximi de Mineralibus. Libri V.<br />
Patavii, 1476.<br />
Avicenna, (Abou-Ali-Alhussein-Ben-Adloulah,) Canones Medicinae,<br />
Latt. reddit. Venice, 1483.<br />
Csesalpinus, (Andreas,) De Metallicjs Libri tres. 4to. Rom. 1496.<br />
Leonardus, (Camillus, M. D.,) Speculum Lapidum. 4to. Venet.<br />
1502.<br />
* This work contains an ample account of the properties of precious stones.<br />
The edition of 1447 is the earliest, but it has since been many times re-<br />
printed.
466 APPENDIX.<br />
Aben Ezra, (Rabbi,) Commentarium in Decalogum. 8vp. Hehr.<br />
Basel, 1527.<br />
Rue, (Franc, de la,) De Gemmis. 8vo. Parisii, 1547 ; 8vo. Lugd.<br />
1622 ; 12mo. Franc. 1626 ; 12mo. Gron. 1626.<br />
Agricola, (G.,) De Re Metallica, Libri XI. ; et de Natura fossijium,<br />
Libri X. Fol. BasUice, 1546.<br />
Ruens, (F.,) De Gemmis aliquot, iis prsesertim quarum Divus Joannes<br />
Apostolus in sua Apocalypsi notavit. 8vo. Paris, 1547.<br />
Libravii (Andr.,) Singularium libr. IV. quorum I. et III. de metallis<br />
lapidibus, et fossilibus. 8vo. Franco/. 1549 ; also in 1601.<br />
Encelius, (Christoph,) De Re Metallica, hoc est, de origine, varietate<br />
et natura corporum metallicorum, Lapidum, Geinmarum atque<br />
aliarum quae ex fodinis eruuntur Libri III. 8vo. Francf. 1551.<br />
Theophrasti, (Eresii,) Opera omnia, Greece, cura Camotii edidit F.<br />
Turisanus. 70. Venetus, apud Aldi filios, 1552.<br />
Langius, (Johannes,) Epistolse Medicinales. Fol. Lugd. 1557.<br />
Agricola, (George,) De Ortu et Causis Subterraneorum. De Natura<br />
eorum quse effluunt ex Terra. Fol. Bas. 1558.<br />
Mandeville, (John,) Le Grand Lapidaire, ou sont declarez les noms<br />
de Pierres orientales, avec les Vertus et Proprietes d'icelles, et iles<br />
et pays ou elles croissent. 12mo. Paris, 1561.<br />
Porta, (Giov. Baptista,) Magiae Naturalis Libri IV. Antwerp, 1561.<br />
Fallopius, (G.,) De Medicatis Aquis atque de Fossilibus, tractatus ab<br />
Andrea Marcolino collectus. 4to. Venitia, *1564.<br />
Dolce, (Ludovico,) Libri tre, nei quali si tratta delle diverse sorti<br />
delle Gemme che produce la Natura. 8vo. Yen. 1564.<br />
Rulandus, (Martinus,) Medicina Practica, 12mo. Arg. 1564.<br />
Gesneri, (C.,) De omni rerum fossilium genere, gemmis lapidibus,<br />
metallis, &c. 8vo. Tiguri, 1565.<br />
Leonardus, (Camillus;) Trattato delle Gemme che produce la Natu-<br />
ra ; traduzione di M. Ludovico Dobe. 8vo. 1565.<br />
Gesner, (Conrad,) Liber de Rerum fossilium, Lapidum, et Gemmarum,<br />
maxime figuris, etc. 8vo. Tig. 1565.<br />
Epiphanius, De duodecim Gemmis in Veste Aaronis. Gr. Lat. cum<br />
corollario Gesneri. 8vo. Tig. 1565.<br />
Fabricius, (G.,) De metallicis rebus et nominibus obs. var. erud<br />
quibus. ea potissimum explicantur quse G. Agricola praeteriit. 8vo.<br />
Tiguri, 1566.<br />
Lemnius, (Levinus,) Occulta Naturae Miracula. 8vo. Antwerp, 1567.<br />
Mizaldus, (Anton.,) Memorabilium Utilium et Jucundorum Centuria<br />
IX. 8vo.
V 'APPENDIX. 467<br />
Cellini, (Benvenuto,) Del Arte del Gioiellare. 4to. Fior. 1568.<br />
Albert!, (Magni,) De Mineralibus et rebus metallicis. Libri V. 8vo.<br />
1541, 1569.<br />
Mizaldus, (Anton.,) Secrets de la Lune. Svo. Paris, 1571.<br />
Athenaeus, Deiphnosophistae, (Banquet des Pliilosopb.es,) traduit par<br />
Dalecbamp. Paris, 1573.<br />
Marbodaaus, (Gallus,) De Gemmarum Lapiduinque pretiosorum formis<br />
atque viribus opusculum. 8vo. Colon. 1593 ; 12mo. Ba#.<br />
1555 ; 12mo. Lubec, 1575.<br />
Belleau, (Rene,) Les Amours et nouveaux Changes des Pierres pre<br />
cieuses. 4to. Paris, 1576.<br />
Evax, (a King of the Arabs,) a MS. is attributed to him on the<br />
properties and effects of precious stones, published by Henry<br />
Rantzovius, under the title " De Gemmis scriptum olim a poeta<br />
quodam non infeliciter carmine redditum et nunc primum in lucem<br />
editum." 4to. Leipsic, 1585.<br />
Bacci, (Andrea,) Le XII. Pietre preziose.<br />
'<br />
4to. Roma, 1587.<br />
Cnesalpin, (A.,) De re metallica. 4to. Romce, 1596.<br />
Porta, (Giov. Baptista,) A Method of Knowing the Inward Virtues<br />
of Kings by Inspection. Fol. Neapoli, 1601.<br />
Arnobio, (Cleandre,) II Tesoro delle Gioie, trattato maraviglioso.<br />
Venet. 1602. ^<br />
Bacci, (Andrea,) De Gemmis et Lapidibus pretiosis, tractatus ex Ital.<br />
Lingua Lat. red. 8vo. Franco/, 1605.<br />
Fernel, (John Francis^) Pharmacia, cum Guliel. Plantii et Franc.<br />
Saguyerii Scholiis. 12mo. Hanov. 1605.<br />
Morales, (Gasp, de,) Libro de las Virtudes y Propriedades maravil-<br />
losas de las Piedras preziosas. 8vo. Madrid, 1605.<br />
Porta, (Giov. Baptista,) De DistiUationibus. 4to. Rome, 1608.<br />
Avicennaa Opera. Roma?, 1593. Venetiis, 1608.<br />
Ferrante Imperator : De fossilibus opusculum. 4to. Napoli, 1610.<br />
Portaleone, (Abraham,) Shilte Haggeborim. (The Shields of the<br />
Mighty.) Heb. Mantua, (A. M. 5372,) 1612.<br />
Clutius, (Augerius,) Calsvee, sive Dissertatio Lapidis Xephrititri, seu<br />
Jaspidis viridis, naturam, proprfetates, et operationes exhibens<br />
Belgice. 8vo. Amsterdam, 1621, et Lat. per Gul. Lauremberg,<br />
fil. 8vo. Rostochii, 1627.<br />
Bacci, (Andrea,) De Gemmis ac Lapidibus pretiosis in S. Scriptura.<br />
4to. Rome, 1577 ; 8vo. Franc. 1628.<br />
Jonstonus, (Johannes,) Thaumatographia Naturalis. 12mo. Amst.<br />
1632,
468 APPENDIX.* *<br />
Clave, (Estienne,) Paradoxes, ou Traittez PMlosopliiques desPierres<br />
et Pierreries, centre 1'opinion vulgaire. 8vo. Paris, 1635.<br />
Csesius, (Bernardus,) De Mineralibus. Fol. Lugduni, 1636.<br />
Toll, (Adrianus,) Gemmarum. et Lapidum Historia. 8vo. Lugduni,<br />
1636.<br />
Boot, (Anselmus Boetius de,) Gemmarum et Lapidum Historia. 4to.<br />
Hanover, 1690. Recensuit et commentariis illustravit Adr. Toll.<br />
8vo. Lugd, Batav. 1636.<br />
Boot, (Ans. Boe'ce de,) Le Parfaict Joaillier, ou Histoire des Pierreries,<br />
de nouveau enriclii de belles Annotations par Andre Toll, trad, du<br />
Lat. par J. Bachou. 8vo. Lyon, 1644.<br />
Toll, (Adr anus,) Le Parfaict Joiillier, ou Histoire des Pierreries, ou<br />
1 01 1 amplement descrites leur naissance, juste prix,<br />
Lyon, 1644.<br />
etc. 8vo.<br />
Laet, (Jo. de,) De Gemmis et Lapidibus, Lib. II. Gr. et Lat. Part*,<br />
1647.<br />
Ecchellensis, (Abraham,) Versio Durrhamani de Medicis Virtutibus<br />
animalium, plantarum et Gemmarum. 8vo. Pans, 1647.<br />
Habdarralimanus, (Asiutensis ^Bgyptius,) De Proprietatibus ac Virtutibus<br />
medicis Animalium, Plantarum ac Gemmarum, ex Arab.<br />
Lat. redd, ab Abrahamo Ecchellenst 8vo. Paris, 1647.<br />
Laet, (John de,) De Gemmis et Lapidibus Libri II., quibus prsemit-<br />
de Lapidibus Gr. Lat., cum Annotationi-<br />
titur Theophrasti Liber ;<br />
- bus. 8vo. Ludg. Bat. 1647.<br />
Boetius, (de Boot,) Gemmarum et Lapidum historia, quam olim<br />
edidit Ans. B. de Boot, postea Adrianus Tollins recensuit. Tertia<br />
Edit, longe purgatissima. Cui accedunt Jo. de Laet, de gemmis<br />
et lapidibus Libri II., et Theophrasti liber de Lapidibus. 8vo.<br />
Lugduni Batawrum, 1647.<br />
Paracelsus, (Philippus Aurelius Theophrastus,) Nine Books on the<br />
Nature of Things ; into English by J. F. 4to. London, 1650.<br />
Nichols, (Thomas,) Arcula Gemmea ; or, the Nature, Virtue and<br />
Valour of Precious Stones, with Cautions for those who deal in<br />
them. 4to. Cambridge, 1652.<br />
Nichols, (Thomas,) A Lapidary, Vr History of Pretious Stones ;<br />
with<br />
Cautions for the undeceiving of all those that deal with Pretious<br />
Stones. 4to. Cambridge, 1652.<br />
Hermes Trismegistus, Tabula Smaragdina vindicata. 12mo. 1657.<br />
Nichols, (Thomas,) Gemmarius Fidelis, or the Faithful Lapidary ;<br />
experimentally describing the richest Treasures of Nature, in an<br />
Historical Narrative of the several Natures, Virtues and Qualities
APPENDIX. 469<br />
of all Precious Stones, "with a Discovery of all such as are Adul-<br />
terate and Counterfeit. 4to. London, 1659.<br />
Lowell, (Robert,) Panzoologicomineralogia, or a History of Animals<br />
and Minerals. 12mo. Oxford, 1661.<br />
Johnson, (J.,) Notitia regni mineralis, sive Catalogus subterraneorum<br />
cum prsecipuis differentiis. 12mo. Lipsice, 1661.<br />
Berquen, (Robert de,) Les Merveilles des Indes Orientales et Occi-<br />
dentales, ou nouveau Traite des Pierres precieuses et des Perles.<br />
4to. Pflrw,.1661.<br />
Jonstonus, (J.,) Notitia Regni Yegetabilis et Mineralifl. 12mo. Lips.<br />
1661.<br />
Boyle, (Hon. Robert,) Experiments and Considerations upon Colour,<br />
with Considerations on a Diamond that Shines in the Dark. 8vo.<br />
London, 1663.<br />
Kircheri, (Athanasii,) Mundus subterraneus in Libros XII., digestus.<br />
With plates and portraits of Kircher and Pope Alexander.<br />
. Amsterdam, 1665.<br />
Fol.<br />
Histoire des Joyaux et des principales Richesses de 1'Orient et de<br />
1'Occideat. 12mo. Geneve, 1665.<br />
M. L. M. D. S. D., Denombrement, FacultS et Origine des Pierres<br />
precieuses. Post 8vo. Paris, 1667.<br />
Schmid, (Joachimus,) De Margaritis. 4to. Wtttebergce, 1667.<br />
Rhosnel, Le Mercure Indien. Paris, 1668.<br />
Piererus, (G. P.,) Lazulus, Dissertatio chymico-medica. 4to. Ar-<br />
gentarati, 1688.<br />
Aldrovandi, (Ulyssis,) Opera Omnia. 3 vols. fol. with several thousand<br />
wood cuts. B&nonice, 1599-1668.<br />
Tesoro deUe Gioie, Trattato Curioso. 12mo. Venetia, 1670.<br />
History of Jewels. 12mo. London, 1671.<br />
Steno, (Nicolaus,) Prodromus to a Dissertation concerning Solids<br />
naturally contained within Solids. London, 1671.<br />
Boyle, (Hon. Robert,) An Essay about the Origin and Virtues of<br />
Gems, with some Conjectures about the Consistence of the Matter<br />
of Precious Stones, etc. London, 8vo. 1672, and 12mo. 1673.<br />
Sandius, (Christopher,)* On the Origin of Pearls. Phil. Trans.<br />
1674.<br />
Tavernier, Voyages en Turquie, enj'erse et aux Indes. 4to. Paris,<br />
1676.<br />
Kircher, (Athanasius,) Mundus Subterraneus in XII. Libros digestus.<br />
Fol. Ainstellodami, 1678.<br />
Blumenberg, Dissertatio Medica de Succino. 4to. Jena, 1682.
470<br />
APPENDIX.<br />
Kirani, Kiranedes, et ad eas Rhyakini Koronides, sive Hysteria<br />
Physico-Medica. 12mo.. London, 1685.<br />
Konig, (Emanuel,) Regnum Minerale, physice, inedice, anatomice,<br />
alcliymice, analogice, tlieoretice et practice investigatum. 4to.<br />
Basil, 1687.<br />
Orpheus, (1260 B. C.,) Hymni et de Lapidibus, Gr. Lat., curante A.<br />
C. Eschenbachio ; accedunt H. Stepliani notae. 8vo. Traj. ad Rh.<br />
1689.<br />
Panthot, (Jean B.,) Trait e des Dragons et des Escarbqucles. Small<br />
12mo: Lyon, 1691.<br />
Hiaerne, (Urban,) Kort Anledning til askillige Malm och Bergarters,<br />
Mineraliers, etc. ; eftersporjande och angifvande. Stockholm, 1694.<br />
Hiller, (Matth.,) Tractatus de Gemmis XII. in Pectorali Pontificis<br />
Hebraeorum. 4to. Tubingen, 1698.<br />
Slevogtii, (J. H.,) De Lapide Bezoar. 4to. Jena, 1698.<br />
Venette, (Nicolas,) Trait6 des Pierres. 12mo. Amst. 1701.<br />
Strachan, Observations on Coral, large Oysters, Rubies, etc. Abr^<br />
ii. 711. Phil. Trans. 1701.<br />
Gulielmini, De Salibus dissertatio physica, medico-mechanica. Ve-<br />
netiis, 1705.<br />
Curiose Speculationen. Leipzig, 1707.<br />
of the Diamond. Phil. Trans. Abr. ii. 405. 1708.<br />
Description<br />
Chambon,<br />
1714.<br />
Traite des Metaux et des Mineraux. 12mo. Paris,<br />
Leisnerus, (Gott. Christ.,) De Coralliorum Natura, Proeparatis et<br />
Usibus. Wittembergw, 1720.<br />
Cappeller, (Maur. Ant.,) Prodomus Crystallographise, de Crystallis<br />
iinproprie sic dictis Commentarium. 4to. Lucernce, 1723.<br />
Henckel, (J. Fr.,) Pyritologia. 8vo. Lip&im, 1725.<br />
Woodward, (Dr. J.,) Fossils of all kinds digested into a method suitable<br />
to their mutual relation and affinity. With plates. London,<br />
1728.<br />
Woodward, (Dr. J.,) An attempt towards the Natural History of the<br />
Fossils of England, in the collection of J. Woodward. 8vo. Lon-<br />
don, 1729.<br />
Memoires de Regne de Catherine, Imperatrice de Russie. Amster-<br />
dam, 1729.<br />
Bourget, Lettres sur la Formation des Sels et Cristaux. 12mo.<br />
% Amst. 1729.<br />
Bromel, (Magn. von,) Inledning til nodig Kundskap om Bergarter,<br />
Mineralier, Metaller, samt Fossil ier. 8vo. Stockholm, 1730.
APPENDIX. 471<br />
Gimma," (D. Giacinto,) Delia Storia naturale dell^ Gemme, delle<br />
Pietre e di tutti Mineral!, owero della Fisica sotteranea. 4to.<br />
Napoli, 1730.<br />
Sarmento, (James Castro de, M. D.,) An Account of Diamonds found<br />
in Brazil. Phil. Trans. Abr. vii. 503. 1731.<br />
Henckel, (J. Fr.,) Idea generalis de Lapidum origine. 8vo. Dresd.<br />
et Lips. 1734.<br />
Colonne, (Francois Marie Pompee,) Histoire Naturelle de TUnivers.<br />
4 vols. 8vo. Paris, 1734.<br />
Pluche, (1'Abbe Antoine Noel de,) Spectacle de la Nature. 4to.<br />
Paris, 1732-39.<br />
Becher, (John Joachim,) Physica Subterranea. 4to. Lipsice, 1739.<br />
Argenville, Traite de 1'Oryctologie. Paris, 1740.<br />
Marbodaeus, De Lapidibus pretiosis Enchiridion, cum Scholiis Pic-<br />
torii. 4to. Wolfenbuttelce, 1740.<br />
Swedenborgii, (Emanuelis,) Opera Philosophica et Mineralia. 3<br />
vols. fol., with numerous plates. Paris, 1743.<br />
Argenville, (A. J. D. d',) De 1'Histoire Naturelle eclaircie dans deux<br />
de ses parties principales : la Lithologie et la Conchologie. 4to.<br />
Paris, 1743.<br />
Elliott, (John, F. R. S.,) on the Specific Gravity of Diamonds.' Phtt.<br />
Trans. Abr. ix. 147. 1745.<br />
St. Laurent, (Joanon de,) Description abregee du fameux Cabinet de<br />
M. le Chevalier de Baillon, pour servir a 1'histoire naturelle des<br />
Pierres precieuses, etc. Luques, 1746.<br />
Theophrastus, History of Stones, with the Greek Text and an English<br />
Version, and Notes Critical and Philosophical, including the<br />
Modern History of Gems described by that Author, by Sir John<br />
Hill. 8vo. London, m$.<br />
Kahler, (Mart.,) De Crystallorum Generatione. 4to. Upsal,174X.<br />
Henckel, (J. Fr.,) In Mineralogia redivivus. 8vo. Dresdw, 1747.<br />
Wallerius, (J. G.,) Mineralogia eller Mineral Ricket indelt och beskrifvet.<br />
8vo. Stockholm, 1747.<br />
Dingley, (Robert, Esq.,) On Gems and Precious Stones, particularly<br />
such as the Ancients used to engrave on. Phil. Trans. Abr. ix.<br />
345. 1747.<br />
Hill, (Sir 'John,) The History of Fossils. London, 1748.<br />
Leonardus, (Camillus,) The Mirror of Stones, in which the Nature,<br />
Generative Properties, Virtues and Various Species of more than<br />
200 different Jewels, Precious and Rare Stones are distinctly<br />
described. 8vo. London, 1750.
472 APPENDIX.<br />
Mariette, (P. J.^ Trait6 des Pierres gravies. Fol. Paris, 1750.<br />
Jeffries, (David, Jeweller,) Treatise on Diamonds and Pearls, in which<br />
their importance is considered, plain rules are exhibited for ascertaining<br />
the value of both, and the true method of manufacturing<br />
Diamonds is laid down. 8vo. 30 copper plates. Published by<br />
subscription. London, 1750-51 and 1753.<br />
Jeffries, (D.,) Trait6 des Diamants et des Perles. 8vo. . Paris, 1753.<br />
Pott, (M. J.,) Lithogeognosie, ou Examen chymique des Pierres et<br />
des Terres en general et de la Topaze et de la Steatite en particu-<br />
lier. 8vo. Paris, 1753.<br />
Jeffries, (David,) An Abstract of the Treatise on Diamonds and<br />
Pearls, by which the usefulness to all who are any way interested<br />
in these jewels will sufficiently appear, and therefore addressed to<br />
the nobility and gentry of this kingdom, and to the traders in<br />
jewels. 8vo. Baldwn, London, 1754.<br />
Natter, (Laurentius,) A Treatise on the Ancient Method of Engraving<br />
Precious Stones compared with the Modern. Fol. London,<br />
1754.<br />
Traite des Pierres _de Theophraste, trad, du Grec. 12mo. Paris,<br />
1754.<br />
Salerne, L'Oryctologie. 4to. Paris, 1755.<br />
Cartheuser, Elementa Mineralogise systematice disposita. 8vo. Fran-<br />
co/. 1755.<br />
Kalm, (P.,) Nagra Kannemarken til nyttiga Mineraliens eller ford<br />
och Baigarters upfinnande. 4to. Aboce, 1756.<br />
Da Costa, (E. Mendes,) Natural History of Fossils. 4to. London,<br />
1757.<br />
Pott, (J. H.,) Chemische tlntersuchungen, welche vornehmlich von<br />
der Litheognosie handeln. 4to. Potsdam, 1746 ; also 1751-54<br />
and 1757.<br />
Woltersdorf, (J. L.,) Systema minerale in quo regni mineralis producta<br />
omnia systematica per classes, ordines, genera, et species<br />
proponuntur. 4to. Berlin, 1738 ; also 1753-4, and 1755-8.<br />
Cronstedt, (Axel von,) Forsok til Mineralogia eller Mineral-rikets Upstallning.<br />
8vo. Stockholm, 1758.<br />
Bomare, (Valmont de,) Prospectus d'un cours surl'histoire.Naturelle<br />
des Mineraux. 12mo. Paris, 1759.<br />
Gerhard, (C. A.,) Disquisitio physico-chemica Granatorum Silesiae<br />
atque Bohemise. Inaug. Diss. 4to. Frankfurt a. d. Oder, 1760.<br />
Gronovii, (L. T.,} Bibliotheca Regni Animalis et Lapidei. 4to. Luyd.<br />
Bat. 1760.
APPENDIX. 473<br />
Natter, (Lgurentius,) Catalogue des Pierres gravies de Mylord Comte<br />
de Besborougli. 4to. London, 1761.<br />
Pouget, (N.,) Traite des Pierres precieuses, et de la maniere de les<br />
employer en parure. 4to. Paris, 1762.<br />
Vogel, (R. A. Praes.,) Terrarum atque lapidum partitio, resp. A. Fr.<br />
Hempel. 4to. Gdttingen, 1762.<br />
Walch, (J. E. J.,) Das Steinreich systematischentworfen. 2 vols.<br />
8vo. 24 plates. Halle, 1762.<br />
Bertrand, (E.,) Dictionnaire universel des fossiles propres<br />
et des<br />
fossiles accidentels, contenant une description des Terres Sables,<br />
&c. 8vo. 2 vols. in 1. La Haye, 1763.<br />
'Pheopliylacti Opera, a J. F. Bern, de Rubeis et Borif. Finettio,<br />
Greec. et Lat. 4 vols. Fol. Venet. 1754 and 1763.<br />
Justi, (J. H. G.,) Grundriss des gesammten Mineralreiclis.<br />
also in 1765.<br />
8vb.<br />
Gdttingen, 1757 ;<br />
Linnaeus, (C.,) Systema Naturae sive tria regna. Ed. I. Fol. Lugd..<br />
Bat. 1735. Ed. XII., Holmice, 1766.<br />
Bertrand, (E.,) Recueil de divers TraiteV sur 1'Histoire Naturelle de<br />
la Terre et des Fossiles. 4to. Avignon, 1766.<br />
Bock, (Fr. S.,) Vesucb einer kurzen Naturgeschicbte des Preussischen<br />
Bernsteins, und einer neuen warscbeinlichen Erklarung seines<br />
1767. '<br />
Ursprunges. 8vo. Kdnigsberg,<br />
Wallerius, (J. G.,) Lucrubrationum arademicarum specimen primum<br />
de systematibus mineralogicis et systemate mineralogico rite<br />
condendo. 8vo. Holmice, 1768. *<br />
Scopoli, (J. -A.,) Einleitung zur Kenntniss und Gebrauch der Fossilien.<br />
8vo. Riga und Milan, 1769.<br />
Baumer, (John Willi^ Historia Naturalis Lapidum preciosorum<br />
omnium, etc. 8vo. Franc. 1771.<br />
Bourguet, Du Regne Minerale. 4 vols. 12mo. Paris, 1771.<br />
Forster, (J. R.,) ClassiJBcation of Fossils and Minerals. London,<br />
1768 ; also in 1772.<br />
Scopoli, (J. A.,) Principia Mineralogiaa systematic^ et practical.<br />
Pragcs, 1772.<br />
Juwelier, Der Aufrichtige, oder Anweisung aller Arten Edelsteine,<br />
Diamanten, und Perlen zu erkennen, nebst einer aus dem<br />
Engliscben iibersetzten AbbandJung von den Diamenten und<br />
Perlen. 8vo. Frankfurt, 1772.<br />
Hodgson, (Rev. Jobn,) Dissertation on an Ancient Cornelian. ArcJwol.<br />
ii. 42. 1773.
474 APPENDIX.<br />
Bruckmann, (U. F. B.,) Abhandlung von Edelsteinen. Braunschweig,<br />
1757-73.<br />
Baiimer, (J. W.,) Naturgeschichte aller Edelsteine, wie auch der<br />
Erde und Steine, so bisher z'ur Artznei sind gebraucht worden.<br />
Aus dem Latein. von Karl, Freih. von Meidinger. 8vo. Wien,<br />
1774.<br />
Schroter, (J. S.,) Journal fiir die Liebhaber des Steinreichs. Weimar,<br />
1774.<br />
Werner, (Abr. G.,) Vender ausserlichen Kennzeichen der Fossilien.<br />
8vo. Leip. 1774.<br />
Bruckmann, (Fr. Hier.,) A Treatise on Precious Stones. 8vo. 1775.<br />
Born, (Baron Inigo,) Schneckensteine, oder die Sachsischen Topas-<br />
felsen. 4to. Prag. 1776.<br />
Collini, (Cosmus,) Journal d'un Voyage, qui contient differentes<br />
observations rnineralogiques, particulierement sur les agates, avec<br />
. un detail sur la maniere de travailler les agates. 8vo. Manrilieim,<br />
1776.<br />
Dutens, (Lewis,) Des Pierres precieuses et des Pierres fines, avec les<br />
moyens de les connoitre et de les valuer. Londres, 1776.<br />
Scopoli, (Jo.,) Ant. Crystallographia Hungarica. 4to. Prague, 1776.<br />
Vogel, (R. A.,) Practisches Mineralsystem. 2d ed. 8vo. Leip. 1776.<br />
Sage, Mineralogie docim'astique, with plates. 8vo. Paris, 1772 ;<br />
also in 2 vols. in 1777.<br />
Wallerius, (J. G.,) Systema Mineralogicum, quo Corpora Mineralia<br />
in classes, ordines, genera et species, suis cum va'r. divisa descri-<br />
buntur atque observationibus, experimentis et figuris illustrantur.<br />
2 vols. 8vo. Vindob.l.<br />
Bruckmann, (U. F. B.,) Gesammelte und eigane Beitrage zu seiner<br />
Abhandlung von Edelsteinen. Braunschweig, 1778.<br />
Bomare, (Valmont de,) Mineralogie, ou nouvelle exposition de Regne<br />
Minerale. 8vo. Pa/ris, 1769 ; also in 1774, 1780.<br />
Fichtel, (J. C. Von,) Mineralgeschichte. 4to., with plates. Ham-<br />
burgh, 1780.<br />
Haiiy, (Abbe de,) Traite de la Mineralogie. Paris, 1780.<br />
Regenbogen-Achat, Vom. 4to. Hamburgh, 1780.<br />
Gerhard, (C. A.,) Beitrage zur Chemie und Geschichte des Mmeral-<br />
reichs. 2 vols. 8vo. Berlin, 1773-1776 ', also in 1781.<br />
Lenz, (J. G.,) Tabellen iiber das gesammte Steinreich. 4to. Jena,<br />
1781.<br />
Bergmann, (T.,) Sciagraphia regni mineralis secundum principia<br />
proxuna digesti. 8vo. Lipsice, 1782.
APPENDIX. 475<br />
jjj<br />
Buchoz, Lee Dons merveilleux et diversement colories de la Nature<br />
dans le Regne Mineral. Fol. Para,. 1783.<br />
(^.rosi, (Johann,) Sur la Generation du Silex du Quarz. 8vo.<br />
Oracm. 1783.<br />
Rome de L'Isle, Essai de Cristallographie. 8vo. Paris, 1772. 2d<br />
ed. in 4 vols. 8vo. 1783.<br />
M. Buffon, (Le Comte de,) Histoire Naturelle des Mineraux. 4to.<br />
Paris, 1783.<br />
Faujas de Saint Fond, (B.,) Mineralogie des Volcans ou Description<br />
de toutes les substances produits ou rejetees par les feux souter-<br />
rains. Royal 8vo. Paris, 1784.<br />
Daubenton, Tableaux methodiqtie des Mine'raux suivant leurs differentes<br />
natures. 4to. Paris, 1784.<br />
Ravius, (S. F.,) Specimen Arabicum, continens descriptionem et ex-<br />
cerpta libri Achmedis Teifascbii ' De Gemmis et Lapidibus Pre-<br />
tiosis/ Arabic. Trapetum ad Rhenum, 1784.<br />
Haiiy, (Rene Just.,) Essay d'une Theorie BUT la structure des Cristaux.<br />
8vo. Paris, 1784.<br />
:<br />
-<br />
Cadet, (Le Jeune,) Memoire sur les Jaspes et autres Pierres precieuses<br />
de 1'ile de Corse, etc. 8vo. Bastia, 1785.<br />
Genuine Account of the present state of the Diamond Trade in the<br />
Dominions of Portugal, with some authentic pieces, in a letter<br />
from a merchant in Lisbon to his Correspondent in London. 4to.<br />
L
476 APPENDIX.<br />
De Born, Catalogue de la collection des Fossiles de Eleonore de<br />
Raab. 2 vols. 8vo. Vienna, 1790.<br />
Lenz, (J. G.,) Mineralogisclies Handbucli durch weitere Ausfuhrui%<br />
des Wernerschen Systems. 8vo. Hildburghausen, 1791.<br />
Catalogue des Bijoux nationaux. Paris, 1791.<br />
Lehman, (J. A.,) Entwurf, einer Mineralogie.<br />
1857 also in 1769 and 1791.<br />
;<br />
8vo. Frank/, et Leip.<br />
Gallitzin, (Le Prince Dimitri de,) Traite ou Description abregee<br />
methodiques' des Mineraux. 4to. Maastricht, 1792.<br />
Emmerling, (L. A.,) Lehrbuch der Mineralogie. 8vo. Giezen, 1793.<br />
Veltheim, (A. V. von,) Reformen in der Mineralogie. 8vo. Helm.<br />
1793.<br />
Bekkerheim, (Karl,) Krystallographie des Mineralreichs. 8vo. Wien,<br />
1793.<br />
Veltheim, (A. F. von,) Etwas iiber Memnons Bildsaule, Nero's<br />
Smaragd, Toreutik, und die Kunst der Alten in Stein und Glas<br />
zu sclmeiden. 8vo. Helmstadt, 1793.<br />
Wulfinii Descriptlo Helmintholiti pulcherrimi versicoloris in marmore<br />
Corinthiaco. 4to. Erlangce, 1794.<br />
Lenz, (J. G.,) Vollstandig Einleitung zur Kenntniss der Mineralien.<br />
2 vols. 8vo. Leipz. 1794.<br />
Kirwan, (R.,) Elements of Mineralogy. 8vo. London, -1784 ; 2d<br />
ed. 1794.<br />
Schmeisser, (J. G.,) System of Mineralogy. Vol. 1. 8vo. London,<br />
1794.<br />
Wiedenmann, Handbuch der Oryktognostichen Theils der Mineralo-<br />
1794. .<br />
gie. 2 vols. 8vo. Leipzig,<br />
Del Rio, (Don Andres Manuel,) Elementos de Oryktognosia 6 del<br />
conocimiento de los fossiles, dispuestos segun los principios de A.<br />
G. Werner. .4to. Mexico, 1795.<br />
Retzius, (A. J.,) Forsok til Mineral-Rikets Upstallning.<br />
1795.<br />
8vo. Lund.<br />
Forster, (J. R.,) Onomatologia nova systematis oryktognosise, voca-<br />
bulis latinis expressa. Fol. Halce, 1795.<br />
Psellus, )Michael Cohstantinus,) De Lapidum Virtutibus, Gra3ce ac<br />
Latine. 8vo. Lugduni Batavorum, 1795.<br />
^abington, (Charles,) A Systematic Arrangement of Minerals, their<br />
Chemical, Physical, and External Characters. 4to. London, 1795.<br />
Ekeberg, (Andrew Gustavus,) Dissertatio de Topazio. Ifpsal, 1796,<br />
Hasse, (J. H, F..) Der Aufgefundene Eridanus, oder neue Aufsch-<br />
lus,se iiber den Ursprung des Bernsteins. 8vo. Riga, 1796.
APPENDIX. 477<br />
Napione, Element! di Mineralogia. 8vo. Turin, 1796.<br />
Gerhard, (G. A.,) Grundriss des Mineralsystems. 8vo. Berlin,<br />
1786 and 1797.<br />
Andrada, (M. d',) An Account of the Diamonds of Brazil. Nich.<br />
Journ i. 24 1797.<br />
*<br />
Diamond, The, or the Pest of a Day. Fores. 4to. London, 1797.<br />
Tennant, (Smithson, Esq., F. R. S.,) On the Nature of the Diamond.<br />
Phil.Trans 1797, xviii 97, and Nich. Journ. i. 177. 1797.<br />
Veltheim, (A. F. von,) Etwas iiber das Onyx-Gebirge des Clesias<br />
1 797.<br />
und den Handel der Alten nach Ost-Indien. 8vo. Helrwtadt,<br />
Bouruon, (Count de,) An Analytical Description of the "Crystalline<br />
.Forms of Corundum from the East Indies and China. Phil.<br />
Trans. At>r. xviii 368. 1798.<br />
Struve, (H.,) Methode Analytique desFossiles, fondee surleurs Carac-<br />
teres Exterieurs. 8vo. Lausanne, 1797 ; 8vo. Paris, 1798.<br />
Townson, (R.,) Philosophy of Mineralogy. 8vo, Plates. London,<br />
1798.<br />
Reuss, (F. A.,) Lexicon Mineralogicum, sive Index Latino-Gallico-<br />
Suecico-Danico-Angnco-Russico-Hungarico-Germanicus Minerali-<br />
*mn. 8vo. Cura Regis. Leip. 1798.<br />
GreviUe, (Rt. Hon. Charles, F. R. S.,) On the Corundum Stone from<br />
Asia. Phil.- Tram. Abr. xviii. 356, 1798, and NicJi. Journ, ii, 477.<br />
1799.<br />
Guyton-Morveau, (B. L.,) Verbal Process of the conversion of Soft<br />
Iron into Cast Steel by means of the Diamond. Nich. Journ. iii.<br />
353. 1799.<br />
Klaproth, (Martin Henry,) Analysis of the Spinel. Nich. Journ, iii.<br />
549. 1799.<br />
Palm, (J. J.,) Dissertatio gradualis sistens observationes nonnullas<br />
de Lapide Obsidiano. 4to. Londoni Gothorum, 1799.<br />
Babington, A Systematic Arrangement of Minerals. 4to. London,<br />
1795 ; 1799.<br />
Batsch, (A. J. G. K.,) Versuch einer Anleitung zur Kenntniss und<br />
Geschiehte der Thiere und Mineralien. 2 Bde. 8vo. Jena, 1788,<br />
1789 ;<br />
also 1796-1800.<br />
Jameson, (Robert,) Mineralogy of the Scottish Isles. Maps and<br />
Plates. 2 vols. 4to. Edinburgh, 1800.<br />
Brunner, (J.,) Versuch einer neuen Systems der Mineralogie. 8v r o.<br />
Leipzig, 1800.<br />
Blindheim, (J. J.,) Ueber den Sibirischen und Taurischen Kalzedon.<br />
Neue Schrift. der GeseUsch. naturf. Freunde. 4to. Berlin, 18CO.
478 APPENDIX.<br />
Mackenzie, (Sir Geo. Stewart, Bart., F. R. S. L. & E.,) Experiments<br />
on the Combustion of the Diamond, the Formation of Steel by its<br />
Combination with Iron, etc. Nich. Journ. iv. 103. 1800.<br />
BournoH, (Count de,) Description of the Corundum Stone, and its<br />
Varieties commonly known as Oriental Ruby, Sapphire/ e.tc. Phil.<br />
Trans, p. 223. 1801.<br />
Kohler, (H. K. A. von,) Untersuchung iiber den Sard, Onyx, und<br />
Sardonix. 8vo. Braunschweig, 1801. '<br />
,-V<br />
Ur, (Fr. Ben.,) Ueber den Sarder Onyx und Sardonyx ; also, Nach-<br />
trag iiber, etc., 1804. Braunschiceig, 1801.<br />
Hoff, (A. von,) Magazin fur die gesammte Mineralogie, &c., pi.<br />
Leipz. 1801.<br />
8vo.<br />
Haiiy, (L'Abbe,) Traite de Mineralogie. 8 vols. 8vo. Paris, 1801-2.<br />
Mawe, Mineralogy of Derbyshire. 8vo. Plates. London,. 1802.<br />
Dolomieu, (D. de,) Sur la Philosophic Mineralogique et sur Fespece<br />
Mineralogique. 8vo. Paris, 1802.<br />
Klaproth, (Martin Heinrich,) Beytrage zur Chemischen Kenntniss<br />
der Mineralkorper. 3 B. 8vo. Berlin, 1795-1802.<br />
Biehle, (Von,) Ueber die Bernstein-Grabereien in Hinter-Pommeru.<br />
8vo. Berlin, 1802.<br />
Chenevix, (Richard, Esq., F. R. S.,) Analysis of Corundum and some<br />
Substances that accompany it. Phil. Trans, p. 327. 1802.<br />
Haiiy, Memoire sur les Topazes du Bresil. Ann. du Mus. Paris,<br />
1802.<br />
Schwarze, (Christ. Aug.,) De Smaragdo Veterum. 4to. Gorlicii, 1802.<br />
Lenk, (J.,) Neue Entdeckung eines Steines Serpentin-Agat. Wie?i,<br />
1802.<br />
Gregor, (Rev. William, M. A.,) An Analysis of a variety of the Corundum.<br />
Nich. Journ. iv. 209. 1803.<br />
Schwarze, (Christ. Aug.,) De quodam Pseudo-Smaragdorum apud<br />
veteres genere. 4to. Gorlicii, 1803.<br />
Hausmann, (J. F. L.,) Krystallogische Beitrage. 4to. PL 1803.<br />
Ludwig, (C. F.,) Handbuch der Mineralogie nach A. G. Werner.-<br />
8vo. Leipzig, 1803.<br />
Lucas, (J. A. H.,) Tableau Methodique des especes minerales. 8vo.<br />
Paris and Strasb. 1803.<br />
Schwarz, (G. M.,) Handbok i Oryktognosien.<br />
Launnas, (L. de,) Mineralogie<br />
8vo. 1803.<br />
and Paris, 1803.<br />
des Anciens. 2 vols. 8vo. Bruxelles<br />
Rozin, Essai sur Fetude de la Mineralogie. 8vo. 368 pp. Bruxelles,<br />
1803.
APPENDIX. 479<br />
Mohs, (Priederich,) Handbuch der Oryktognosie. 3 vols. 8vo. Wien,<br />
1804<br />
Accmn, (F.,) Elements of Crystallography, after the manner of Haiiy.<br />
8vo. plates. London, 1804.<br />
Accum, (F.,) Analysis of Minerals. 12mo. London, 1804.<br />
Suckow, Anfangsgriinde der Mineralogie. 8vo. Leipzig, 1790 ; 2d<br />
ed. 2 vols. 8vo. 1803-4.<br />
Haberle, (C. C.,) B^eobachtungen<br />
iiber die Gestalt der Grand und<br />
Keimkrystalle des schorlartigen Berylls, nnd dessen iibrige.<br />
oryctognostiche und geognostische Verhaltnisse. Erfurt, 1804.<br />
Meineke, (J. L. G.,) Ueber den Chrysopras und die denselben begleitenden<br />
Fossilien in Schlesien. 4to. Erlangen, 1805.<br />
Jameson, (Robert,) A Treatise on the External Characters of Minerals.<br />
8vo. Edinburgh and London, 1804-1805.<br />
Haberle, (C. C.,) Beitrage zu einer allgemeinen Einleitung in das<br />
Studium der Mineralogie. 8vo. Weimar, 1805.<br />
Haberle, (C. C.,) Characterisirende Darstellung der Mineralien mit<br />
Hinsicht auf Werner et Hauy's beobachtungen. 8vo. Weimar,<br />
1806.<br />
Reuss, (F. A.,) Lehrbuch der Mineralogie nach Karsten's Tabellen.<br />
8vo. Leipzig, 1801-1806.<br />
Flade, (C. G.,) De Re Metallica Midianitarum et Phoenicorum. 4to.<br />
Leipzig, 1806.<br />
Berzelius, (J. Jacob, M. D., F. S. A.,) On the Composition of the<br />
Topaz, etc, Nich. Journ. ix. 105. 1807.<br />
Brongniart, Traite de Mineralogie, avec application aux Arts. Paris,<br />
1807.<br />
Eckennan, (N.,) Electra, oder die Entstehung des Bernsteins. 4to.<br />
Halle, 1807.<br />
Pepys, (William Hasledine, Treasurer of the Geol. Soc.,) On the<br />
Quantity of Carbon in Carbonic Acid, and on the Nature of the<br />
Diamond. Phil. Trans, p. 267, and Nich. Journ. xix. 267. 1807.<br />
Brochant de Villiers, (A. J. M.,) Traite Elementaire de Mineraux<br />
suivant les principes de Werner. 2 vols. 8vo. Paris; also 1807.<br />
Leonhard, (C. C.,) Taschenbuch fur die gesammte Mineralogie mit<br />
Hinsicht auf die neueste Entdeckungen. 8vo. 1807.<br />
Accum, (F.,) Manual of Analytical Mineralogy. 2 vols. PI. London,<br />
1808.- ^<br />
Karsten, (D. L. G.,) Tabellarische Uebersicht der mineralogischen<br />
einfach.en Fossilien. 8vo. 2te. Aufg. Berlin, 1792 ; also 1800,<br />
1808.<br />
'
480 APPENDIX.<br />
Bournon, (Le Comte de,) Trait e de la Chaux Carbonate et do<br />
1'Arragonite, auquel on a joint une introduction a la Mineralogie<br />
en general, une Theorie de la Crystallisation et son Application.<br />
4to. Londres, 1808.<br />
Brard, (C. P.,) Traite des Pierres precieuses. Paris, 1808.<br />
Haiiy, Sur la Reunion de la Pycnite avec le 1808.<br />
Topaze. 4to. Pans,<br />
Gautier, (J.,) Untersuchung fiber die Entstehung^, Bildung und den<br />
Bau des Cbalcedons, etc. Jena, 1809.<br />
Hausmann, (J. F. L.,) Entwurf eines Systems der unorganisirten<br />
Naturkorper. 8vo. Cassel, 1809. .<br />
Weiss, De indagando formarum crystallinarum cliaractere geometrico<br />
principal!. Lipsice, 1809.<br />
Lenz, (J. G.,) System der Mineralkorper. 8vo. also in 1809.<br />
Bamberg<br />
1800 ;<br />
und Wurzb.<br />
Petzl, (J.,) Ueber den glatten'Beryll von Rabenstein im Bayrischeri<br />
Walde. Abb. der Kon. Akad. 4to. Munchen, 1809-1810.<br />
Guyton-Morveau, (B. L.,) On the singular Crystallization of the<br />
Diamond. Nich. Journ. xxv. 67. 1810.<br />
G lithe, (J. M.,) Ueber den Asterios-Edelstein des Cajus Pliniiis<br />
Secundus ; eine antiquarisch-lithognostische Abhandlung. 4to.<br />
Munchen, 1810.<br />
Fischer, (G.,) Essai sur la Turquoise et sur la Calaite. Moscou,<br />
1810.<br />
Accum, (F.,) System of Mineralogy and Mineralogical Chemistry.<br />
4 vols. 8vo. London, 1810.<br />
Dree, (Marquis de,) Catalogue de Musee Mineralogique. 4to. Paris,<br />
1811.<br />
Maculloch, (John, M. D., F. 'L. S.,) Remarks on. Several Parts of<br />
Scotland which exhibit Quartz Rocks, and on the Nature and<br />
Connection of this Rock in general. Geol. Trans, i. 450. 1811.<br />
Chenevix, (R.,) On Mineralogical Systems. 8vo. London, 1811.<br />
Silliman, (B.,) Mineralogy and Geology of New-Haven, in a statistical<br />
account of the City of New-Haven, by Pres. Timothy Dwight,<br />
published by the Connecticut Academy of Arts and Sciences.<br />
New-Haven, 1811.<br />
8vo.<br />
Niizlein, (F. A., Versuch eine neuen Systems der mineralogischeinfachen<br />
Fossilien. Bamberg and Wurzburg, 1810, 1812.<br />
Lenz, (J. G.,) Erkenntnisslehre der Anorganischer Naturkorper.<br />
Giesen, 1813.
APPENDIX. 481<br />
Lucas, (J. A. H.,) Tableau Methodique des Especes Minerales. 8vo.<br />
Paris, 1806-1813.<br />
Bournon, (Comte de,) Catalogue de sa collection Mineralogique. 8vo.<br />
with 4to. plates. 1813.<br />
Mawe, (John,) A Treatise on Diamonds and Precious Stones, in-<br />
cluding their History, Natural and Commercial. To which is<br />
added some account of the best method of cutting and polishing<br />
them. 8vo. London, 1813.<br />
Brewster, (Sir David,) On the Optical Properties of Sulfuret of Car-<br />
bon, etc., with Inferences respecting the Structure of Doubly-refracting<br />
Crystals. Fol. Edinb. 1814.<br />
Davy, (Sir Humphry,) Prof, of Chem., etc., etc., Some Experiments<br />
on the Combustion of the Diamond and other Carbonaceous Sub-<br />
stances. Phil. Tram. p. 557. 1814.<br />
Aiken, (Arthur,) Manual of Mineralogy. 8vo. London, 1814.<br />
Allan, Mineralogical Nomenclature. 8vo. London, 1814.<br />
Gravenhorst,(J.L.C.,) Handbuchder Anorganognosie. 8vo. Leipzig,<br />
1815.<br />
Berzelius, (J. J.,) Versuch durch Anwendung der elektrisch chemischen<br />
Theorie und der chemischen Verhaltnisslehre, ein rein wiseenchaftliches<br />
System der Mineralogie zu begriinden. Aus dem<br />
Schwed von Dr. A. F. Gehlen. 8vo. Niirnberg, 1815.<br />
*Aikin, (A.,) Manual of Mineralogy. 12mo. Philadelphia, 1815.<br />
Bournon, (C. de,) A Descriptive Catalogue of Diamonds in the Cabinet<br />
of Sir Abraham Hume. 4to. London, 1815.<br />
Brewster, (Sir David,) On a New Optical and Mineralogical Property<br />
of Calcareous Spar. 4to. Edinb. 1815.<br />
Hauy, Observations sur les Tourmalines, particulierement sur celles<br />
qui se trouvent dans les Etats-TJnis. Mem. du Mus. Paris, 1815.<br />
John, (J. F.,) Naturgeschichte des Succins, oder des sogenannten<br />
Bernsteins. 8w>. Koln, 1816.<br />
Swedenstierna, (E. T.,) An Account of the Swedish Corundum, from<br />
Gellivara, in Lapland. Geol. Trans, iii. 415. 1816.<br />
Svedenstjerna, (E. Th.,) Ueber den Korund zu Gellivara in Lapland,<br />
ubersetzt von Dr. Hessel. Leonh. Taschenb. Frankfurt-a.-N. 1816.<br />
Berzelius, (J. J.,) Neues System der Mineralogie, aus dem Schwedischen<br />
von Dr. Gmelin und Pfaff. 8vo. Nurnberg, 1816.<br />
* Reprinted foreign works arc indicated by an asterisk.
482 APPENDIX.<br />
Tondi, Element! di Orittognosia. 2 vols. 8vo. Napoli, 1817.<br />
Haiiy, (L'Abbe,) Trait e des caracteres physique des pierres. 8vo.<br />
figs. Paris, 1817.<br />
Sowerby, Britisli Mineralogy. 8vo. London, 1802-1817.<br />
Leonhard, (C. C.,) R. F. Menz, und J. H. Kopp, Systematisch-Tabellarische<br />
Uebersiclit und Characteristik der Mineralkorper. 2 vols.<br />
Fol. Frankfort, 1806 ; 2d edit. 1817.<br />
*Phillips, (Wm.,) Outlines of Mineralogy and Geology. 12mo. New-<br />
York, 1817.<br />
Zappe, Mineralogische Abliandlungen. Wien, 1817.<br />
Haiiy, (Rene Just.,) Traite des Caracteres physiques des Pierres precieuses,<br />
pour servir a leur determination lorsqu'elles sont taillees.<br />
8vo. Paris, 1817.<br />
Brewster, (Sir David, LL. D.,F.R. S. L.etc,,) On the Optical Properties<br />
of Muriate of Soda, Fluate of Lime, and the Diamond, as ex-<br />
hibited in their action upon Polarized Light. Phil. Trans, viii.<br />
. 157. 1817.<br />
Brewster, (Sir David,) t)n the Effects of Compression and Dilatation<br />
altering the Polarizing Structure of Doubly-refracting Crystals.<br />
4to. Edirib. 1818.<br />
Carton, (J.,) Englischer Juwelier, Kenntniss, Werthund Preisschatzung<br />
aller Edelsteine, Perlen und Corallen, ins Deut. iibersetzt<br />
nach der 10 ed. 12mo. Ordtz, 1818.<br />
Fisher, (G. de Waldheim,) Essai sur la Pellegrina, ou la Perde Incomparable<br />
des freresZozima. Pamp. Hist. Nat. 8vo. Moscou,<br />
1818.<br />
Teifascite, (Ahmed,) Fior di Pensieri sulle Pietre Preziose, opera<br />
stampata nel suo originale Arabo di Ant. RainSri. 4to. Firenze,<br />
1818.<br />
Jameson, (Robert,) System of Mineralogy. 2 vols. pi. 8vo. Edin-<br />
&wr^,1804; 2ded. 1816; 3d ed. 1818.<br />
Hoffmann, (C. A. E.,) Handbuch der Mineralogie mit Fortsetzung von<br />
A. Breithaupt. 4 vols. Freylerg, 1811-1818.<br />
^Phillips, (Wm.,) Elementary Introduction to the Knowledge of<br />
Mineralogy, with notes and additions on American Articles, by<br />
Samuel L. Mitchijl. 12mo. New-York, 1818.<br />
Dana, (James Freeman,) Outlines of the Mineralogy and Geology of<br />
Boston and its environs. 8vo. Boston, 1818.<br />
*Thomson, (Thomas,) System of Chemistry, in 4 vols. Svo., the 3d<br />
containing a Treatise on Mineralogy. Edited by Thomas Cooper,<br />
from the 5th London edition. PMladelphia, 1818.
APPENDIX. 483<br />
Bakewell, (R.,) Introduction to Mineralogy. 8vo. London, 1819.<br />
Schoolcraft, (Henry R.,) A view of the Lead Mines of Missouri,<br />
including observations on the Mineralogy, Geology, Geography,<br />
&c., of Missouri and Arkansaw, and other portions of the Western<br />
Country. 2 plates, 300 pp. 8vo. New-York, 1819.<br />
Fladung, Versuch iiber die Kennzeichen der Edelsteine und deren<br />
vortheilhaftesten Sclinitt. Pesth, 1819.<br />
Brochant de Villiers, (A. J. M.,) Sur la cristallisation geometriquement<br />
et physiquement consideree. With numerous plates. 8vo.<br />
Strasburg, 1819.<br />
Frischholz, (J.,) Lehrbuch der Steinschneidekunst, fur Steinschneider,<br />
Graveurs, etc., und jedens welcher sich iiber die Veredlung der<br />
Steine zu unterrichten wiinscht. Mvnchen, 1820.<br />
Harris, (Thaddeus M.,) The Natural History -of the Bible, or a<br />
description of all the quadrupeds, birds, fishes, &c., precious stones,<br />
&c., mentioned in the Bible. 476 pp. 8vo. Boston, 1820.<br />
Hausmann, (J. F. L.,) Untersuchungen iiber die Formen der leblosen<br />
Natur Ir. Bd. 4to. mit vielen Kupfern. Gottingen, 1821.<br />
Mohs, (Friederich,) Die Charaktere der Classen, Ordnungen, Geschlechten<br />
und Arten, oder die Charakteristik der naturhistorischen<br />
Mineral-systems. 8vo. Dresden, 1821.<br />
Brard, (C. P.,) Mineralogie appliquee aux arts. 3 vols. 8vo. Paris, 1821.<br />
Berzelius, (J. J.,) Von der Anwendung des Lothrohrs in der Chemie<br />
und Mineralogie Aus der Handschrift ubersetzt von Heinr. Rose.<br />
;<br />
8vo. Number g, 1821.<br />
Berzelius, (J. J.,) The same, translated by J. G. Children. 8vo. 3<br />
pi. London, 1822.<br />
Kick, (Z.,) Tentamen JVIineralogicum, seu Mineralium nova distributio<br />
in classes, ordines, genera, &c. 8vo. BruxeUes, 1821.<br />
Koratz, (Michel,) Lexicon Mineralogicum enneaglottum. 8vo. Pest.<br />
.<br />
1821.<br />
Haiiy, (L'Abbe,) Traite de CrystaUographie. 2 vols. 8vo. Perns, 1822.<br />
Haiiy, (L'Abbe,) Traite de Mineralogie. 4 vols. 8vo. Paris, 1822.<br />
Cleaveland, (Parker,) Elementary Treatise on Mineralogy and Ge-<br />
ology. 670 pp. 8vo. Boston, 1816 ; 2d edit, in 2 vols. 8vo. Boston,<br />
1822.<br />
*Lowry, (Delvalle,) Conversations on Mineralogy and Geology.<br />
Philadelphia, 1822.<br />
Blumhof, (J. C.,) Lehrbuch der Lithurgik. Frankfurt, 1822.<br />
Cohen, (M.,) Beschreibendes Verzeichniss einer Sammlung von Diamanten.<br />
Wien, 1822.
484 APPENDIX.<br />
Mackenzie, (Sir G. S.,) On tlie Formation of Chalcedony. 4ta PMl.<br />
Trans. London, 1832.<br />
Partsch, (P.,) Besclireibendes Verzeichniss einer Sammlung von<br />
Diamenten und der zur Bearbeitung derselben nothwendigen Apparate,<br />
etc. Wien, 1822.<br />
Neumann, Beitrage zur Kristallonomie. 8vo. Berlin, 1823.<br />
Kosk, (M. F.,) Beitrage zur Kenntniss krys tallin Huttenproducte.<br />
8vo. Gdttingen, 1823.<br />
Breithaupt,*(A.,) Vollstandige Charakteristik des Mineral-systems.<br />
8vo. Dresden, 1823.<br />
Renier, (S. A.,) Element! di Mineralogia. 8vo. Padua, 1823.<br />
Phillips, (Wm.,) An elementary introduction to the knowledge of<br />
Mineralogy. 8vo. London, 1823.<br />
Bellerinan, (J. J.,) Die Urim und Thummin. Berlin, 1824.<br />
Glocker, (Ernst Friedrich,) De Gemmis Plinii, imprimis de Topazio.<br />
8vo. Vratislaviai (Breslau,) 1824.<br />
Brongniart, (Alex.,) Introduction a la Mineralogie. 8vo. Paris,<br />
1801 ; 2d edit, in 1824.<br />
Brard, (C. P.,) Manuel du Mineralogiste. 12mo. Paris, 1808 ; 3d<br />
edit. 1824.<br />
Steffens, Vollstandiges Handbuch der Oryktognosie. 4 vols. 8vo.<br />
Halle, 1811-1824.<br />
Stchegloff, (N.,) Mineralpguia po sistemie Gospodinda Haiiy. 2<br />
vols. 8vo. St. Petersburg, 1824.<br />
Webster, Catalogue of Minerals in .the State of New-York.<br />
Albany,<br />
12mo.<br />
1824.<br />
Hall, (Frederick,) Catalogue of Minerals found in the State of Vermont,<br />
and in the adjacent States. 44 pp. 8vo. Hartford, 1824.<br />
Robinson, (Samuel,) Catalogue of American Minerals, with their<br />
localities} arranged in the order of the States. 8vo. 316 pp.<br />
Boston, 1825.<br />
Haidinger, (Wm.,) Treatise on Mineralogy, or the Natural History<br />
of the Mineral Kingdom ; translated from the German of Mohs.<br />
3 vols. 8vo. Edinburgh, 1825.<br />
Monticelli and Covelli, Atlaute della Mineralogia Vesuviana.<br />
Napoli,<br />
19 pi.<br />
1825.<br />
Marx, (Dr. C. M.,) Geschichte der Krystallkunde.<br />
und Baden, 1825.<br />
8vo. Carlsrulie<br />
Ragoumovsky, (Greg. Comte de,) Distribution Technique des Pierres<br />
precieuses, avec leurs Caracteres distinctifs. 8vo. Vienne, 1825.
APPENDIX. 485<br />
Rose, (G.,) Ueber den Felspath, Labrador, etc., Gilbert, Ann. Leipzig,<br />
1826.<br />
Leonhard, (C. C.,) Handbnch der Oryctognosie. 8vo. Heidelberg,<br />
1821 ; 2d edit. 1826.<br />
Phillips, (Wm.,) Outlines of Mineralogy and Geology. 3d edit. 8vo.<br />
London, 1818 ; 4th edit. 1826.<br />
Naumann, (G. FT.,) Entwurf der Lithurgik oder okonomischen<br />
Mineralogie. 8vo. Leipzig, 1826.<br />
Rau, (Ambros,) Lehrbuch der Mineralogie. 8vo. Wurzberg, 1826.<br />
Girardin et Lecoq, Elemens de Mineralogie appliquee aux science<br />
chimique. 2vols. 8ro.pl. Paris, 1826.<br />
Drapiez, Mineralogie Usuelle, 504 pp. 12mo. Paris, 1826.<br />
Blum, (J. R.,) Verzeichniss der geschnittenen Steine indem Konigl.<br />
Museum zu Berlin. 8vo. Berlin, 1827.<br />
Del Rio, (Don Andres Manuel,) Nuevo sistema M nerale. Mexico,<br />
1827. -,><br />
Bredsdorf, (J. H.,) De notione speciei in regno minerali. 104 pp.<br />
12mo. Copenhagen, 1827.<br />
Desnos,(J. O.,) Precis de Mineralogie Moderne. 2 vols. 32mo.pl.<br />
formant20 et 21 livr. de TEncyclopedique portative. Paris, 1827.<br />
Glocker, (Dr.,) Grundriss der Mineralogie. 8vo. Bredau, 1827.<br />
Bernhardi, Beitrage zur Kenntniss der Cristallformen. Erfurt<br />
1827.<br />
Comstock, (J. L.,) Elements of Mineralogy, adapted to the use of<br />
Seminaries and private students. Ixxvi. and 338 pp. 8vo. Bos-<br />
ton, 1827 ; 2d edit. 12mo.<br />
Beumenberger, (J. G.,) Der Volkommene Juwelier. Weimar, 1828.<br />
Corsi, (Faust,) Delle Piedre antiche libri quattro. Roma, 1828.<br />
Fladung, (J. A. F.,) Edelsteinkunde. Sm. 8vo. Wien, 1828.<br />
Hausmann, (J. F. L.,) Handbuch der Mineralogie. 3 vols. 8vo.<br />
Gottingen, 1813 ; 2d edit. 1828.<br />
Breithaupt, (A.,) Physiotegie der Unorganischen Natur. 8vo. pi.<br />
Dresden, 1828.<br />
Blondeau, Manuel do Mineralogie. 18mo. Paris, 1825 ; 2d edit.<br />
1828.<br />
Naumann, (C. Fr.,) Lehrbuch der Mineralogie. 8vo. Berlin, 1828.<br />
Freisleben, (J. Ch.,) Magazin fur die Orictographie von sachsen.<br />
8vo. Freib&rg, 1828.<br />
Ermann, Beitrage zur Monographie des Marekasit, Turmalin und<br />
Brasilianischen Topas. From the works of the Berliner Akad.<br />
4to. Berlin, 1829.
486<br />
APPENDIX.<br />
Breithaupt, (A.,) Das Gesclileclit der Rhomboedrischen Turrnaline.<br />
Schweizzers Jahrbmh fur Chym. und Phys. 8vo. 1829.<br />
Glocker, (Dr.,) Uebersiclit der Krystallisations-systeme, etc. 48 pp.<br />
4tb. Breslau, 1829.<br />
Glocker, (Dr.,) Handbuch der Mineralogie fiir Vorlesungen und zum<br />
Privategebrauch bestimmt. 1829.<br />
Grasman, (J. Gunter,) Zur physischen Krystallonomie, und geometrischen<br />
Combinationslehre. 8vo. 184 pp. 3 pi. Stettin, 1829.<br />
Frankenheim, (M. L.,) De Cristallorum cohaesipne. Breslau, 1829.<br />
Haidinger, (Wm.,) Anfangsgrunde der Mineralogie. 15 pi. Leipzig,<br />
1829.<br />
Finder, De Adamante Commentatio Antiquaria. Berlin, 1829.<br />
Macauley, (James,) A sketch of the Geology and Mineralogy of the<br />
State of New-York, pp. 281-362, in a work entitled, " The Na-<br />
tural, Statistical and Civil History of the State of New-York, by<br />
James Macauley." 3 vols. 8vo. New- York, 1829.<br />
Engelhardt, (Ab. von,) Die Lagerstatte der Diamanten im Ural-<br />
Gebirge. 4to. Riga, 1830.<br />
Lancon, (H.,) L'Art du Lapidaire. Paris, 1830.<br />
Schulze, (H.,) Practisches Handbuch der Juwelierkunst und Edelsteinkunde.<br />
Quedlinburg und Leipzig, 1830.<br />
Vettermann, (A.,) Kurze Abhandlung iiber einige der vorziiglichsten<br />
. Classen der Buntsn oder Gefarbten Edelsteine. 8vo. Dresden,<br />
1830.<br />
Beudant, (F. S.,) Trait6 elementaire de Mineralogie.<br />
2d edit, in 2 vols. 8vo. 1830.<br />
8vo. Plates.<br />
Paris, 1834 ;<br />
Naumann, (C. Fr.,) Grundriss der Kystallographie. 8vo. Leipzig,<br />
1826 ; 2d edit. 2 vols. 1830.<br />
Glocker, (Dr.,) Handbuch der Mineralogie. 2 vols. 8vo. pi. Nurn-<br />
berg, 1831.<br />
Kobell, (Frantz von,) Charakteristik der Mineralien. Nurriberg,.<br />
1831.<br />
Heseell, Crystallometrie. Leipzig, 1831.<br />
Kupffer, Handbuch der rechnenden Kristallonomie. 4to. pi. St.<br />
Petersburg, 1831.<br />
Karsten, (Dr. C. J. B.,) System der Mineralogie geschichtlich statis-<br />
tisch, theoretisch und technisch. 5 vols. 8vo. and royal folio atlas,<br />
containing 51 plates. Berlin, 1831.<br />
Baldwin, (Ebenezer,) Annals of Yale College, in New-Haven, Con-<br />
necticut. 8vo. New-Haven, 1831. Contains a sketch of the Ge-<br />
ology and Mineralogy of the vicinity of Yale College.
APPENDIX. 487<br />
Proposals of the Phenix Mining Company, with a statement of the<br />
History and Character of their Mines in Granby, Conn. 30 pp.<br />
8vo. New-York, 1831.<br />
Abich, (H.,) De Spinello, dissert, inaug. chem. 8vo. Berolini,<br />
1831.<br />
sur les Diamans de 1'Oural.<br />
Parrot^Notices 9<br />
4to. Mem. de I'Acad.<br />
Imp. St. Petersburg, 1832.<br />
Walchner, Handbuch der gesammte Mineralogie. 1104 pp. 8vo.<br />
Carlsruhe, 1832.<br />
Emmons, (Ebenezer,) Manual of Mineralogy and Geology. 230 pp.<br />
12mo. Albany, 1826 ; 2d edit. 299 pp. 12mo. Albany, 1832.<br />
Jackson, (C. T.,) and Francis Alger, Remarks on the Mineralogy of<br />
Nova Scotia. 1 pi. 115 pp. 8vo. Cambridge, Mass., 1832.<br />
Del Rio, (C. Andres,) Elementos de Oryctognosia. '<br />
8vo. Philadel-<br />
phia, 1832.<br />
Mohs, (Friederich,) Der Naturgeschichte des Mineralreichs. Wien,<br />
1832.<br />
Brard, (C. P.,) .Description historique de sa collection de Mineralogie<br />
appliquee aux arts. 8vo. Paris, 1833.<br />
Kobell, (Frantz von,) Tafeln zur Bestimmung der Mineralien, etc.<br />
4to. Munich, 1833.<br />
Presl, (M. K. B.,) Anleitung zum Selbststudium der Oryctognosie.<br />
8vo. Prague, 1833.<br />
Catullo, Element! de Mineralogia applicata alia medicina e alia farmacia.<br />
2 vols. 8vo. Padua, 1833.<br />
Rose, (M. Gustav,) Elemente der Krystallographie. 8vo. 10 pi.<br />
Berlin, 1833.<br />
Uhde, Versuch einer genetischen Entwickelung, &c. A Philoso-<br />
phical Essay on the Mechanical Laws of Crystallization.<br />
Breme, 1833.<br />
8vo. 4 pi.<br />
Prestel, (A. E.,) Anleitung zur perspective Entwerfung, &c. On the<br />
Perspective projection of Crystalline forms. 8vo. pi. Gottingen,<br />
1833.<br />
Welsh, (Jane Kilby,) Familiar Lessons in Mineralogy and Geology,<br />
designed for the use of young persons and Lyceums. 2 vols.<br />
12mo. Boston, 1833.<br />
Hitchcock, (Edward,) Report on the Geology, Mineralogy, Botany<br />
and Zoology of Massachusetts, made and published by order of<br />
that State. 700 pp. 8vo. Amherst, 1833.<br />
Cairne, (A.,) La Science des Pierres precieuses appliquee aux arts.<br />
Paris, 1833.
488 APPENDIX.<br />
Blum, (Dr. Reinliart,) Die Schmuckstejne. Heidelberg, 1828, und<br />
Taschenbuch der Edelsteinkunde. 12mo. Stutgart, 1834.<br />
Burch, (A.,) Handbuch fiir Juweliere. Weimar, 1834.<br />
Ilartmann, (C. F. A.,) Mineralogie. 8vo. pi. llmenau, 1828 ; also<br />
in 1834. 9<br />
Hartmann, (C. F. A.,) Repertorium der Mineralogie. 8vo. pi, Leipzig,<br />
1834.<br />
Allan, (Robert,) A Manual of Mineralogy. 350 pp. 8vo. Edinburgh,<br />
1834.<br />
Suckow, (M. G.,) Grundriss der Mineralogie. 8vo. Darmstadt, 1834.<br />
Mather, (William W.,) Sketch of the Geology and Mineralogy of<br />
New-London and Windham Counties, in Connecticut. 36 pp % 8vo.<br />
with a map. Norwich, 1834.<br />
Moore, (N. F.,) Ancient Mineralogy, or an Inquiry respecting Mineral<br />
Substances mentioned by the Ancients. 192 pp. 12mo. New-<br />
York, 1834.<br />
Porter, (Jacob,) Topographical Description and Historical Sketch of<br />
Plainfield, in Massachusetts. 44 pp. 8vo. Greenfield, 1834.<br />
Hartmann, (C. F. A.,) Grundziige der Mineralogie und Geologic.<br />
8vo. Nwrnberg, 1835.<br />
Richard, (A.,) Precis elementaire de Mineralogie. 8vo. pi. Paris,<br />
1835.<br />
Frankenheim, (M. .L.,) Die Lehre von der Cohasion, umfassend die<br />
Elasticitat der Gase, die Elasticitat und Coharenz der flussigeii<br />
und sesten Korper und die Krystallkunde. 502 pp. 8vo. Breslau,<br />
1835.<br />
Necker, Le regne mineral ramene aux methodes de 1'histoire<br />
naturelle. 2 vols. in 8vo. of above 400 pages each. Paris, 1835.<br />
Thomson, (Thomas,) Geology and Mineralogy, forming the third<br />
portion, or the fourth and fifth volumes of his System of Chemistry.<br />
2 vols. 8vo. London, 1835.<br />
Shepard, (Charles Upham,) Treatise on Mineralogy, 1st part one vol.<br />
12mo. New-Haven, 1832. 2d part consisting of descriptions of the<br />
species, and tables illustrative of their Natural and Chemical<br />
affinities. 2 vols. 12mo. with^SOO wood cuts. New-Haven, 1835.<br />
Kurr, Grundziige der okonom-techischen Mineralogie. 8vo. 1836.<br />
Hochsteller, Populare Mineralogie. 12 pi. 8vo. 1836.<br />
*Moffatt, (J. M.,) Mineralogy and Crystallography ; pp. 236-298 of<br />
the Scientific Class Book. Reprinted with additions from, the<br />
London edition, by Walter R. Johnson. 12mo. Phttadel/phia,<br />
1836.
APPENDIX. 489<br />
Gesner, (Abraham,) Remarks on the Geology and Mineralogy of<br />
Nova Scotia. 8vo. 272 pp. Halifax, 1837.<br />
Dowd, (J. A.,) System of Mineralogy. New-Haven, 1837.<br />
Feuchtwanger, (Lewis,) Treatise on Gems. New-York, 1838.<br />
Hertz, (B.,) Catalogue of Mr. Hope's Collection of Pearls and Precious<br />
Stones, systematically" arranged and described. 4to. London,<br />
1839.<br />
Rose, (G.,) De Novis quibusdam Fossilibus quae in montibus Uraliis<br />
inveniuntur, Chrysoberillum, Uralium, etc. 8vo. Berobini, 1839.<br />
Blum, (J. R.,) Lithurgik, oder Mineralien und Felsarten, nach ihrer<br />
Anwendung in Oekon., Artist, und Technischer Hinsicht systematisch<br />
abgehandelt. Stutgart, 1840.<br />
Roy, (C. W. van,) Ansichten iiber Entstehung und Vorkommen des<br />
Bernsteins, so wie praktische Mittheilungen iiber den Werth und<br />
die Behandlung desselben als Handelsware. 8vo. Dantzig, 1840.<br />
Konneritz, (L. von,) Mittheilung mannichfaltiger Versuche Edel-<br />
steine kunstgemass zu schleifen. Weimar, 1841.<br />
Steinbeck, Ueber die Bernstein-Gewinnung. 8vo. Brandenburg,<br />
1841.<br />
Petzholdt, (M.,) Beitrage zur Naturgeschichte des Diamantes. 8vo.<br />
-<br />
Dresden und Leipzig, 1843.<br />
Transactions of the Imperial Russian Mineralogical Society at St.<br />
Petersburg, 1842.<br />
Ramdedsberg, (C. F.,) Chemical Mineralogy. Berlin, 1843.<br />
Alger, (Francis,) Elementary Treatise on Mineralogy, by William<br />
Phillips. Boston, 1844.<br />
Bielhe, (Von,) Bernstein, ein gewichtiges Naturproduct des Konigreichs<br />
Danemark. 8vo. Hamburg, 1845.<br />
Haidinger, (W.,) Ueber den Pleochroismus dee Amethysts. Natur-<br />
mssenschaftliche Abhandlungen. Wien, 1846.<br />
Priifer, (V.,) Ueber die Krytalfonn der Lazulith. 4to. Naturwissensch.<br />
Abhand. Wien, 1847.<br />
Goepert, (H. R.,) Ueber Pflanzenahnliche Einschlusse in den Chalcedonen.<br />
8vo. 1848.<br />
Haidinger, (W.,) Ueber den Pleochroismus des Chrysoberylls.<br />
Berichte iiber Mittheilungen von Freunden der Naturwissenschaf-<br />
ten. 8vo. Wien, 1848.<br />
Haidinger, (W.,) Ueber eine neue Varietat von Amethyst. Derik-<br />
8chHfLd.Kais.Akad. 4tov Wien, 1849.
490 APPENDIX.<br />
*<br />
Harting, (P.,) Description d'un Diamant remarquable, contenant'des<br />
crystaux. Acad. roy. des Sciences. 4to. Amsterdam, 1850.<br />
Loew, Ueber den Bernstein und die Bernstein-Fauna. Berlin,<br />
1850.<br />
Zerrenner, (Dr. Carl,) De Adamanti Dissertatio. Lipsice, 1850.<br />
Zerrenner, (C.,) Anleitung zum Diamanten. Wasclien aus Seifenge-<br />
birge, Ufer-und Flusbett-Sand. 8vo. Leipzig, 1851.<br />
Hindmarsli, (R.,) Precious Stones, being an account of the Stones<br />
mentioned in the Sacred Scriptures. 8vo. London, 1851.<br />
Booth, Encyclopedia. Philadelphia, 1852.<br />
Rose, (G.,) Das Krystallo-Chemische Mineral-system. 8vo. Leipzig,<br />
1852.<br />
Haidinger, (W.,) Pleochroismus und Krystallstructur des Amethystes.<br />
Sitzungsber. der Kais. Akad. 8vo. Wien, 1854.<br />
Fontenelle, Nouveau Manuel Complet du Bijoutier. 8vo. Paris,<br />
1855.<br />
Labarte, (M. Jules,) Handbook of the Arts of the Middle Ages and<br />
Renaissance as applied to the Decoration of Jewels, Arms, etc.<br />
8vo. London, 1855.<br />
Schmidt, (C. J.,) Das Wichtigste iiber den Opal in Allgemeinen und<br />
iiber sein Vorkommen in Mahftsn im Besonderen. Mittheil. d. k.<br />
k. mdhr. scJiles. Gesellsch. Brunn, 1855.<br />
Volger, (G. H. O.,) Versuch einer Monographic des Borazites.<br />
ver, 1855.<br />
Hano-<br />
Volger, (G. H. 0.,) Epidot und Granat, Beobachtungen iiber das<br />
gegenseitige Verhiiltniss dieser Krystalle. 4to. Zurich, 1855.<br />
Kokscharow, (Nic. von,) Ueber die russischen Topase. 4to. Mem.<br />
de I'Acad. Imp. Petersbourg, 1856.<br />
Krause, (T. H.,) Pyrgoteles, oder die edeln Steine der Alten in<br />
Bereiche der Natur, etc. Halle, 1856.<br />
Loninser, (Gust.,) Die Marmaroscher Diamanten. 4to. Presburg,<br />
1856.<br />
Ritter, (C.,) Der Tu-(Yu-)stein, d. i. der Tu-chi der Chinesen, Kasch<br />
der Tiirken, Yeschet der Perser, oder Jaspis der Alten, sein Fun-<br />
dort in Khotan, sein Verbrauch und Handel. 8vo. Berlin, 1856.<br />
Ginanni, (Fantuzzi M.,) Osservazioni geognostiche sul Coloramento<br />
di alcune Pietre e sulla formazione di un Agata nel Museo Ginanni<br />
di Ravenna. 8vo. 1857.<br />
Mobius, (K.,) Die echten Perlen. 4to. Hamburg, 1857.<br />
Barbot, (Ch.,) Traite complet des Pierres precieuses. 8vo. Paris,<br />
1858.
APPENDED<br />
491<br />
V<br />
Haidinger, (W.,) Der fiir Diamant oder noch Werthvolleree aus-<br />
gegebene Topas des Herrn Dupoisat. Sitzungsber. der Kais. Akad.<br />
4to. Wien, 1858.<br />
Rudolph, (A.,) Die edeln Metalle und Schmucksteine, mit 37 TabeUen.<br />
Breslau, 1858. "<br />
Scheerer, (Th.,) Ueber den Traversellit und seine Begleiter Pyrgom,<br />
Epidot, Granat. Ein neuer Beitrag zur Beantwortung der Plutonischen<br />
Frage. Bericht. der Kngl. sdcJis. GeseUsch. 8vo. Leipzig,<br />
1858.<br />
Feuchtwanger, (Dr. L.,) A Popular Treatise on Gems, in reference<br />
to their scientific value, etc. 8vo. New-York, 1859.<br />
Hessh'ug, (Th. von,) Die Perlmuschel und ihre Perlen. 8vo. Leipzig,<br />
1859.<br />
Kluge, Edelsteinkunde. Leipzig, 1860.<br />
Pole, (W.,) Diamonds. 8vo. Land. Archaol. Trans. London, 1861.<br />
Pisani, (J.,) Sur le Grenat octoedrique de 1'Ile d'Elbe. 4to. Comptes<br />
rend, de VAcad. des Sciences. Paris, 1862.<br />
Sotto, (Js.,) Le Lapidaire du quatorzieme Siecle. 8vo. Wien, 1862.<br />
Zepharovitch, (V. v.,) Der Diamant, ein Popularer Vortrag. 8vo.<br />
Gratz, 1862.<br />
Lacaze, (Duthiers H.,) Histoire Naturelle du Corail, Organisation,<br />
Reproduction, Peche en Algerie, Industrie, etc. 8vo. Paris, 1864.<br />
Von Kobell, (Franz,) Die Mineralogie. Leipzig, 1864.<br />
Madelung, (A.,) Die Metamorphosen von Basalt und Chrysolith von<br />
Hotzendorf in Mahren. 4to. * Jahrb. d. Geol. Reichsanst. Wien,<br />
1864.<br />
Partsch, (P.,) Catalogue of the Geological Cabinet at Vienna, with<br />
a Biographical List of the Works treating on the subjects of Ge-<br />
ology, Oryctology, and Palaeontology. 8vo. Vienna, 1864.<br />
Emanuel, (H.,) Diamonds and Precious Stones. London, 1865.<br />
Annales des Mines. Paris.<br />
Boetius, (Anselmus,) Tractatus de Lapidibus et Gemmis. Var. ed.<br />
Bondary, (Jean de la Taille de,) Blason des Pierres precieuses.<br />
Bouillon, (De la Grange,) Analysis of the Substance known by the<br />
name of Turquoise. Nick. Journ. xxi. 182.<br />
Cardanus, (Hieronymus,) De Lapidibus preciosis ; also de Subtilitate.<br />
Var. ed.<br />
Guyton-Morveau, (B. L.,) Account of certain Experiments and Inferences<br />
respecting the combustion of the Diamond and the Nature<br />
of its composition. Nich. Journ. iii. 298.<br />
Kohler, (H. K. A. von,) Kleine Abhandlungen zur Gemmenkunde.
.<br />
492 .APPENDIX.<br />
Lucretius, De Rerum Natura. Var. ed.<br />
Mortimer, (Cromwell, M. D.,) Remarks on the Precious Stone called<br />
Turquois. Phil. Trans. Abr. viii. 324. London.<br />
Phillips, Mineralogy. Var. ed.<br />
Philostratus, De Vita Apollonii. Var. ed.<br />
Vauquelin, (Citizen,) Information respecting the earth of the Beryl.<br />
Mch.Journ.u. 393.<br />
Vauquelin, (Citizen,) Analysis of the Chrysolite of the Jewellers,<br />
proving it to be Phosphate of Lime. Nich. Journ. ii. 414.<br />
Vauquelin, (Citizen,) Analysis of the Aqua Marine or Beryl, etc.<br />
Nidi. Journ. ii. 358.<br />
Vega, (Garcilaso de la,) History of the Incas. Var. ed.<br />
Wecker, or Weckerus, Antidotae speciales de Lapidibus minus pretiosis<br />
alterantibus.<br />
Poggendorff's Annalen der Physik und Chemie.<br />
Brooks in the Encyclopedia Metropolitain.<br />
Berzelius' Annual Reports.<br />
London, Edinburgh and Dublin Philosophical Magazine.<br />
Jamieson's New Edinburgh Journal of Science.<br />
Brewster's Edinburgh Journal of Science.<br />
Thomson's Records of General Science.<br />
Reports of the British Association.<br />
De Ik Beche's Report.<br />
Silliman's American Journal of Science.<br />
Haiiy, (L. Abbe,) Tableau comparatif des resultas de la Crestallo-<br />
graphie et de 1'analyse chimique, relativement a la classification<br />
des mineraux. 8vo. Figs. Paris.<br />
Kidd, (J.,) Outlines of Minerology. 2 vols. 8vo. Oxford.<br />
Karsten's Archiv fur Mineralogie. 8vo. Berlin.<br />
Glocker, Mineralogischen Jahreshefte. 8vo. Breslau.<br />
Hartmann, Jahrbuch der Mineralogie, Geologie, &c. 8vo.<br />
Leonhard und Bronn, Neues Jahrbuch fur Mineralogie, Geographie,<br />
Geologie und Petrefaktenkunde. 8vo.<br />
The British Museum, containing some Ancient Manuscripts relating<br />
to the subject :<br />
Galamazar, Liber vertutibus Lapidum Pretiosorum quern scripsit<br />
Galamazar, Thesaurarius Regis Babylonie, ipso presenti et pre-<br />
cipiente. Harleian MSS. 8vo.
APPENDIX. 493<br />
De Lapidibus, Avibus et Arboribus Indiae, Arabiae et AMcae. Har-<br />
leian M88. 8vo.<br />
Lapidum Pretiosorum usus Magicus, sive de Sigillis. Harleian<br />
MS8. 8vo.<br />
Liber Hermetis tractans de 15 Stellis et de 15 Lapidibus et de 15<br />
Herbis et de 15 Figuris. Harleian MSS. 8vo.
494<br />
TABLE OF THE DISTINGUISHING
495<br />
CHARACTERISTICS OF GEMS.
496<br />
TABLE OF THE DISTINGUISHING
49'<br />
CHARACTERISTICS OF GEMS. ( Continued.)
498<br />
TABLE OF THE DISTINGUISHING
499<br />
CHARACTERISTICS OF GEMS. ( Continued.)
502 APPENDIX.<br />
The value of stones above five carats is not attempted to be given,<br />
as it is impossible to fix it with any accuracy. It depends entirely<br />
on the demand for any particular size and the supply in the market ;<br />
it remains a matter of negotiation between the buyer and seller.<br />
When a Diamond has a very decided color, such as blue, red,<br />
green, &c., it is called a fancy stone, and will bring a most exorbitant<br />
price. A stone of five grains, of a brilliant emerald-green color, for<br />
which, if white, not more than 28 stg. could be obtained, has been<br />
known to sell for 320 stg. The terms first water, second water,<br />
&c., mean only first and second quality. Diamonds, when perfect,<br />
should be clear as a drop of the purest water, and they are described<br />
as second or third water when more or less clear, until decidedly yellow<br />
or brown, when they are termed colored. The value of stones of<br />
the first quality of a less weight than two grains, (half a carat,) is,<br />
according to Mr. Emanuel, 10 stg. per carat ; the second quality,<br />
8 stg. ; the third, 7 stg. per carat.<br />
The plates representing the sizes of the Diamonds, given in this<br />
Treatise, are drawn from nature ; still it is quite difficult to get at<br />
the actual weight, for the Diamond cutters of the present day turn<br />
their attention more to the production of the greatest weight from<br />
a given quantity of rough Diamond, than to the production of perfectly<br />
proportioned stones, for which reason we often meet with<br />
stones weighing three carats, whose proper weight, if reasonably<br />
spread, should be two, which renders them less valuable and not<br />
nearly so brilliant as one of two carats properly cut ; any<br />
over or<br />
under weight only detracts from its beauty. A well proportioned<br />
spread Diamond finds more amateurs than a heavy one. At present<br />
the following prices may be quoted for Diamonds in gold currency,<br />
*2 grains, (half a carat,) from ......... $68 to $75, gold.<br />
* 4 grains are equal to 1 carat.<br />
151)6 carats<br />
" "1 ounce troy weight.
APPENDIX.<br />
503<br />
Mr. Emanuel's price list quotes for 1865, in pounds sterling and<br />
shillings :<br />
A Brilliant, weighing i of a carat, stg.<br />
" " "<br />
f<br />
" "<br />
"<br />
1 "...."<br />
5 10*. 5d.<br />
9 10<br />
18<br />
" "<br />
li<br />
" " "<br />
28<br />
ft<br />
-Jl<br />
(( ft<br />
gg<br />
**<<br />
' ~ \<br />
"<br />
-'.<br />
If<br />
2<br />
"<br />
"<br />
" "<br />
"<br />
48<br />
65<br />
^-: w-<br />
*"'''-"' "<br />
2i<br />
2<br />
V-.--< ..,"/' 2f<br />
> 3<br />
3i<br />
3i<br />
3f<br />
'.'"*'. 4 "".;>;<br />
4J<br />
4i<br />
4|<br />
5<br />
:<br />
-*<br />
\- ".,':..;*;'<br />
"<br />
"<br />
" "<br />
"...."<br />
70<br />
88<br />
100<br />
" "...." 125<br />
" "<br />
.... 135<br />
"<br />
"<br />
"<br />
"<br />
...'.<br />
"...."<br />
* w<br />
150<br />
175<br />
220<br />
" " "<br />
230<br />
"<br />
"<br />
" "<br />
"...."<br />
250<br />
280<br />
" "...." 320<br />
The Rose Diamond, which is not much in use in Europe, but more<br />
in South America, has not a very fixed value. The small Rose Dia-<br />
monds, if under 40 to the carat, are worth about five shillings each ;<br />
above that size, and up to one carat, bring from 9 stg. to 11 stg.<br />
the carat.<br />
Ruby and Emerald. Both these gems, when really fine, free from<br />
any defect, in color or size, are worth as much as Diamonds of the<br />
same weight. ^<br />
A fair Ruby is worth from $30 to $40 per carat. A fine and pure<br />
Ruby, well spread and proportioned, is worth, according to Mr.<br />
Emanuel<br />
Of 1 carat, stg. 14 to 20<br />
" "<br />
H 25 to 35<br />
2<br />
" "<br />
70 to 80<br />
"<br />
3<br />
"<br />
200 to 250<br />
4<br />
" "<br />
400to450<br />
And those below the weight of one carat range from 2 to 8 stg.<br />
while stones of greater weight than four carats are of<br />
per carat ;
504 APPENDIX.<br />
Bucli exceptional occurrence as to command fancy prices. Again, a<br />
Ruby of four carats, but of a pale color, may not be worth 12 stg.<br />
The Emerald is so rarely found perfect that the saying, "An<br />
Emerald without a flaw," has passed into a proverb. A good Em-<br />
erald is at the present day worth more than a Ruby, on account of<br />
the pleasing effect it has both by day and candle-light, and is a very<br />
favorite gem ; stands high in value ; but the Emeralds found lat-<br />
terly and brought into market are far inferior to those formerly<br />
found. A good Emerald is worth in this country $40 to $50 per<br />
carat. In England the price ranges from 5s. to 15 stg. per carat ;<br />
but one of deep, rich grass-green color, clear and free from flaws,<br />
may bring from 20 to 40 stg. per carat.<br />
Sapphire. A fine, perfect, evenly colored spread Sapphire, weighing<br />
one carat, of a deep rich blue color, by night as well as by day,<br />
is worth 20 stg. ; it does not, however, increase so much in isalue<br />
in proportion to its size.<br />
The Spinel or Balajs-Ruby, if of good quality, is sold from 10s. to<br />
8 stg. per carat. The value is extremely uncertain and variable ;<br />
it depends entirely on caprice and fashion.<br />
The Topaz. The commercial nature of the Topaz as a jewel is<br />
entirely fictitious. A very fine stone can now be bought for a few<br />
shillings sterling, whilq it would have brought a great deal more<br />
when in fashion. Pink Topaz brings from 2 stg. to 20 stg. per<br />
ounce, the price depending on the depth of the pink color.<br />
Beryl or Aquamarine. The commercial value of this stone is<br />
trifling, and is used mostly for imitation jewelry. Zircon, Hyacinth<br />
or Jacinth, are also called Jargoon. These stones, are identically the<br />
same, but differ in color ; the red varieties are sometimes sold for<br />
inferior Rubies. The Jargoon is frequently cut in the form of a Rose<br />
Diamond, which is flat at the bottom and pointed at the top. The<br />
price is purely%rbitrary.<br />
The Garnet, Essonite, Pyrope and Almandine. The color of the<br />
Syrian Garnet, being of deep crimson, is at present much in vogue,<br />
and commands a fair price, say from $1 to $2 per carat.<br />
The Bohemian Garnets are worth from $15 to $25 per ounce.<br />
Amethyst. A fine deep-colored stone, of the size of a twenty-five<br />
cent piece, is worth from $80 to $100 per ounce ; smaller sizes and<br />
inferior qualities are sold for 50 cents to $10 apiece.<br />
Peridote, Chrysolite. The value of both stones is but small ; fair<br />
specimens of good size may be bought at from 25c. to $5 per carat.<br />
Turquoise. The Persian is much used in jewelry ; small, clear
APPENDIX. 505<br />
stones bring from sixpence to 20*. stg. each, while a fine Ring<br />
stone will realize from 10 stg. to 40 stg. Large Turquoise, of<br />
good quality and fine color, are extremely rare, and realize extravagant<br />
prices.<br />
Opal. The value of the precious Opal depends entirely on the<br />
brilliancy and play of its colors ; large, fine gems, of extraordinary<br />
beauty, have brought fabulous prices. They are not sold by the<br />
carat, but by the piece.<br />
Coral. The red Coral, which formerly was the most valuable, is<br />
now worth far less than the color which was formerly worthless.<br />
The pale, delicate pink, similar to that of the inside of the pale rose<br />
leaf, is sought after, but very scarce ; a Coral of this tint is very<br />
valuable. 48 stg. per ounce has lately been paid in London. A<br />
large bead or drop will readily realize from 30 stg. to 40 stg. ;<br />
small pieces, however, may be had for $4 to $6 per ounce.<br />
Pearls. The value for perfectly pure round Pearls, of a smooth<br />
and lustrous skin, perfectly free from specks or discoloration of any<br />
sort, of small size, is from 4 grain Pearls,<br />
6<br />
" "<br />
$1 to<br />
2 to<br />
5 to<br />
$2 a grain.<br />
"<br />
3<br />
6<br />
10<br />
" "<br />
8 to 10<br />
The following is Mr. Emanuel's table of prices of Pearls, viz. :<br />
A Pearl of 1 grain is worth from<br />
"<br />
2<br />
" " "<br />
2*. to<br />
6s. Qd. to<br />
2*. Qd.<br />
7. Qd.<br />
3<br />
" " "<br />
12*. to 16*.<br />
4<br />
" " "<br />
22*. to 28*.<br />
5<br />
" " "<br />
35*. to 48*.<br />
6<br />
" " "<br />
55*. to 65*.<br />
8<br />
" " "<br />
90*. to 110*.<br />
"<br />
10<br />
12<br />
"<br />
"<br />
"<br />
"<br />
"<br />
"<br />
8 stg. to<br />
12<br />
9 stg.<br />
"<br />
to 15 "<br />
"<br />
14<br />
" "<br />
15 "<br />
to 18 "<br />
16<br />
" " "<br />
20 "<br />
to 30 "<br />
18<br />
" " "<br />
30 "<br />
to 40 "<br />
20<br />
" " "<br />
40 "<br />
to 50 "<br />
24<br />
" "<br />
60 "<br />
to 70 "<br />
30<br />
" " "<br />
80 "<br />
to 100 "<br />
Round Pearls above the latter weight are of such rare occurrence<br />
and command such exceptional prices, that it would be useless to<br />
attempt any scale of valuation.
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LD 21-100m-6,'56<br />
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University of California<br />
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YB ,'5203