A TABLE OF GEMS..

Continued from p. 105.

Class fifth.

LAPIS LAZULI..

SPECIFIC GRAVITY from 2,1, to 3,15.

Analysis.

Gypsum 20; Martial Fluor 80 *.

ICELAND ZEOLITE, Arg. 20; Sil. 50; Cal. 8; Water 22 f.

Form.

It is found in irregular mafses, seldom exceeding a few pounds, of a beautiful opaque blue, and generally sprinkled over with bright yellow or white pyritaceous specks or veins, vulgarly taken for gold

and silver.

Structure, Properties, &c.

Texture fine and granular, taking a good polish. It retains its colour most obstinately in a strong heat. In powder it effervesces slightly with acids; and calcined, it forms with them a gelatinous mafs, like the rest of the zeolite genus, in which Cronstadt and Born rank it; and the last author says it is coloured by iron. In a strong heat it melts into a whitish glass. It sometimes contains silver as far as one ounce in one hundred pounds.

Where found.

Found in Bucharia, China, in Rufsia, and the mountains which surround the south of the Baikal Sinus, and at the rivulet Sliudenka, by the intendant Laxman. Her imperial majesty has a room in her palace of Sarscocello entirely fitted up with it, the walls, tables, &c. being incrusted at an immense

expence

Value.

From eight to twenty rubles per pound.

Clafs sixth.

MALACHITE, AND ARMENIAN STONE.

Varieties.

MALACHITE, green of different fhades, sometimes with beautiful black dentroides.

ARMENIAN STONE, blue.

Analysis

MALACHITE, Copper 75 ; Aer. Acid 25

Form.

The fine Siberian green malachite, on account of its beauty and rarity, has often been ranked with precious stones of the second order, although an ore of copper the richest that exists. It is found in mafses of a stalactical appearance, composed generally of a number of globular parts, like pebbles cemented together with the same green matter, so that when cut in a certain direction, it has the appearance of a beautiful green pudding stone, so hard as to take a fine polish.

*Pallas.

Where found.

It is only in the Ghoumecheffkoy mine, forty versts south of Catherinebourg in Siberia, that the fine hard kind is found, so much esteemed by lapidaries and collectors. This surpasses as much the Chinese, as that does the bastard malachite of Spain, Tyrol, and Hungary. Here are found likewise the fine sattin and velvet malachites, in such high estimation, though not hard enough for trinkets. The value of the fine malachite is very great; the author sold a plate of it twenty-six inches long, by sixteen large, and two thick, to count Stragonoff, a Russian nobleman, and a large proprietor of Siberian mines, for two thousand rubles. An account of that specimen is given by Pallas in the tenth volume of the Medical Commentaries of Edinburgh. Her imperial highness, the grand duchefs of Rufsia, has a table incrusted with the velvet malachite, and prince Potemkin had a plate of it of still greater value than the one possessed by the author. Besides these two extraordinary specimens, the imperial Academy of Sciences, and some of the Rufsian nobility, have large specimens in their collections, although all inferior to them, as is that in the emprefs's cabi

net.

a

The Armenian stone is merely a blue malachite.
Value.

From ten to two thousand rubles for a specimen, according to size and quality.

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CATALOGUE OF GEMS ARRANGED TO THEIR DEGREE OF HARDNESS, AS FAR AS YET KNOWN, ACCORDING TO MR QUIST'S PLAN, IN WHICH EVERY STONE SCRATCHES THOSE THAT ARE OF A NUM

BER LOWER THAN THAT WHICH IS ANNEXED TO ITSELF.

CATALOGUE OE GEMS ARRANGED ACCORDING TO THEIR SPECIFIC GRAVITY AS FAR AS YET KNOWN,

INDEX OF GEMS OF THE FIRST AND SECOND ORDERS.
The following abbreviations are here used. O denotes Order,→
C. Clafs, V. Volume,-and P,

Page.