126 
POPULAR SCIENCE REVIEW. 
Amorplious 
Silicates . 
Boro-silicates 
Fluo-silicates 
Aluminates 
Fluorides . 
Sulphides . 
Carbonates 
Sulphates . 
Organic Minerals 
( Agate, Onyx, Sardonyx, Cornelian, Flint,. 
\ Jasper, Heliotrope, and Opal. 
'Kyanite, Bisthene or Sappare, lolite or the 
Sapphir d’eau, Zircon, Beryl, Aquamarine, 
Emerald, Felspar, Adularia, Green Felspar, 
Garnet, Almandine or noble Garnet, Olivine, 
Chrysolite, Serpentine (noble and common). 
Tourmaline, Eubellite, Schorl. 
Topaz. 
Sapphire, Spinel. 
Fluor Spar. 
Iron Pyrites. 
Malachite, Marbles. 
Alabaster and Satin Spar. 
Amber, Jet, Cannel Coal. 
Notwithstanding that all the minerals which are included 
in the above list (many of which are entitled to he considered 
as gems or precious stones), occur in Grreat Britain, still it is 
but rarely that specimens are encountered of sufficiently fine 
water or colour as to render them worthy of the labour of the 
lapidary. As proof, however, that such stones do occur, which, 
when cut and set, may present a very pleasing and ornamental 
appearance, we have in the accompanying plate figured an 
ornamental gold snuff-box, set with stones and pearls from 
Scotland, which was presented to the late distinguished geologist. 
Dr. Maculloch, by the Duke of Athol. This unique specimen 
may now be seen in the Jermyn Street Museum, where it forms 
part of that valuable and interesting collection.* 
Amongst the most familiar mineral substances is quartz, which 
in its transparent and colourless form is termed rock-crystal. 
It is usually found occurring in crystals which are six-sided 
prisms transversely striated, terminated by similar faced pyra- 
mids, as shown in fig. 7 from' Carlow, and fig. 5, PL XXIIL 
representing a crystal from the hematite mines of Cumberland, 
in which the lateral planes are scarcely visible. Its chemical 
composition is pure silica, and the specific gravity is 2*6. 
Crystals of quartz are found in all parts of the world, and in 
rocks of all ages, both as forming part of the rock mass itself, 
or occurring in veins, cavities, and geodes of such rocks. In the 
latter cases it attains its finest development, often in crystals of 
immense size, and occasionally highly transparent. Such large 
and colourless crystals were formerly highly prized, and by 
enormous patience and labour were worked into various orna- 
mental articles often estimated at fabulous prices. Although 
* By the courtesy of the Director of this Institution, we are enabled to 
figure this box, which is said to have originally cost 100 guineas. 
