GEMS AND PRECIOUS STONES OF GREAT BRITAIN. 
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defined colourless crystals near Falmouth and at Lundy Island 
in granite. In Scotland, both in Banffshire and Aberdeen, large 
and nearly transparent crystals are sometimes found, usually 
of a straw-yellow or apple-green colour, and also in greenish- 
yellow crystals from Eubislaw, near Aberdeen. 
Green beryl occurs somewhat abundantly in quartz veins 
traversing the granite, and also forming part of the granitic 
mass itself near Dungloe in Donegal, whence the specimen 
(fig. 3) was obtained. In fine blue crystals (fig. 9), from the 
Mourne Mountains, near Dublin, where it is associated with 
topaz, in which county, at Killiney and Dalkey, greenish 
crystals of some length have been discovered. The two specimens 
of aquamarine (fig. 8 dd)^ are from Scotland, where this 
variety occurs in the Cairngorm district. 
The Garnet is a silicate of alumina, lime, magnesia, iron, man- 
ganese, &c., in very varying proportions, nearly as hard as quartz, 
with a specific gravity between 3 and 4, crystallises in forms 
belonging to the cubical system, usually in dodecahedrons 
(figs. 6, 15), and occurs as imbedded crystals in granite, gneiss, 
metamorphic schists, and limestones. The colour of this mineral 
is extremely variable, being all shades of yellow, brown, red, 
black, and even green ; but the only ones used in jewellery are 
those of a light to deep red colour. The light ones are known 
under the name of Almandine, and the deep blood-red ones are 
the Carbuncle ; the former being usually facetted, whilst the 
latter are cut en cahochon, with the lower surface frequently 
hollowed out, when the colour is very intense, as in fig. 8/. 
Garnet is probably the most extensively distributed of the 
British representatives of precious stones, although rarely found 
in perfection in sufficient quantity to be rendered available, or 
to compete with the finer and purer specimens of this mineral 
obtained from other countries. Occasionally, however, it is 
found of sufficient purity and colour to be cut and polished, as 
at Elie Bay in Fifeshire, where transparent crystals (pyrope?), 
fit for purposes of jewellery, are collected along the shore, 
derived from the adjacent trappean rocks, and known as “Elie 
Eubies.” In many other parts of Scotland, and in the Shetlands, 
both the common and precious varieties are found. Garnet occurs 
in dolomite of a cinnamon colour, in Donegal, Ireland, and as 
brilliant red crystals near Dublin ; also in Cumberland, Corn- 
wall, Isle of Anglesea, &c. 
Olivine, a silicate of magnesia — when of transparent yellow or 
greenish colour is known as Chrysolite, and used as a gem — is 
common in many of the British basaltic rocks ; but we are not 
aware that it has been found in pieces sufficiently large and 
compact to admit of its being cut and polished. 
Tourmaline, a boro-silicate of alumina, iron, &c., has nearly 
