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GEMS.
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torrents.
The Hindoos increase their brilliancy by subjecting them to the action
of heat. The price of this substance in a rough state varies from six
to ten " lire " the kilogramme.
The Western carnelian is less hard, of a clear yellowish red, and not very brilliant.
One
variety, called panacea, or stigmite, is of a pale yellow red, striped
white, with red or black curved lines ; sometimes this kind is pale,
whitish, and as if spotted with blood.
The tree carnelian has marks of ramification of a bright red colour on a very white ground.
Certain
chemical agents act on this stone with the assistance of heat. When a
fine carnelian is covered with carbonate of soda, and afterwards
exposed to a certain heat, a silicate, hard as the stone itself, forms
on the surface ; whenever then, over this silicate which covers the
carnelian, a design is made with a ferruginous cement, the silicate
loses its colour at the points of contact and reappears in that of the
carnelian. By this means, therefore, very ingenious designs can be made
on the stone in question.
The
ancients made no distinction between the sardonyx and the carnelian,
which are often found inside one another; the sardonyx being more dense
in the centre ; the carnelian at the outside.
We
must not silently pass over the fact that the carnelian, since the
remotest period, has been used not only as an ornament but has also
been cut and engraved in a thousand ways. This may be attributed to the
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