The Sard and Carnelion.
These
are two varieties of chalcedony, of bright red and yellow tints; the
liver-coloured or brownish-red specimens being called sard, and the
bright red, white, and yellow ones carnelions. The best stones of this
kind are found at Cambay and Surat, in India, and in Arabia; they are
also found in Saxony, Scotland, Ireland, and New Zealand. They take a
most beautiful polish, and are particularly adapted for seals, as they
"deliver" easily from the heated wax, without destroying the
impression. This quality was remarked by Pliny, who extolled the stone
beyond the sapphire. The name carnelion is derived from the Latin carnis, flesh,
on account of its colour. The carnelions are very little used in this
country, although popular in Germany and Poland. The specimens found in
Europe are generally of a muddy or cloudy tint, far inferior to those
coming from India. It is a fact that exposure to the sun for a
considerable period makes the colour of the stone brighter and deeper;
artificial heat fails to produce the same effect, which would lead to
the supposition that light as well as heat exercises an influence in
effecting the change in colour, which must arise from the oxidation of
the iron contained in the stone.
Chalcedony, Mocha-stones, Plasma, and Agate. Chalcedony is a variety of quartz; according to Fuchs,
