is
still sometimes called Sard. Except in the matter of colour, it has the
same properties as Chalcedony, and it occurs either as an ordinary
Agate, or in fissures as Vein Agate. Although of wide distribution, the
chief localities are only two. In India it is found in the Eajpipla
hills on the river Nerbudda; also on the Mahi river, north of Baroda.
When found in situ, the colour is usually very dark, sometimes
almost black, sometimes greenish, but on heating it assumes its well
known red colour; it is considered that a better colour results by
exposing to the rays of the sun, the process requiring as long as two
years. It is cut at Cambay.
In
Brazil it is found at Campo de Maia, associated with Agate. Arabia, New
Zealand, Scotland, Saxony and many other parts, also yield this
variety. Pliny mentions amine of Sard at Babylon.
The
modern name Carnelian was given to it on account of its flesh-colour.
Inferior coloured specimens may be improved by soaking in a solution of
an iron salt and then heating to produce the ferric oxide. It is rather
curious that this variety containing iron should have been held to be
specially efficaceous in the healing of wounds inflicted by iron
instruments. Epiphanius also mentions its value for the cure of tumours.
It
has always been a favourite substance in which to carve devices for use
as signets, and Pliny mentions the ease with which it left the wax then
used for sealing.
3. Chrysoprase is the variety coloured green by Nickel. It is not the same as the Chrysoprasius of Pliny, which was probably Peridot; the Chrysoprase we know seems to have been unknown to the ancients. It occurs in veins in a
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