of Vespasian, in the Marlborough collection. The Romani
employed green and bright vermilion jaspers for their worksj
but the Egyptians and the Gnostics preferred the yellow.]
They frequently selected the heliotrope or blood-stone fori
'i
talismans, but very rarely for engraving. Some good specimens of antiques occur on nicolo, including an Apollo, belonging to the Herz collection, and the head of Caracalla, to the
Blacas.
Sard. — Early engravers had a decided preference for the
sardius, and some of their best works appear on this stone.
The Greeks chose the yellow tints, the Romans the red, though
a variety called sardine, of a deep red color, was employed both
by the later Greeks and the early Romans, and also by the
artists of the fifteenth century as well as by modern engravers.
A fine specimen of engraving on this gem, representing a
Bacchante, occurs in the Blacas collection.
Carnelian. — The most ancient Egyptian and Etruscan
intagli are found on this variety of precious stone, but after
the conquests of Alexander, it was superseded by the oriental
sard. Its color, toughness, and capacity for polish, render it a
desirable material for engraving.
Clialcedony. —■ This variety of quartz has been sought for
engraving by artists of all times ; it was used by the nations of
antiquity for Babylonian cylinders and for Etruscan scarabei,
and has been also a favorite with mediaeval and modern
engravers. When of a yellowish tint, it was called opaline, a
substance distinct from opal, a species not found among antique gems. It is estimated that a large part of engraved chalcedonies, notwithstanding its frequent use by the ancients, are
modern counterfeits. Obsidian anaßini were substances used
by the Assyrians and Egyptians in their earliest attempts at
engraving.
