cause of the difficulty that exists in distinguishing it from
the onyx agate, which it much resembles. It is much harder than
this stone, but the difficulty of determining the degree of
hardness without testing the stone prevents the possibility of
deciding whether a given substance be really calcedonyx, except
by the lapidary who tests it on Barbot is said to have
determined the, specific weight of this substance, which
according to him is 2-6180. It is often even more translucent
than agate. appears that it came from the East, and was not only
known to, but engraved by the ancients, and these engraved
stones are the only specimens in existence of the ealcedonyx,
as, at present, none is found in any part of the world that we
are aware of. the ancient collection of Genevosio, Caire saw an
engraved ealcedonyx, representing a warrior seated opposite a
dead body. In the Viennese cabinet of engraved gems there is
another, which represents a young man leaning on a column. this
name, of which every one understands