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Demantoid
This is a pale to clear green variety of andradite
garne garded as being comparable in luster to diamond; h -
the name, attributed to i; in the latter half of the ninetecentury.
Appearance The color varies from a cold,
very : green (almost colorless with a green wash), to a mw.
strong green, not as a rule a very lively color and simii
certain shades of green in tourmaline, zircon, or olivir often
has good transparency and exceptional luster I sions in the
form of fine, curved fibers of asbestos are quent and characteristic.
These stones are usually :: round, mixed, and brilliant cuts;
more rarely, square or tangular, step cuts. They are normally
small. SpecimF - more than one carat are uncommon, and those
of se. carats are extremely rare. Due to weakening inclusiorfacets
and edges are easily damaged with use.
Distinctive features The greenish color combinec
. strong luster, single refraction, and possibly asbestos
inclusions, are quite characteristic. However, the phsproperties
have to be measured to distinguish it from c grossular, green
YAG, and occasionally from certain c zircons with weak birefringence.
Occurrence It is found mainly in the Soviet
Union Value Because of its attractive appearance, color ticularly
when a lively, mid-green), and exceptional I~. plus its rarity,
it is one of the most valuable seco% gems
Simulants and synthetics Green YAG, an artificih
stance with the structure of garnet, is very similar an :
been used to imitate both demantoid and green grosFor the
time being, at any rate, synthetic demantoid produced.
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