This was widely used to imitate diamond in the
United States in the 1940s and 1950s, but was soon ousted
by the appearance of more satisfactory imitations on the market.
Appearance It has very strong luster and
is always given a brilliant cut. Normally, it is slightly
cloudy rather than perfectly transparent. It has a faint yellowish
tinge, but because of its very high dispersion looks positively
iridescent in bright light. Under a lens, its very strong
birefringence produces an obvious doubling of the facets and
edges which is more striking, for instance, than that of zircons.
Because the stone is not very hard, the facet edges are not
sharp, and it feels slippery.
Distinctive features Strong birefringence,
combined with very high dispersion, low hardness, and a yellow
tinge make it easy to recognize.
Cost Higher than that of other diamond simulants
such as cubic zirconia or YAG, but lower than that of the
most costly synthetics, such as emerald.