Imitation
amber made from gum copal can be detected by soaking in alcohol. The
joining of pieces of amber glued or melted together can be discovered
by the same method.
Imitation
pearls, under the glass, as compared with the genuine, lack body, are
iridescent, and show minute holes in the surface.
The eye cannot detect the yellow of off-color diamonds so clearly after looking at yellow stones.
White diamonds appear to have a brownish tint after one has looked at emeralds closely.
If
one turns immediately from yellowish-green stones (chrysolite, etc.) to
the examination of emeralds, the latter, even of the finest color, will
seem to have a bluish tint.
In judging the color of stones, do not pass the eye directly from one color to another.
