18 PRECIOUS STONES
from
a purple spinel. A lustrous yellow zircon of fine color may bear a
puzzling resemblance to a canary diamond, yet there is a perceptible
difference, hard to explain, and it feels heavier in the handling.
The
difference between an Oriental and a quartz cat's-eye is unmistakable
after the first introduction: the texture of the Oriental appears
finer, the colors softer, the lustre harder.
The
green of the emerald is not approached by any other stone, though there
are some remarkable imitations made. The doublet imitations of this
stone are not good; the color is dark and murky.
No
red stone approaches the velvet of the ruby. There are, however, two
forms of manufactured ruby which are dangerous. The first of these to
appear was called the " reconstructed ruby." It can be distinguished
from the natural ruby by the confused bubbles which appear in the body
of the stone, as though it had congealed while boiling. Another and
later production, termed the " scientific ruby," is much more perfect.
The color is usually very beautiful, and many of the stones are quite
clear. Close observation, however, will discover a series of fine lines
in irregular waves, impossible to the natural grain of a crystal.
Tourmaline
and some of the fine green diopsides found in New York State may be
confounded, but as few of the latter come into the market, confusion is
not liable to occur.
The
distinction between ruby and sapphire is simply one of color. The red
stone is a ruby. As it pales, it finally reaches a point where it is
termed a pink sapphire, unless the color is free from a decided tinge
of blue, when it is called a pink, or Ceylon, ruby. Blue in various
shades is the ordinary sapphire; all other colors in corundum are
known as " fancy" sapphires.
Olivines
and green garnets have been so confounded that the latter have come to
be known commercially as olivines, and the olivine of mineralogy has
become peridot.
