|
114
|
PRECIOUS STONES.
|
||
|
|
|||
|
that
of the diamond. At an auction of precious stones from the cabinet of M.
Dree a very beautiful diamond of 8 grains (2 carats) was sold for $148,
while a ruby of the same weight brought $186. At the same sale the
price of a ruby of 10 grains reached $2604. The value of the ruby and
that of precious stones generally varies with their richness of tone.
When
the corundum is perfectly colourless it possesses a brilliancy so vivid
that in some circumstances it may pass for a diamond. It may be
distinguished from the latter by its inferior hardness, its smaller
specific gravity (3-5, while that of the diamond is 3'9), and by having
double refraction.
According to the tints which the corundum possesses, it bears different names, and represents variable values.
Names of the corundums according to their colour:—
|
|||
|
|
|||
|
|
|||
|
|
|||
|
THE RUBY.
There exists but one true ruby, the oriental ruby.
|
|||
|
|
|||