RUBY.
195
rubies, but the deceit is easily discovered by the differÂing hardness and the specific gravity.
We
do not know the name by which the ancients indicated the different
varieties of spinel ; only, in my opinion, it may be asserted that the
red or ruby spinel was described by Pliny under the name of alabandic
carbuncle, earhunewlus alabandieus, because, in speaking of
carbuncles in general, he affirms, " Alaban-dicos caeteris nigriores
esse;" that is, to' have a darker colour, and this is the case with the
spinel ruby. It is said to be procured in Ortosia, and cut in Alabanda.
whence the name given to them.
3. BALAIS RUBY.
By
balais is meant a ruby of a lighter colour than the spinel, rather
tending to pink, and whose specific gravity is never more than 3-446.
It is even less hard than the spinel ruby, and contains a greater
quantity of magnesia.
The
balais is more easily scratched by the emerald than the emerald is by
the rock-crystal. It will take a beautiful polish, but only as the
result of much patience, and the use of a special chemical composition
on the wheel when being worked. Caire is convinced that in India they
have, for this purpose, a secret specific, as balais are brought thence
scarcely out of the original form, yet having a beautiful artificial
light.
Neither balais nor spinels have ever been seen having the qualities of the asteria.
