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ADAMAS.
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tion
of the true Diamond into Greece, sharp fragments of Corundum obtained
from Naxos served the same purpose: the name Adamas was then doubtless
confined to the blue and grey Sapphires found in Cyprus, or to the
opaquer crystals of Corundum discovered in the emery-mines. Such a
stone reduced to sharp fragments would serve to cut into and excise the
Quartz gems, Sards, Agates, Jaspers, then in request as signets, with
almost as much facility as the Diamond itself. In fact, the amorphous
Corundum used from time immemorial by the Indian lapidaries for cutting
the hardest gems was known when introduced into the European atelier,
some ninety years ago, by the name of Adamantine Spar. That
some such mineral must then have represented the Adamas is a necessary
consequence of the established fact that works apparently executed
entirely by the Diamond-point and others with but little assistance
from the drill, belong for the most part to the archaic period of Greek
art, some ages before the true Diamond could have found its way thither
from India. Similarly within the last few years the Diamond-dust has
been superseded in Paris by the Carbonado, a black substance of the
same chemical nature, but found in Brazil much more abundantly, the
masses attaining to 1000 carats in weight. This, besides being employed
in powder, is fashioned, says Barbot, into a kind of graver (burin)
designed to act most efficaciously upon the hardest gems.
It
was not before 1475 that the art of cutting the Diamond into a regular
form so as to bring out all its lustre was invented by Louis de Berghem
(or Berquem), although Laborde1 has discovered mention of
the " tailleurs de Diamants," and one Herman designated a skilful
workman, established in Paris in 1407, and also three " diamant-slipers
" at Bruges in 1465. But the very designation of these last shows that
their profession extended no further than the polishing the stone, or
removing the greenish film that veils its transparency, and this might
be effected by emery-powder alone by a very tedious though effectual
process. L. de Berghem tried his newly-invented art upon three large
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