THE BOOK OF DIAMONDS
this
amazing device but a single carat diamond can be cut in a day. Formerly
a diamond could be cut only by splitting it along its line of
cleavage; now the saw cuts its way through the stone at any angle. What
a diamond gains in brilliancy through being cut and polished, it loses
in size for about sixty per cent of the stone is cut and polished away
before it is ready for market.
The
apparatus consists of a small disk of spongy cast iron, turning on a
vertical spindle. The stone is imbedded in the apex of a metallic cone
and held by a clamp against the surface of the disk which is smeared
from time to time with a mixture of olive oil and diamond dust. This
apparatus requires constant attention as the stone may be permanently
damaged by over heating. The mistake of a single stroke in cleaving
the stone, may shatter it to pieces. Any diamond in the rough is full
of imperfections, with only certain parts clear and the skill comes in
saving as much of the stone as possible in providing it with some
fifty-eight faces. With a diamond-edged tool little slits are made in
the stone where the cutting is to take place, and just one of these
slits, misplaced, is likely to bring on a total ruin. Cutting diamonds
is an art so delicate and so precise that few outsiders ever learn it.
As
Europe did more to advance the art of cutting diamonds in a few
centuries than the Orient did in several thousand of years, so the
United States has done more in the last ten years than Europe did in
the centuries. Precious stones have been long sawed by the Chinese,
with a string charged with oil and emery, spun over a bow. It is said
that 82
