30 DIAMOND CUTTING
the
rough diamond is fastened with cement to the end of a wooden holder and
a tiny groove is scratched with another diamond on the stone at the
point where it is to be cleaved. The stone is then held by the clamp in
correct position, and then a heavy steel blade is placed on the
diamond, and this blade is struck a smart tap on the back and the stone
divides along the line previously determined. The operation seems very
simple, but is one that requires excellent knowledge of the stones as
well as experience.
Sawing
has been used some twenty years or more, and enables the cutter to
divide the stone along any plane, independent of its structure, while a
diamond can be cleaved only along its natural cleavage lines. The
diamond saw is about three and one half inches in diameter, and
consists of a very thin piece of a special alloy, the edge of which is
treated with diamond dust. The work is done very slowly, several hours
being required to cut one diamond, so that one workman operates a large
number of saws at the same time.
After
being cleaved or sawed the stone is again examined by an expert, and a
plan for further work on that particular stone is determined on. The
most important point in this is
