184 THE DIAMOND MINES OF SOUTH AFRICA
against
each other with a rubbing motion over a trough. Considerable leverage
is obtained for the rubbing by resting the holders against projectors
at the sides of the trough. The exposed face of the stones is coated
with diamond dust to advance the process. In this laborious way facets
may be ground, and the cutting may be completed by repeatedly refixing
the stones in the cement. Expert handling is necessary to keep the
diamonds from becoming overheated by the constant friction.
Polishing
The
third process is that of polishing. The method employed does not
differ materially from that adopted in cutting, described above ; but
as this is the finishing process, all irregularities in faceting must
be corrected and the practised eye of the artist must detect and remedy
every defect. Each line and angle must be made geometrically correct;
each facet and lozenge must be shaped to perfection. The colorless
stone must glisten pure as a dewdrop sparkling in the sun, producing
the colors of the prismatic spectrum ; the gem of red or blue or green
color must flash forth its hue with intense brilliancy.
Such
exact and delicate alignments are not the work of a day, though the
time required has been greatly shortened by modern methods. The
patience of weeks and even of months must be expended in perfecting
these tiny crystals. It is said that it was the work of two years to
cut the celebrated Pitt diamond, now among the French jewels, and the
lapidary received for his skill and labor the sum of £3500
or $17,500. The last cutting of the Koh-i-nur by Coster of Amsterdam in
thirty-eight days was unusually rapid. The ablest workmen in Holland
were engaged continuously on it and the wheel was driven by steam
power; yet it cost $40,000 to do the work and the diamond lost
eighty-four carats in weight.1
1 " Great Diamonds of the World," Streeter, 1882.
