de is then inserted in the nick and a
sharp light blow struck upon the back of the knife blade. The diamond
then readily splits.

"CUTTING DIAMONDS." The next step is to give the rough material a shape
closely similar to that of the finished brilliant but rough and without
facets. This shaping or "cutting" as it is technically called, is done
by placing the rough stone in the end of a holder by means of a tough
cement and then rotating holder and stone in a lathe-like machine.
Another rough diamond (sometimes a piece of bort, unfit for cutting,
and sometimes a piece of material of good quality which it is necessary
to reduce in size or alter in shape) is cemented into another holder and
held against the surface of the rotating diamond. The holder is steadied
against a firm support. It now becomes a case of "diamond cut diamond,"
each stone wearing away the other and being worn away itself.

The cutting process is fairly rapid and it leaves the stone (which is
reversed to make the opposite side) round in form and with a rounding
top and cone-shaped back. Stones of fancy shape, such as square, or
cushion shape, have to be formed in part by hand rubbing or "bruting" as
it is called.

The facets must now be polished onto the stone. Usually the workers who
cut do not cleave or polish.

"POLISHING" DIAMONDS. The polisher fixes the cut stone firmly in a
metallic holder called a dop, which is cleverly designed to hold the
stone with much of one side of it exposed. The holder is then inverted
so that the stone is beneath and a stout copper wire attached to the
holder is then clamped firmly in a sort of movable vise. The latter is
then placed on the bench in such a position that the diamond rests upon
the surface of a rapidly revolving horizontal iron wheel or "lap" as it
is called. The surface of the latter is "charged" with diamond dust,
that is, diamond dust has been pushed into the metal surface which thus
acts as a support to the dust. The latter wears away the diamond,
producing a flat facet. The lap is kept moistened with oil and from time
to time fresh oil and diamond dust are applied. A speed of about 2,000
rotations per minute is used.

FACETTING. The making of the facets is rather slow work, especially
when, as is usually the case in making the "table" the work has to be
done against one of the "hard points" of the crystal. Great care has to
be taken to place the stone so that the grain lies in a correct
position