A
special non-metallic cement is used in mounting diamonds for cutting.
It softens and melts when heated over a Bunsen burner, and hardens
immediately when taken away from it. The hardening could also be
hastened by dipping it into water.
The
diamond-cutter has first to remove imperfections and then give the
stones the desired shape or outline with the absolute minimum sacrifice
of the gem. A special chuck is of great assistance to the cutter in
moving the stones to the required position. It could be made eccentric
and brought back to the centre easily. The cutter has to so shape the
stone that it should be attractive and pleasing to the eye. Great care
is also required to collect all powder and fragments, which are of
great value for polishing.
(5) Polishing
The
cutting or grinding of the facets one by one and giving them a good
polish is known as polishing. As has already been described, the facets
must be symmetrically arranged and accurately inclined, which demand
great skill, experience and a keen artistic sense oh the part of the
diamond cutter. Diamond polishers are of two kinds: (1) Lappers, and
(2) Brillianteerers. The lapper cuts the eighteen fundamental facets,
which are as follows: four top corner TC, four bezel facets B, a table
T above the girdle, four bottom corner BC, and four pavilion P facets
and the culet C below the girdle. The facets have to be cut at the
given angles precisely to give the best results.
Then
the stone is passed to the brillianteerer, who adds the remaining forty
facets. Of these eight star S and sixteen top half TH facets are above
the girdle, and the sixteen bottom half BH are below. This finishes a
stone with the usual fifty-eight facets. In cutting these additional
facets, the brillianteerer depends entirely upon his trained eye and
does not use any gauges. Gauges are used by the lapper for cutting the
facets with proper
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