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THE ART OF THE CUTTER
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the directions of cleavage or, to get technical about it, the
position of the underlying octahedron. The lapidary's aim,
after all, is to form the largest possible stones out of the
piece entrusted to him. The chief use of the cleavage
method is to free the rough mass of any awkward or useless
excrescence or to enable the cutters later to eliminate the
flaws without too much wastage of material. While the
octahedron, for example, is one of the common forms in
which the diamond crystallizes, it is seldom regular in
shape unless quite small. Usually the most suitable "face"
of the octahedron is selected to serve as the table facet of
the resulting brilliant. The rough mass is described as of a
particular "point," according to the relation of the table
to the underlying regular octahedron. The mass is said to be
four-point if the table is cut parallel to the face of the cube
(that is, across a corner of the octahedron so that the
resulting section is square); three-point, or Wass, if the
table is parallel to an octahedron face; two-point, if the
table is parallel to a face of the dodecahedron and therefore
to an edge of the octahedron, while equally inclined to its
two faces meeting in that edge.
These
things admittedly may be highly technical to the average lay reader but
they must be mentioned just in case some technical authority on the
subject is lurking behind the pages of this book waiting for "flaws."
What they come down to is this:
Since
the hardness of a diamond varies perceptibly with the "direction" in
the crystal, it is important that the cutter determine the point of the
"mass" before beginning to work on it. So it is more essential to take
his precious time than to make a hasty decision, for it would be
disastrous if the stone should split in the wrong direction or if
flaws should develop. But once the position of the cleav-
(85)
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