Cutting Diamonds and Other Gems 201
ness of the fundamental octahedron; the bottom facet is called the owlet, or collet, and is formed by removing one eighteenth part of the stone's thickness. The triangular facets touching the table or summit of the crown are called star facets; those touching the girdle are divided into two groups, skill facets and skew facets.
The corner facets touching the table and the girdle, when on the crown,
and the culet and girdle, when on the pavilion, are called,
respectively, bezel or bizel facets, and pavilion facets.
A summary of the number of facets and their distribution is as follows:
1 table, 16 skill facets, 16 skew facets, 8 star facets, 8 quoins, 4
bezel facets, 4 pavilion facets, and one culet. Sometimes the cut is
modified by adding extra facets around the culet, making sixty-six in
all. The brilliant cut is especially applicable to the diamond; when
perfect it should be proportioned as follows: From the table to the
girdle, one third, and from the girdle to the culet two thirds of the
total. The diameter of the table should be four ninths of the breadth
of the stone. These proportions when applied to other stones than the
diamond are modified to suit the individual optical constants of the
gem.
