Gem-Stones and Their Distinctive Characters — John Shaqi
Gem-Stones and Their Distinctive CharactersSmith, George Frederick Herbert
Science
Gem-Stones and Their Distinctive Characters
Smith, George Frederick Herbert
Precious stones
The brilliant form is derived from the old table by increasing the
number of facets and slightly altering the angles pertaining to the
natural octahedron. In a perfect brilliant (Figs. 47-49) there are
altogether 58 facets, 33 above and 25 below the girdle, as the edge
separating the upper and lower portions of the stone is termed, which
are arranged in the following manner. Eight star-facets, triangular
in shape, immediately surround the large table-facet. Next come four
large templets or bezels, quadrilateral in form, arranged in pairs
on opposite sides of the table-facet, the four quoins or lozenges,
similar in shape, coming intermediately between them; in modern
practice, however, these two sets are identical in shape and size,
and there are consequently eight facets of the same kind instead of
two sets of four. The eight cross or skew facets and the eight skill
facets, in both sets the shape being triangular, form the boundary
of the girdle; modern brilliants usually have instead sixteen facets
of the same shape and size. The above 33 facets lie above the girdle
and form the crown of the stone. Immediately opposite and parallel to
the table is the tiny culet. Next to the latter come the four large
pavilion facets with the four quoins intermediately between them,
both sets being five-sided but nearly quadrilateral in shape; these
again are usually combined into eight facets of the same size. Eight
cross facets and eight skill facets, both sets, like those in the
crown, being triangular in shape, form the lower side of the girdle;
these also are generally united into a set of sixteen similar facets.
These 25 facets which lie below the girdle comprise the ‘pavilion,’
or base of the stone. In a regular stone properly cut a templet is
nearly parallel to a pavilion, and an upper to a lower cross facet. The
contour of the girdle is usually circular, but occasionally assumes
less symmetrical shapes, as for instance in drop-stones or pendeloques,
and the facets are at the same time distorted. The number of facets may
with advantage be increased in the case of large stones. An additional
set of eight star facets is often placed round the culet, the total
number then being 66. It may be mentioned that the largest stone cut
from the Cullinan has the exceptional number of 74 facets.
[Illustration: FIG. 47.—Brilliant Cut (top view).]
[Illustration: FIG. 48.—Brilliant Cut (base view).]
[Illustration: FIG. 49.—Brilliant Cut (side view).]
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