facets.
The points of these meet the points of sixteen split triangular facets
whose bases rest on the girdle. Between these " lower corner facets "
and the top corner or star facets, are eight lozenge or main facets
whose points reach from the table to the girdle; altogether thirty-two
side facets and the table, thirty-three in all on top. Below the girdle
are sixteen split triangular, or " upper corner on bottom " facets,
whose bases join the corresponding ones on top to form the girdle, and
eight pentagonal main facets extending from the girdle to the culet,
making with the culet, twenty-five facets on the bottom. A diamond cut
thus, if it is properly proportioned, shows an equal distribution of
light and brilliancy at all distances from the eye. The center under
the table is as full of light as the edge facets, because the back
facets are holding the light which has entered from the front. If the
stone were cut too deep or too shallow, part of the light would pass
through the back facets and leave a dark center, called a " well" in a
deep stone, or a "fish-eye" in a shallow stone.
Diamonds
that are too deep to be at their best, are called thick or lumpy
stones, and those that are too shallow are termed " spread " stones if
they show weakness in the center at some distances only, and fish-eyes
if it is everywhere observable. Mr. O. M. Farrand discovered a method
of remedying over-spread stones, by elongating the bottom corner
facets, carrying the points down 3/8 to 7/8 of the distance from the girdle to the culet.
Some
stones are naturally more brilliant than others, but many diamonds
would be more brilliant if cut better. As very many crystals are quite
irregular in shape,
