202 A Book of Precious Stones
The
double brilliant, or Lisbon cut, is a form with two rows of
lozenge-shaped facets, and three rows of triangular-shaped facets,
seventy-four in all.
The
half brilliant, single, or old English cut is the simplest form of the
brilliant and is now generally employed for small stones; when the top
is cut so as to form an eight-pointed star it is called the English
single cut.
The
trap brilliant, or split brilliant, differs from the brilliant in
having the foundation squares divided horizontally into two triangular
facets, forty-two in all.
The Portuguese cut has two rows of rhom-boidal and three rows of triangular facets above and below the girdle.
In
the star cut the table is hexagonal in shape, and is one fourth of the
diameter of the stone; from the table spring six equilateral triangles,
whose apexes touch the girdle, and these triangles, by the prolongation
of their points, form a star.
The
crown of the rose cut consists of trianguÂlar or star facets, whose
apexes meet at the point or crown of the rose. The base lines of these
star facets form the base lines for a row of skill facets whose apexes
touch the girdle, leav-
