brilliant

A scattering of "brilliant" cut diamonds shows off the many reflecting facets.

A brilliant is a diamond or other gemstone cut in a particular style with 57-58 facets so as to have exceptional brilliance. The word 'brilliant' is often used for diamonds cut in this style that are round in shape, also known as 'round brilliant cut' or 'standard brilliant cut.' The underside is conical, a shape that provides maximal light return through the top of the diamond. Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is this loss less than 50%. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly-shaped crystals such as macles are more likely to be cut in a fancy cut—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to.