This is a brilliant-cut triangle diamond - a wedge shape with fiery brilliance. It can be a traditional triangular shape with pointed corners, or a more rounded triangular shape. Trillions (also called Trilliants or Triangles) are often used as diamond accents in three stone rings and other jewelry settings, but may also be chosen to be set as solitaire diamonds.
This is a spectacular wedge of brittle fire. First developed in Amsterdam, the exact design can vary depending on a particular diamond's natural characteristics and the cutter's personal preferences. It may be a traditional triangular shape with pointed corners or a more rounded triangular shape with 25 facets on the crown, 19 facets on the pavilion, and a polished girdle. It is definitely for the adventurous.
Length to width ratio: An equilateral triangle is prefered in a trillion diamond. Variance in the ratio of length to width should not deviate considerably.