- American Cut
- Those proportions and facet angles calculated mathematically by Marcel Tolkowsky to produce maximum brilliancy consistent with a high degree of fire in a round diamond brilliant are considered by many diamond men to constitute the ideal cut. These figures, computed as a percentage of the girdle diameter, are as follows: total depth, 59.3% (without provision for girdle thickness); crown depth, 16.2%; pavilion depth, 43.1%. The bezel angle is 34° 30’ and the pavilion angle is 40° 45’. Girdle thickness as a percentage of the girdle’s diameter varies with size. The larger the stone, the smaller the percentage for a medium girdle. The variation is from about 1% to 3%.