The Round Brilliant cut has 56 or 57 facets:
8 Bezels / 8 Stars
16 Halfis of Crown
16 lower girdles
8 Pavilions (or Cylinder Heads)
1 Culet (not systematic)
Rough diamond :
The rough diamond can be either of an octahedron form (8 faces) or of a dodecahedron form (12 faces).
A perfectly cut diamond requires more loss of crude, up to 60% to 70%, while a good size, barely half.
The diamond cutter has a strategic choice to make between a perfectly proportioned diamond that would be smaller, or a larger diamond that would refract less light.
The choice of proportions, shape and size of the stone will be based on the inclusions, weak points and shape of the rough diamond.
Marcel Tolkowsky Inventor, mathematician of the Brilliant Rond cut in 1919, Antwerp, Belgium.
The proportions of the round brilliant diamond are reviewed in order to maximize the light in the stone. (the reflection of the light in the stone?)
- Ancient India (+/- 5000 years) and Antiquity: rose cut or not faceted, only polished
- Middle Ages: Europe, the stone is polished following the shape of the raw stone "taille en Pointe"
- 14th century: Nuremberg, Germany, table cut and culet called "Writting Diamonds", "Point Cut" or "Table"
- 16th century: Lodewyk van Berken in Bruges, Belgium, invents the "scaif" tool for faceting and polishing diamonds. The tool has been modernised, but is still used. Invention of the absolute symmetry ("Size not cut") then of the "Mazarin size"
- 17th century: Vincenzo Peruzzi, Venice, Italy, invents the brilliant cut and the "Old Size" cut
- 20th century: Marcel Tolkowsky, Antwerp, Belgium, revolutionizes the art of diamond cutting