Sapphire Amber Emerald Crystal Heart Diamond Set of 12 40mm These gem Pieces are shaped using the Round Brilliant Cut This design was developed by Marcel Tolkowsky, an engineer from a family of diamond cutters. Tolkowsky mathematically calculated the properties of light and how it reflects and refracts within a diamond This is also known as the American Standard Cut and is the common cut design in North AmericaAll of the gems we carry are shaped using this cutting method They can also be used as centerpieces for special events and ceremonies. Brand New100%