The classic round cut, also known as the Tolkowsky ideal cut, is considered the ideal shape for enhancing the aesthetic brilliance and intensity of a diamond. With widespread popularity, the round brilliant cut accounts for up to 75% of diamonds sold today due to its versatility.

The classic round cut, with its 58 facets distributed across crown, girdle, and pavilion and a ratio typically between 1.00 and 1.02, optimizes the natural qualities of diamond crystals. It is extensively researched, with professional diamond cutters employing advanced scientific theories and intricate mathematical models since the early 20th century. Achieving maximum sparkle requires cutting a significant portion of the rough stone, contributing to the relatively higher price of these stones.

Although originating in 17th-century Europe, the round cut is sometimes referred to as the American Ideal Cut. The initial brilliant cuts, known as Mazarins, were named after Cardinal Mazarin, the designer of the breakthrough cross-cut diamond in the mid-1600s. Evolving through the 18th century, Mazarin's design transformed into the Portuguese Peruzzi or 'old mine' cut. The modern round brilliant, known as the Tolkowsky, emerged in 1919, named after its inventor, Belgian engineer Dr. Marcel Tolkowsky. Dr. Tolkowsky hailed from a lineage of Polish-Jewish diamond cutters, with his cousin Lazare Kaplan and great-nephew Gabi Tolkowsky continuing the tradition, marking the sixth generation in the family trade.