The cut of a diamond holds the main responsibility for the radiance and fire of a diamond, and is also the only factor influenced by man.
Tolkowsky Ideal Cut diamonds have proportions that truly bring out their radiance and light. Named after their inventor Marcel Tolkowsky in 1919, these diamonds make up the benchmark still used today to judge all diamonds. All Tolkowsky Ideal Cut diamonds carry the ‘Ideal’ cut specifications on the diamond certification, the highest possible grade.
Tolkowsky designed the traditional 58 facet round brilliant diamond. Leo Schachter branded the 66 facet round brilliant as the Leo Diamond in 1999. Having 8 more facets than the traditional 58, found in the bottom half of the diamond, Leo Diamonds are deemed a “modified round brilliant” cut diamond. Since these diamonds are only found in select stores and have a GSI grading report, it is difficult to compare them with the normal 58 facet diamond with a GIA or AGS grading report.
Not all Leo Diamonds have the same cut quality, however; some are better than others. In addition, since they are sold in limited stores, most Leo Diamonds cost more than traditional round brilliant diamonds.
Courtesy of Tolkowsky & Online Diamond Buying Advice