Marcel Tolkowsky (25 December 1899 – 10 February 1991),[1] an engineer by education, was a Belgian member of a Jewish family of diamond cutters from Poland.
[2] Many of his family have gone on to become noted diamond cutters, including his cousin Lazare Kaplan and his great-nephew Gabi Tolkowsky.
Tolkowsky, as part of his PhD topic at the University of London, systematically studied the grinding of diamonds.
[3] Around the same time, in his book Diamond Design, he published the specifications of what would later be called the American Standard (also known as the American Ideal Cut, Tolkowsky cut, and Tolkowsky Brilliant), which is the diamond-cutting benchmark in North America.
[4] The original model was intended to be a set of general guidelines; several aspects of a diamond's cut had not been accounted for or explored.