No offense to the Tolkowsky family, but if you thought that Marcel was the father of the Ideal cut diamond, then you should have heard Al Gilbertson’s “American Cut: How a Group of Enterprising Americans Made Diamonds More Beautiful.”

Gilbertson, a research associate at the Gemological Institute of America and an expert in diamond cut grading, has been researching the Ideal cut for the past several years. He shared with his audience the evolution of the Ideal cut from its earliest beginnings, from the mid 1800s, and explained why it used to be called the American cut.

Since many in the trade attribute the Ideal cut design—and even its name—to Marcel Tolkowsky and his 1919 doctoral thesis, Gilbertson finds himself swimming against the current. Nevertheless, he talked about what he uncovered, what really happened “back then,” and who deserves credit.

“What Tolkowsky wrote was just a book—not a thesis,” said Gilbertson. “The Ideal cut was already in use in the U. S. by 1903 and was synonymous with the terms “American cut” and “scientific cut.” The proportions Tolkowsky espoused were nearly identical to the ones already in use as the American cut, except that the table size was significantly different.”

As early as 1903, ray tracing had shown that the proportions of the American cut were superior. “Frank Wade, one of the leading experts in the trade, helped establish the parameters of the American cut,” said Gilbertson. “But it was Herbert Whitlock in 1917 who published the most about ray tracing, demonstrating the superiority of the American cut.” This was, of course, two years prior to Tolkowsky’s book.

“It was called the American cut due to the efforts of Henry Morse, a diamond cutter in Boston, who, by 1873, had built a machine that made a diamond perfectly round,” Gilbertson explained. “This was the first bruting machine. Prior to this, diamonds were rarely cut as round shapes. Morse also made the first gauge to measure the angles of diamonds and through repeated experiments decided which angles were the best for the crown and pavilion.”

Other cutting factories sprang up in America, copying his methods, and, by 1900, Morse’s style of cutting was called the American cut.

The new cutting style was soon being followed all over the world, and for some time it was called American cut. Tolkowsky’s 1919 book influenced the leading experts in America; they modified their cutting style by matching his table size.

“GIA’s introduction of gemological training in the 1930s further spread the terms and proportions of the Ideal cut,” said Gilbertson. “And it was in 1953 that GIA’s Richard Liddicoat introduced the first cut-grading system at the same time he introduced what would become the international system for color and clarity grading, based on the proportions of the American cut.”

So, don’t throw out that Tolkowsky Ideal cut T-shirt yet, but realize that the names Morse, Whitlock, and Wade also should be attached to the Ideal cut diamond.

JCK