An ideal cut diamond is a round, brilliant, or princess cut diamond that is cut to ideal proportions and angles and has excellent polish and symmetry ratings. An ideal cut diamond reflects almost all the light that enters it, and is among the rarest cuts. The ideal cut diamond is used as benchmark for grading all other diamonds. In America, ideal cut proportions are often determined by the American Gem Society Laboratory (AGSL), but different countries and different companies base their idea of the ideal cut on different standards.
Back in the 1900s, Belgian diamond cutter, Marcel Tolkowsky, coined the term- Ideal Cut. After analyzing the round brilliant cut diamond, he took both brilliance (the amount of the white light reflected) and fire (the separation of white light into its spectral colors) into consideration. While his calculations serve as a guide for today's idea of the global "ideal cut" standards, countries have still made their own modifications.
Tolkowsky's ideal cut is not perfect, but it nevertheless serves as a basic guideline for ideal cut diamonds. Today, we also use the guidelines of a gemstone cutter named Bruce Harding who developed another model in the 1970s as well as other computer models and technological scopes.
Ideal diamonds are perfectly proportioned to refract light, producing that fire and brilliance up through to the table and crown. There are at least six "ideal cuts" being used today but only three of them (including the one by Tolkowsky ) are the most common. James Allen, the premier diamond retailer, offers four cuts of diamonds, two of which are ideal. A TrueHearts diamond is a type of ideal cut diamond.