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Diamond proportions and facets, for the round brilliant cut. The modern round brilliant-cut was developed by Marcel Tolkowsky in 1919. The ideal proportions are 100% diameter, 53% table, 43.1% pavilion and 16.2% crown. The girdle and culet (if any—not part of Tolkowsky's original design) are cut from the ideal brilliant.
Diamond proportions and facets, for the round brilliant cut. The modern round brilliant (Figure 1 and 2) consists of 58 facets (or 57 if the culet is excluded); 33 on the crown (the top half above the middle or girdle of the stone) and 25 on the pavilion (the lower half below the girdle). The girdle may be frosted, polished smooth, or faceted.
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.He is generally acknowledged as the father of the modern round brilliant diamond cut. [2]
"Ideal" round brilliant diamonds should not have a depth percentage greater than 62.5%. Another quick indication is the overall diameter. Typically a round brilliant 1.0-carat (200 mg) diamond should have a diameter of about 6.5 mm (0.26 in).
Princess cut diamond set in a ring. The princess cut (technical name 'square modified brilliant') is a diamond cut shape often used in engagement rings. The name dates back to the 1960s, while the princess cut as it exists was created by Betazel Ambar, Ygal Perlman, and Israel Itzkowitz in 1980.
It was cut to 1.09 carats (220 mg) in 1997, and graded a "perfect" 0/0/0 by the American Gem Society (AGS) in 1998 and graded perfect by the Gemological Institute of America, making it the first diamond from Arkansas to receive such an AGS grading. The diamond is considered one-in-a-billion, according to Peter Yantzer, the AGS Laboratory Director.
Color grading of diamonds was performed as a step of sorting rough diamonds for sale by the London Diamond Syndicate. As the diamond trade developed, early diamond grades were introduced. Without any co-operative development, these early grading systems lacked standard nomenclature and consistency. Some early grading scales were; I, II, III; A, AA, AAA; A, B, C. Numerous terms
Lab-grown diamonds of various colors grown by the high-pressure-and-temperature technique. A synthetic diamond or laboratory-grown diamond (LGD), also called a lab-grown diamond, [1] laboratory-created, man-made, artisan-created, artificial, synthetic, or cultured diamond, is a diamond that is produced in a controlled technological process (in contrast to naturally formed diamond, which is ...