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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.
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.
The Acropolis of Athens (468–430 BC), including the Parthenon, according to some studies, has many proportions that approximate the golden ratio. [10] Other scholars question whether the golden ratio was known to or used by Greek artists and architects as a principle of aesthetic proportion. [ 11 ]
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]
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.
As Novalis put it, "The musical proportions seem to me to be particularly correct natural proportions." [3] Alternatively, it can be described as the tuning of the syntonic temperament [1] in which the generator is the ratio 3:2 (i.e., the untempered perfect fifth), which is ≈ 702 cents wide. The system dates back to Ancient Mesopotamia;. [4]
A golden rectangle with long side a + b and short side a can be divided into two pieces: a similar golden rectangle (shaded red, right) with long side a and short side b and a square (shaded blue, left) with sides of length a.