Search results
Results from the WOW.Com Content Network
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.
While both reports contain a number of measurements, including dimensions, proportions, carat weight, color, and clarity, the Diamond Grading Report also includes a diamond plot (a graphic representation of the position and type of inclusions present in the diamond). Diamond reports from GIA (as well as other, for-profit sources) are now ...
A diamond's cut is evaluated by trained graders, with higher grades given to stones whose symmetry and proportions most closely match the particular "ideal" used as a benchmark. The strictest standards are applied to the round brilliant; although its facet count is invariable, its proportions are not.
In 1953, Liddicoat introduced the GIA diamond grading system - a practical approach to grading the quality of colorless to light yellow polished diamonds on the basis of color, clarity, and cut. A central feature was the D-to-Z color grading system for faceted colorless to light yellow diamonds—the vast majority of diamonds seen in the trade.
Several different theories on the "ideal" proportions of a diamond have been and continue to be advocated by various owners of patents on machines to view how well a diamond is cut. These advocate a shift away from grading cut by the use of various angles and proportions toward measuring the performance of a cut stone.
In 1919, Lazare Kaplan's cousin, mathematician Marcel Tolkowsky, first published the mathematical formula for diamonds cut to "ideal" proportions, a formula designed to optimise the brilliance, fire and sparkle in a polished diamond. In the same year, LKI became the first commercial-scale operation to cut its diamonds to ideal proportions.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
It is, on the Gemological Institute of America (GIA) color and clarity scales, a D grade (colorless to the highest grade), IF (Internally Flawless, flawless to the second highest grade) diamond (in short: a DIF or a DIF diamond) and the largest DIF ever graded at the GIA; and it is of type IIa (as determined by the Gübelin Gem Lab of Lucerne ...