to measure light behavior. DGLA in the US and Mumbai, India, PGGL in the US and EGL-USA are both offering versions of this grading in 2008. DGLA has graded thousands of diamonds with this promising direct assessment technology. "Brilliancescope" by Gemex is another assessment light behavior technology in use by many US and now foreign retailers and diamond cutters. Effect of cut on other diamond characteristics During the diamond cutting process, the diamond cutter wants to get the heaviest diamond out of a rough stone. However, this can come at the cost of lowering cut grade. If a diamond is too deep, the carat weight increases with a loss of brilliance due to light leakage. Diamond cutters have to contend with working a stone to its best finished form with the least amount of waste. This strategy depends on the quality of the stone and its final proportions. If two diamonds of equal weight are inspected there can be a noticeable difference in size when viewed from above; arguably the most important view. A well cut 0.90ct diamond for example could have the same width as a poorly cut 1.00ct diamond. This phenomenon is known as spread. Cut also affects the color of a diamond. This is especially important when considering fancy colored diamonds, where the slightest shift in color could vastly affect the price of the diamond. Most fancy colored diamonds are not cut in to round brilliants, because whereas the round brilliant is prized for its ability to reflect white light, the most important characteristic in a fancy colored diamond is its color, not its ability to reflect white light. See also List of gemstone cuts Brilliant (diamond cut) Cut (gems) Diamond clarity Diamond color Diamond cutting Diamond enhancement Diamond simulant Famous diamonds Material properties of diamond Princess cut Synthetic diamond References Further reading Antique Jewelry University – A History of Diamond Cutting Bruton, Eric. (1979). Diamonds, 2nd ed. Chilton Book Co. Cipriani, Curzio, Borelli, Alessandro, and Lyman, Kennie (US ed.) (1986). Simon & Schuster's Guide to Gems and Precious Stones, pp. 58–68. Simon & Schuster, Inc.; New York, New York. Malecka, Anna (2017). Naming of the Koh-i-Noor and the Origin of Mughal-Cut Diamonds, The Journal of Gemmology, no. 4. 38(8). Pagel-Theisen, Verena. (2001). Diamond grading ABC: The manual (9th ed.), pp. 176–268. Rubin & Son n.v.; Antwerp, Belgium. OctoNus Software has posted several diamond cut studies, by