GIA’s Diamond Cut Grade Described

The essentials of the Gemological Institute of America’s cut-grading system for round brilliant diamonds, in effect since Jan. 1, were described to a rapt audience of some 250 jewelers and others by Phil Yantzer and Barak Green (pictured) of the Gemological Institute of America on Thursday during the two-day education conference preceding The JCK Show ~ Las Vegas. Yantzer is the laboratory director, West Coast grading, for the GIA Gem Trade Laboratory, in Carlsbad, Calif. Green is the Gem Trade Laboratory’s manager of communications. The presentation was designed to “help you understand how to use the cut-grade system in daily business, with your customers and in your own labs,” said Green. The new system applies to all brilliants on the GIA D-to-Z color scale and the Flawless-to-I 3 clarity scale. It caps 15 years of work, study, and research, including some 70,000 diamond observations, 2,300 diamonds, and some 300 observers in the diamond industry.There are five cut grades: excellent, very good, good, fair, and poor. Most diamonds are in one of the top three. The system’s merits, noted Green, are that it’s “science-based, accessible, practical, predictable, comprehensive and incorporates a consumer diamond buyer’s taste or preference.” For more information, visit

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