AGS to use new performance-based system to issue diamond cut grades

The American Gem Society Laboratories said Wednesday they would begin issuing the Diamond QualityTM Document for the new AGS performance cut grade system on round brilliant cut diamonds starting June 1. The announcement was made at the AGS Conclave in Hollywood, Calif., by Peter Yantzer, executive director of AGS Laboratories.

For a ninety-day period, clients will be offered the current proportions-based DQD or the new performance-based DQD. Effective September 1, the Lab will only issue DQDs with the new performance-based system.

In the new performance-based system, all 58 facets of the diamond are measured in three dimensions rather than two dimensions. The lab will use state-of-the-art ray tracing software to trace light traveling through a diamond. The software demonstrates the quantity and quality of the light being returned to the viewer. AGS Laboratories will now consider brightness, dispersion, leakage, contrast, and weight ratio, in addition to proportions, symmetry, and polish, when assigning a final cut grade.

“Because a diamond’s cut is the most important factor in how it performs, AGSL is committed to using the most advanced technology and science when it comes to assessing and grading cuts,” Yantzer said. “The results of this research further validate Marcel Tolkowsky’s theory on diamond cut.”

The lab recently announced that they would release their new fancy shape cut grading system at the beginning of May. Concurrent with that event, the lab will launch a new look for all their document packaging.

The lab’s Web site features a preview of the new packaging at More information is also available by emailing AGS at

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