A US grading laboratory has introduced a new cut grade designed to differentiate higher-quality diamonds from the “excellent” score that most polished stones receive.

Gem Certification & Assurance Lab (GCAL) unveiled its 8X grading report this week, highlighting a need to set apart premium-cut diamonds from the rest.

“Superior and precision-cut diamonds have been getting lost in the shuffle, identified with, and confused with, lesser-quality diamonds,” Don Palmieri, president of GCAL, said in a Zoom presentation on Tuesday. “Consumers are looking for the best of the best diamonds, but it’s becoming more difficult for retailers to identify those premium diamonds.”

The Gemological Institute of America (GIA) introduced its cut grading system in 2005, assessing the cut, polish and symmetry of each diamond. For each parameter, the GIA uses a scale of five qualities: excellent, very good, good, fair and poor.

GCAL estimates that about 85% of diamonds today receive a triple excellent (triple Ex) grade, with more stones able to achieve that highest ranking as technology used in the cutting process has improved. Manufacturers have expressed frustration that the craftsmanship and precision of their premium-quality diamonds are not being recognized, Palmieri noted.

That prompted GCAL to develop its 8X program, analyzing “hundreds of thousands of diamonds” to identify the strict, exacting tolerances to achieve the ultimate precision-cut diamond, the company explained.

To qualify as an 8X diamond, the stone must receive an excellent grade for all eight parameters set out in its report. They include polish, external symmetry, proportions, optical brilliance, fire, scintillation, optical symmetry, and hearts and arrows.

The requirements on polish, symmetry and proportions are stricter than that of the GIA’s triple Ex standard, GCAL stressed.

GCAL expects an 8X diamond to sell for a premium over non-8X stones, though the company would not speculate on how much more it could garner.

The cutting requirement is greater “and there’s more labor to achieve the precision required to be an 8X diamond, so there will be a premium over a standard round brilliant diamond that gets a triple Ex,” explained chief operating officer Angelo Palmieri.

The 8X certificate will be available in both print and digital format and will use video imaging to demonstrate various parameters. GCAL will also offer it for lab-grown diamonds.