Diamonds Update

The American Gem Society (AGS) Laboratories, headquartered in Las Vegas, announced they will begin including their cut grade on Diamond Quality Documents for emerald cut diamonds February 1, 2007.  The AGS had previously announced they would be including the cut grade for emerald cuts, but only recently established a date when they would start.

The cut grades will be included for three emerald-cut shapes: square emerald, rectangular emerald cut and the octagon step cut.  The AGS had introduced their Performance-Based Cut Grade System in 2005, first with round brilliant diamonds and then for princess cuts.

Most other cut grading systems are proportion-based which use external measurements of the diamond to determine the cut grade.  By contrast, the AGS’s Performance-Based Cut Grade System includes the light performance of the diamond by estimating the movement of light through the diamonds and establishes a cut grade based on the brightness, dispersion, leakage, contrast and weight ratio, as well as the proportions, polish and symmetry.

Because the AGS’s Performance-Based Cut Grade System makes it easier to establish cut grades for different shaped diamonds, we would expect to see the AGS Laboratory establish cut grades for many of the common fancy shapes in the next several years.