AGS's New Issues in Diamond Grading

This year, the American Gem Society ( introduces improvements into the existing grading system. After years of research on a fancy shape cut grade project, using new knowledge on diamond optics, AGS created an advanced system that will make it possible to grade fancy shape diamonds. In the light of this research, AGS performed also a re-evaluation and improvement on its existing grading system for the brilliant cut.

Princess Cut -- First Scientific Grading for a Fancy Shape

Starting May 1st, AGS releases industry's first scientific cut grade for the princess cut.

AGS Laboratories use high-end technology to measure all facets of a diamond in three dimensions and software for tracing light traveling through a diamond. Thus not only the quantity but also the quality of the light being returned to the viewer is analyzed.

The Procedure

The diamond will be scanned by a Sarin machine. The detailed measurements of the angles will then be entered into a computer and a 3D image will be created. The degree of brilliance and fire will be revealed by performing a ray tracing analysis of the virtual diamond.

The grading system will assign a grade from zero -- for the best/ideal -- to ten -- for the worst stones.

The grading is performance-based and will make the difference between fancy-shaped diamonds with a better light performance by measuring brightness, leakage, dispersion, contrast and weight ratio (in addition to the already existing grading parameters -- proportion, symmetry and polish).

AGS intends to implement further the new grading system for other fancy shapes.

On this date, AGS will launch as well a new look for its document packaging.

Brilliant Cut -- New Grading Parameters

Beginning with June 1st, the Diamond Quality Document (DQD) for brilliant cut diamonds will contain new quality parameters, namely performance cut grades.

After a five-year work on the AGS fancy shape cut-grade research project, the results and technology that were obtained permitted improvement of the round brilliant cut-grading scale.

The same machinery is used in round brilliant diamonds assessment and the same factors are taken into account: Besides proportion, symmetry and polish, the cut grade will include performance parameters, such as brightness, leakage, dispersion, contrast, and spread.

Starting September 1st only the new Diamond Quality Documents will be issued and until this date clients have the possibility of choosing between the new system and the current one.