Where diamond grading reports from AGSL / GIA fall short

While the diamond grading reports which are issued by top tier gemological laboratories such as the American Gem Society Laboratory (AGSL) and the Gemological Institute of America (GIA) are invaluable tools which provide consumers with an impartial opinion of the characteristics of the diamond which they are considering, including an overall cut grade which is a step in the right direction.

However there is a lot of information that is not provided on the diamond grading reports issued by the AGSL and GIA, which might affect a consumers decision to purchase one “GIA Excellent Cut Diamond” over another, or one “AGS Ideal Cut Diamond” over another, if the critical factors of diamond cut grading were made readily available on the diamond grading reports.

It might also provide consumers with a better understanding if it were explained that the symmetry grade provided on a diamond grading report, is an indication of meet point symmetry and not optical symmetry. Meet point symmetry refers to how well the facet junctions meet up with one another, while optical symmetry refers to the consistency of facet shape and precision of alignment.

Scopes used to judge optical symmetry in diamonds:

Those of us who focus on producing and selling diamonds of extremely high cut quality, use different reflector scopes to judge the optical symmetry of diamonds.

One of those scopes is a desktop version of the Angular Spectrum Evaluation Technology (ASET) developed by the AGSL, which is used by them to judge the brightness and cut quality of diamonds graded under their Light Performance grading platform. While the AGSL provides the results of their scan on the diamond grading report which they issue for our diamonds, we also provide an image of the diamond as seen through the ASET scope that we use as part of our diamond evaluation process.

Using an Ideal Scope to evaluate light leakage:

We also use an Ideal Scope to judge the optical symmetry of the diamond, and the degree to which it is leaking light, with the understanding that all diamonds leak light to some degree, but that some leak more light than others.

The reference chart, featured at the top of this page and provided by the company which sells the ideal scope, provides a visual reference of how diamonds of different cut qualities might appear when viewed while unmounted through an ideal scope.

If you look at the ideal scope images for the diamonds in our inventory, like this 1.686 carat, I-color, VS-2 clarity, Brian Gavin Signature round diamond, you’ll see that they look exceptional when viewed through an ideal scope.

Hearts & Arrows is a reflection of optical symmetry:

We also use a Hearts and Arrows Scope to demonstrate the superior level of optical symmetry and cut quality exhibited by our Brian Gavin Signature round diamonds, because the presence of a crisp and complete pattern of Hearts and Arrows is an indication of higher cut quality. As you can see by the picture provided to the left, the 1.686 carat, I-color, VS-2 clarity, Brian Gavin Signature round diamond also exhibits a crisp and complete pattern of Hearts & Arrows. The combination of the details provided on the DQD issued by the AGSL, and the different scope images, clearly indicate that this diamond offers superior diamond cut quality.

However this information is not provided on diamond grading reports issued by the AGSL or the GIA, and the majority of online diamond vendors and jewelry stores do not provide it either, and thus the majority of people end up making their diamond buying decision, armed with only a fraction of the information necessary to make an informed choice.

Arguably, the diamond grading reports issued by the AGSL which feature the results of the Angular Spectrum Evaluation Technology (ASET) scan, provide more insight than the basic details provided on a diamond grading report issued by the GIA, however it still does not provide a complete representation of the diamond’s cut quality.

Brian Gavin Diamonds makes every effort to provide our clients with all of the information necessary to make an informed decision while buying a diamond online, our diamond details pages offer extensive detail and insight into diamonds which we offer. Each page is complete with a high resolution video of the diamond, a clarity photograph, a copy of the diamond grading report, and images of the diamond as seen through the various reflector scopes used to judge optical symmetry and diamond cut quality.