Shh.. the secret to why diamonds in jewelry stores aren't GIA certified
“Can you think of a good reason why the diamonds in “*” store are not GIA certified? I was absolutely floored by the fact that “*” company doesn’t use an independent laboratory to certify their diamonds! The sales clerk told me that they rely on the expertise of their in-house gemologists? Somehow that doesn’t make me feel confident about buying a diamond from them. It seems a lot like that old fox guarding the hen house type of thing. Am I just being paranoid, or is the practice of grading diamonds in-house standard industry practice? I notice that Brian Gavin uses the AGS Laboratory, can you tell me more about that? How do they compare to GIA?”
GIA vs AGS diamond grading reports:
If you’ve been shopping for a diamond for any length of time, then you’re probably familiar with the Gemological Institute of America (GIA). The GIA seems to enjoy prominent status in the market, because they are considered to be the gemological authority. Arguably this might simply be because they’ve been around the longest, and trained most of the gemologists working in the diamond industry. The fact of the matter is that the GIA and American Gem Society (AGS) were both started by Robert M. Shipley. Initially the purpose of the GIA was to provide gemological education and grading services, while the AGS was intended to be the moral backbone of the industry.
During the mid-1990’s the American Gem Society (AGS) decided to open a gemological laboratory of their own, and they recruited GIA Lab Director Peter Yantzer to run it. The defining difference between the two gemological laboratories at the time, was that the AGS Diamond Quality Document (DQD) focused on diamond cut quality and proportions. At the time, GIA diamond grading reports did not provide crown or pavilion measurements.
It took the GIA Gem Trade Laboratory about 10 years to catch up and provide more complete proportions details on their diamond grading reports. The GIA updated the content featured on their diamond grading reports in 2005, just a week or two before the AGSL announced the launch of their new Light Performance based grading platform.
AGS Ideal-0 vs GIA Excellent cut diamonds:
The two diamond grading reports included in the graphic provided above are a GIA diamond grading report (left) and an AGS Diamond Quality Document (right) for the same Brian Gavin Signature round diamond. This diamond weighed 1.25 carats and was graded by both gemological laboratories as being D-color with internally flawless clarity.
The GIA diamond grading report number is 2145936424 and the AGS diamond quality document number is 104068744001. The overall cut grade is GIA Excellent and AGS Ideal-0 accordingly.
Brian Gavin has sent diamonds to be dual graded or what is commonly (and incorrectly) referred to as “dual certified” on multiple occasions. Each time the carat weight, color, clarity, fluorescence rating, polish, symmetry, and overall cut grade has come back the same. Keeping in mind of course that the AGS and GIA use different terms to describe fluorescence and their highest grades for polish, symmetry and proportions.
The primary difference that distinguishes the two labs at this time is that the AGS uses proprietary Angular Spectrum Evaluation Technology (ASET) to determine the light performance of Brian Gavin Signature diamonds. Unfortunately, the GIA doesn’t use any kind of technology to judge light performance, their cut grade only takes proportions, polish and symmetry into account.
Why doesn’t “*” jewelry store use the GIA?
We really don’t know why “*” jewelry store doesn’t use the GIA or the AGS Laboratory to grade the diamonds that they offer… that’s something that you’ll need to take up with them. Obviously we’re just as capable as the diamond graders at the AGS or GIA to determine the characteristics of the diamonds that we sell. But it seems to us that providing our clients with an independent evaluation of the diamond, provides a certain peace of mind.
The initial purpose of the diamond grading scale developed by the Gemological Institute of America was to provide the industry with a consistent standard for diamond grading. The AGS Laboratory offers the same consistent grading standards, and expands upon them by providing the additional insight to be gained by ASET. We wouldn’t expect our clients to accept anything less.
P.S. we don’t really like to use the term GIA Certified Diamonds or promote the misnomer of certified diamonds, because the GIA and AGS do not certify diamonds. Gemological laboratories issue diamond grading reports, which describe the characteristics of the diamond at the time it was graded. The gemological laboratories do not actually certify anything, and a statement to that effect appears on the back of both GIA and AGS diamond grading reports.