- Joined
- Jan 8, 2020
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- 85
We were invited to participate in the pilot phase of AGS's return to grading lab diamonds, and we have the results back from our first few batches graded by AGS. Most of the stones we sent were previously graded by IGI or GCAL so I am sharing the results with the community to address the 'conventional wisdom' about IGI grading.
The vast majority of diamonds we submitted to AGS for secondary grading received the same color and clarity grades as their first grading. When AGS differed from IGI or GCAL, the results were only off by one (E vs F color, VS1 vs VS2). More often than not, AGS was looser/easier on the diamonds than IGI/GCAL!
Every lab diamond we have submitted so far received an Ideal 0 grade (for those not familiar with AGS cut grading, they grade from 0-10 with 0 being the best grade).
Here is side-by-side grading comparison of a few lab diamonds. (Mods- please note this is *not* a sales post - my intent is to share a unique chance to look at secondary grading of man made diamonds with the PS community)
If you believe everything you read on the internet, you may believe that IGI and GCAL provide liberal/loose grades. 'Experts' may have convinced you that an F color graded by IGI is actually an H color if graded by AGS, or a VS2 graded by IGI/GCAL should be considered a SI1 or SI2. Our results directly contradict this.
There's a few reasons the conventional wisdom proved to be wrong in our experience so far:
If you do find a diamond that you love, but want the assurance of a grade by GIA or AGS, your jeweler should be able to submit the diamond for secondary grading and lead times are running about 6-10 business days right now.
The vast majority of diamonds we submitted to AGS for secondary grading received the same color and clarity grades as their first grading. When AGS differed from IGI or GCAL, the results were only off by one (E vs F color, VS1 vs VS2). More often than not, AGS was looser/easier on the diamonds than IGI/GCAL!
Every lab diamond we have submitted so far received an Ideal 0 grade (for those not familiar with AGS cut grading, they grade from 0-10 with 0 being the best grade).
Here is side-by-side grading comparison of a few lab diamonds. (Mods- please note this is *not* a sales post - my intent is to share a unique chance to look at secondary grading of man made diamonds with the PS community)
If you believe everything you read on the internet, you may believe that IGI and GCAL provide liberal/loose grades. 'Experts' may have convinced you that an F color graded by IGI is actually an H color if graded by AGS, or a VS2 graded by IGI/GCAL should be considered a SI1 or SI2. Our results directly contradict this.
There's a few reasons the conventional wisdom proved to be wrong in our experience so far:
- Four C's grading of diamonds is not that complicated. IGI and GCAL employ gemologists who are trained and certified by GIA, and those experts aren't actually far off from experts in other grading labs in terms of their assessment of high quality diamonds. They use the same equipment and same techniques to grade diamonds. IMHO, human graders will mostly disappear in the next decade, as AI powered machines are increasingly being used to grade diamonds.
- Cynics might say, the grading labs have been harmed financially by the pandemic and need new business to continue operations. Providing diamonds with liberal grades increases the chances of future business, regardless of whether its lab or mined.
- We didn't submit low-quality lab diamonds for grading. The worse the color and clarity the more likely you'll have grading disparities between labs because the diamonds themselves can vary so much in terms of quality. There is a lot more subjectivity in an I-J-K color than a D-E-F color grade.
- In natural diamonds, high-quality diamonds are rarely graded by IGI or GCAL, where as IGI and GCAL have graded virtually all lab diamonds.
If you do find a diamond that you love, but want the assurance of a grade by GIA or AGS, your jeweler should be able to submit the diamond for secondary grading and lead times are running about 6-10 business days right now.