Bridal Jewelry 2007 Diamond Grading Report Case Study:
Comparing EGL-International Vs. GIA Vs. AGS Vs. EGLUSA in the Diamond Grading of a 1-Carat Stone.Introduction
There are some vendors out there that want nothing to do with EGL graded diamonds. Why is that? While it’s true some EGL labs (especially the International ones such as Israel, etc) are less strict compared to GIA or AGA, many of the EGL-USA graded diamonds can be accurately graded. However this isn’t always the case with the larger and rarest diamonds. So how do the lab grades compare between EGL International or EGL USA or GIA or AGS?
That brings us to this study we conducted. We had absolutely no idea what the outcome would be. In fact the selection of this diamond had nothing to do with me it was the choice of a woman who was a novice on diamond grading. We had a total of 7 diamonds shipped in for her to pick from and I decided I was going to do a study on the one she picked, I never even looked at the diamond personally, I selected them based on their grading reports alone. Based on her request they were all roughly worth the same amount.
So anyhow of the 7 for her to pick from were 2 AGS 000 diamonds, 2 GIA Excellent cut grade diamonds, 2 EGL Israel "Ideal Tolkowsky" diamonds, and 1 EGL-USA "Ideal Plus" diamond. All were roughly the same wholesale price (different color/clarity combinations) and she chose one of the EGL-Ideals because it had the brightest color and to her had the best of what she wanted. I had hoped she picked a warmer color AGS-000 but that was her decision. Anyhow off to GIA that diamond went!
GIA took 5 weeks to grade this one diamond. (Why do they need to hold on to the diamond for so long??? Oh well). After it came back from GIA it was sent to AGS where it was literally graded in 3 days and returned to me on the fourth. They faxed me all the details and asked me which report I wanted.... the one with all the info and light performance or the regular report with just proportional grading (that all the under-performers usually get). I knew the stone was not AGS000 worthy, but I wanted the full report, don't hold anything back! So that's what I got. Wow, interesting results compared to GIA I noticed (I still didn't look at the diamond) But on to the next lab! I wanted EGL-USA's top report as well. So I found out they had a combined EGL-GEMEX grading report and that's what I opted for, but I had to send it to New York instead of just dropping it off here in LA (bummer!). But I did so regardless. Turns out when it gets there they just canceled their GEMEX cooperative grading just before my stone arrived. So I was told outdated information just as my diamond was flying over the big apple. (another bummer!) Oh well, the good news is that they developed their own light performance grading report (their new "360 Diamond Report") and their machine was to arrive a few weeks later, and they were even going to run my diamond before anyone else has even seen this new report! I’ll be the first in the industry to have one because of the GEMEX mixup. Wow, I feel so honored, and of course I let them keep the stone for a few weeks so they could fire up their new machine. So even though they had the diamond for 3-1/2 weeks, the grading normally would have been done in under a week.
Results
| EGL-Int'l (Israel) | GIA (Carlsbad) | AGS | EGL-USA (NY) | |
| Carat | 1.02cts | 1.02cts | 1.020cts | 1.02cts |
| Color | D | D | E | E |
| Clarity | SI1 | SI2 | SI2 | SI2 |
| Dimensions | 6.63x6.56x3.92 | 6.57x6.64x3.95 | 6.57x6.64x3.94 | 6.74x6.57x3.94? |
| Depth% | 59.4 | 59.8 | 59.7 | 59.6 |
| Table% | 54 | 55 | 55.0 | 55-57? |
| Crown Angle | ------N/A------ | 31.5 | 31.7 | 31.5 |
| Crown % | 14 | 14.0 | 14.1 | 13.9 |
| Pavilion Angle | ------N/A------ | 41.0 | 40.9 | 41.0 |
| Pavilion % | 43 | 43.0 | 43.2 | 44.0-43.1? |
| Polish | Very Good | Very Good | Very Good | Very Good |
| Symmetry | Very Good | Good | Good | Good |
| Culet | None | None | Pointed (none) | None |
| Girdle | Thin, Faceted | Thin-Med, Faceted | 0.6-3.4%, Faceted | Thin-Med, Faceted |
| Fluorescence | Very Slight Blue | Strong Blue | Very Strong Blue | Medium |
| Light Performace | ------N/A------ | ------N/A------ | 2 (out of 10 including 0 = 2/11 or "Excellent") | ------N/A------ |
| Proportions | ------N/A------ | ------N/A------ | 0 (out of 10 including 0 = 0/11 or "Ideal") | ------N/A------ |
| Finish Score | ------N/A------ | ------N/A------ | 1 (see polish/symmetry) | ------N/A------ |
| Brilliance | ------N/A------ | ------N/A------ | ------N/A------ | Very Good + |
| Contrast | ------N/A------ | ------N/A------ | ------N/A------ | Good + |
| Radiance | ------N/A------ | ------N/A------ | ------N/A------ | Very Good + |
| Overall Cut Grade | ------N/A------ | Very Good | AGS3 (Good) | Very Good |
| Light Return* | Very Good | Excellent | Excellent | Excellent |
| Fire* | Excellent | Excellent | Excellent | Excellent |
| Scintilation* | Excellent | Excellent | Excellent | Excellent |
| Spread* | Excellent | Excellent | Excellent | Excellent |
| Overall HCA Score* | Excellent (1.2) |
Excellent (0.7) | Excellent (0.8) | Excellent (0.6) |
EGL-International (Israel) Grading Report
GIA (Carlsbad, CA) Grading Report
AGS Grading Report
EGL-USA (New York) Grading Report
Additional Info
After speaking to a GIA rep I was told the symmetry was borderline Good-Very Good, and that I could send it in to be re-graded and possibly get a VG rating, but I declined and sent it to the next lab instead.
The EGL-USA report has some inaccuracies in the proportions grading, their graphic and numerics don't match up, and their measurements are off for the table. I was told this was due to formatting issues on their new reports (that I rushed them on since mine was the first one) and they are sending me another one with the corrections.
Overall Conclusions
1) This study was based on only one diamond. You can’t necessarily say GIA grades softer then EGL-USA or AGS based on this one data point. It does go to show you how subjective grading is especially with a stone like this one which seems to be borderline D-E in color. There is no D- or E+ with any of the diamond labs.
2) This study does reinforce something well known in the diamond industry which is that EGL-International graded diamonds are scrutinized more loosely then ones graded by the more reputable labs here in North America. It’s unfortunate EGL-USA gets a bad reputation based on EGL-International. This also means there are lots of good deals out there in the EGL-USA market if one is willing to pick through them to select the best stones. There are good deals to be had amongst EGL-Int’l graded diamonds as well but one has to be much more selective and have a jeweler they trust to work on their behalf or get the diamond independently graded. Anyone who tells you that all EGL diamonds should be avoided and won’t even spend the time to explain the difference between EGL-Int’l and EGL-USA is not being very honest with you. My approach has always been getting the best diamond for the customer regardless of who it was graded by. If your jeweler won't extend you the same courtesy they obviously have some hidden agenda or are just not eager to win your business.
3) Not everyone will want an AGS-000 super-ideal cut diamond. If there’s a 10-20% discount on a premium cut round vs. super-ideal and you can get 2 color grades higher instead like my fiancé decided to do with this diamond, there’s not necessarily anything wrong with that. I don’t ever recommend anyone get a poorly cut diamond, at the least please get a premium cut at a fair price. But just how premium a cut you decide to get is up to you and should be a matter of personal preference.
4) If you truly want an Ideal or Super-Ideal cut diamond, please stick with AGS graded diamonds. GIA has come a long way in trying to better establish a cut grade but they still leave a lot to be desired against AGS's standards. EGL-USA’s new 360 light performance grading report will definitely be a big plus to their organization and hopefully separate them from EGL-Int’l further but AGS still leads the pack with their cut grading and the EGL-USA 360 reports are currently not yet available to the public or trade.
PS – This article is titled “2007 Case Study” because I intend to do a similar study once a year every year. And as the case with this diamond, the selected stone will be announced, and all subsequent grading reports will be dated in the future as to prevent anyone from accusing me of being biased or selectively publishing results.
Kindest Regards, Yosef
Written by: Yosef Adde of Adylon.com, A division of Adde Enterprises, Inc., on 03/14/2007. All rights reserved.
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