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 Post subject: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 12:44 am 
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Several years ago, I was given a diamond that had an EGL USA certificate. I know GIA is the authority for FCDs, but I did find the stone attractive and just thought to myself I will get it checked out further later. The color of origin per the EGL USA report was classified as natural in origin and the color grade that was given was "Natural Fancy Bluish Green". Some years later, I had the stone sent to GIA and it came back with the origin of color was "Undetermined". Do any of the experts here know how EGL USA determines origin for a fancy colored diamond compared to how GIA does? I'm curious as to how EGL USA came to find the stone was natural and GIA could not confirm it. Interestingly enough, with regards to color description, I don't agree with the color grade GIA gave this stone, and I rather agree with EGL's grading. I will try to take some better photos, but in the mean time I have some not so great ones for reference as well as each of the reports.

Any discussion, information, and enlightenment on this would be greatly appreciated!

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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 4:46 am 
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for determining origin of irradiated diamonds there will be both classical and Advanced gemological tests (Raman/Photoluminescence/FTIR/VIS/NIR...) and Multiple spectra will be recorded, many tests should be performed to avoid any false results due to distortion and smoothing.

maybe GIA had inconclusive results and because of that they categorized it as "Undetermined"

was stone mounted for EGL grading?

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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 9:01 am 
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Hi, the stone was graded loose both at EGL USA and at GIA. I will try to post images of the reports below.

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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 9:03 am 
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Here is a copy of the GIA report.

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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 9:07 am 
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Trying to post some extra photos, please excuse the fact that I'm new and trying to learn how to get stuff up here. The original photo above that was posted was the stone next to a D colored white diamond in white gold for reference.

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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 9:09 am 
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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 9:10 am 
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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Sat Jun 07, 2014 12:39 pm 
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Some green diamonds are very easy to spot treatments, some are more difficult and some are actually impossible to tell with certainity. I heard Thomas Hainschwang say the only green he would trust to be natural was one that has a long, known, history or one that could be traced all the way back to the mine. I guess he was not completely joking. Lots has happened since 2006, maybe GIA would judge differently now.

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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Mon Jun 09, 2014 11:25 am 
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EGL USA's fancy diamond knowledge and database is huge, many respected gemologists have been working for them during the past decade. However, both papers are quite old... resubmitting to GIA 8 years later could actually provide different results. Conny, methinks Thomas was talking only about green emitters, not all green stones in general.

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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Wed Jun 11, 2014 6:15 pm 
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A pretty stone anyway, with a very delicate colour.


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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Thu Jun 12, 2014 11:36 am 
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Thanks for the responses. It is a pretty stone, I just wish there was more info on how it is determined, etc. I do keep thinking that maybe I should send it back again to GIA, but I would like to feel more confident that the technology or methods have improved to be able to determine if it is natural or not before doing that. Only time will tell?


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 Post subject: Re: Green Diamond - EGL USA vs GIA
PostPosted: Fri Jun 13, 2014 10:23 am 
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Perhaps just calling their lab and asking the same questions you asked here would be a good idea.
It's a toll free number. :wink:
Tell us what they say.


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