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Are GSI reputable and reliable certifications?


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I just received a 1.25 carat diamond that is rated by GSI (Gemological Science International) as Color I, Clarity SI2, Policy and cut as very good.  I am not convinced that we got value for our dollar.  It feels like my husband fell for their "retail price is $15k, your price is $10k" and stopped looking from there.  I question whether any jeweler would take a 30% hit right off the top but when I price out similar rings online, $10k is still high.  Granted little overhead with places like Blue Nile, but still.  I am really interested in hearing feedback regarding GSI and it's value.


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No matter who graded the stone, if you’re worried about the reliability of the grading, have it checked out by your own expert.  Where are you and I’ll try and send you a referral?  Most are not expensive and there is far more important information than appears on the lab documents.  Remember, it's not a second opinion if it comes from the same source as the first. 

To answer your question.

GSI is a large operation that provides sales documents to a wide range of dealers.  They’re popular with the chain and department stores.  Do with that information as you wish.

You’re right to be nervous about claimed discounts as well as the grading details.  Those are among the questions to ask in the above appraisal session with YOUR expert.

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Couple of threads about GSI from this forum:

The threads are old, but the fundamental issue hasn't changed: anyone can set up a gemological lab, and GSI's grades are not particularly reliable. The price difference between SI2 and I1 is usually large, and with lower clarity stones there is a huge variability in "fair price" within the grade: stones with easily visible inclusions will be discounted far below the grade average, and those with nearly invisible ones will go for a premium.

You mention a ring - which further adds to the uncertainty on price: a simple setting may be worth $300, but it's perfectly possible to spend several thousands even with a plain solitaire setting.

GIA I/SI2 retailed online top out at about $7,200 (except outliers):


$10k (plus taxes?) sounds like a high price - though if the setting is of high quality, the stone is fairly graded and the jeweller is a "full service" outlet it may still be reasonable vs. internet prices. That's a lot of "ifs".

Edited by davidelevi
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$10k is on the high end but a far bigger issue is the grading accuracy. The difference between a GIA 1.25/I/SI2 and an otherwise similar 1.25/J/I1 is nearly a factor of 2 no matter where you buy it.  It's even more if we include things like cutting and fluorescence. These are not tiny details. 

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Thanks so much!  It's a simple cathedral setting in white gold.  And a thin setting at that.  Based on comparable settings I am seeing on line, it can't retail for more than $700.  I am definitely not feeling this was a decent buy, let alone a good buy. 

Full grading is

Shape/Cut: Round Brilliant

Weight: 1.25

Color Grade: I

Clarity Grade: SI2

Policy/Symmetry: Very Good

Cut Grade: Very good

Treatment: None

Measurements on the stone are 6.67 - 6.59 x 4.35.  This is a rather deep stone from what I can find online.  I think it's going back.


Edited by Heather9911
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