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Truth About Gemscan Stones


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Hi everyone,


Hoping I can get some advice on diamonds that I am looking at.  I am hoping someone can provide some clarity on Gemscan stones specifically.  I have read that they are often more lax on their grading standards and that their stones are not even certified to be diamonds.  Is there any truth to that?  


I am currently comparing a 1.5 carat / VS1 / F / Hearts&Arrows (Gemscan) with a 1.4 carat / VS2 / G / Ideal cut (GIA).  Through the loop, I can certainly tell that the Gemscan stone is cleaner.  And on a white background I can see the Gemscan be whiter as well.  The only difference is that I find the GIA actually has a bit better luster - just slightly when looking at it with naked eye.  Don't get me wrong, both are awesome stones.


My fear is investing a ton of money into something that is not what it claims to be.  


Look forward to the expertise in the room.




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Yes, Gemscan is not as strict on grading colour and clarity as some other labs are - however I very much doubt that they would call "diamond" something that is not. The laxity comes in the repeatability and reproducibility of the grading result (in simple words: what they call "F" today, tomorrow may well be called "D" or - less often - "G"; or, given two stones of the same colour, they may cal one "H" and the other one "K").


Incidentally, no gemmological lab "certifies" anything; GIA in particular are allergic to the word: all a lab does is provide an opinion on certain physical and chemical properties of a stone - this is the reason why "which lab" matters: there are no guarantees, recourse or globally agreed standards to fall back on; the reputation of the lab is your only guide to the quality of the report.


On the two stones - no way of telling which one is "better" from the info you have posted, never mind which one you like most, but GIA does not use the word "ideal" anywhere on their reports, so make sure the report actually IS a GIA report and not a report from "a GIA graduate".


You mention that one diamond has a better "lustre" than the other; lustre has a specific meaning in gemmology, and I very much doubt that two polished diamonds have significantly different lustre; can you try to describe what you saw? (And ideally provide some more data, particularly proportion and angle data from the reports?)


Final point: don't look at this as an investment from a financial point of view. It may well be the best "investment" you ever make from a personal point of view (that is: the decision to get married), but from a financial point of view look at the diamond as an expense. You are lucky that there is some retained value at all.

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Hey Davidelevi,


Thanks for the prompt response.  The GIA stone is 'triple excellent'...not ideal.  And it did have a laminated GIA cert, if that helps.  


As to the lustre comment, I was using it without knowing its link to gemology.  What i felt when comparing the stones was that the GIA one produced a slightly better 'sparkle' when comparing alongside the Gemscan stone.  Something about the intensity gave it a small edge.  Everything else (color, clarity and size) I could see the Gemscan was better.  But with that in mind, the Gemscan was about $1k more expensive.  


I don't have the details on me, but I know i could get more info on the GIA.  The Gemscan only came with the 'precert' so it only showed the 4 Cs qualities.  


My biggest concern is that the Gemscans apparently do not say 'diamond' anywhere.  So is there fear that it may not be one?  Also, if I pay for a complete Gemscan cert, would it have all the same details as the GIA?  



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The biggest concern I would have is that the diamond has been somehow treated, not that it isn't diamond. Even that, I would say is minor. On the other hand, the unreliability on colour and clarity may have a significant effect on fair price, and it is much more common.


The most detailed Gemscan reports have most but not all of the info on a GIA report, and what is most important is that they use a significantly different way of grading cut (in addition to the colour/clarity issue we have discussed above).


One good foundation article on cut - so that you can compare more easily and understand better what you see when looking at diamonds: http://diamondcut.gia.edu/pdf/cut_fall2004.pdf

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If that is the case, what is the best method in validating whether or not I am paying a 'fair' price on a stone that has been certified by Gemscan?  


Having compared the two up close, i can tell the Gemscan stone is better in color and clarity.  But its truly the cut that I cannot figure out, since it shimmers better - and i suppose this speaks to not knowing how a cut is graded.  

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Get a competent, independent appraiser to help you. I think there are a few threads on the forum about this topic, but to summarise:


1) The appraiser is not independent if it is a competitor (choose someone that does not sell jewels but makes his/her living purely from appraising)


2) The appraiser doesn't work for you if you are not paying his/her fees.


3) The appraiser is less likely to be independent if he/she has been recommended by the seller. This varies from "You could try X, Y and Z; they have a good reputation and I respect their expertise" to "I will only let the stone go to X, Y or Z because of A, B or C reason".

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  • 3 weeks later...

Have you thought about sending both stones to AGS for evaluation.  Yes, it may cost a few hundred bucks to have them evaluated and obtain AGS certification, but I think it would be money well spent and a great way to have all of your questions answered!

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