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How can I know if the diamond matches the GIA cert?

Discussion in 'RockyTalky' started by hellotoall, Dec 14, 2001.

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  1. hellotoall
    Rough_Rock

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    by hellotoall » Dec 14, 2001
    There is a serious question:
    If an excellent cutter cuts thousands of diamonds a year.
    And get GIA certificate for each of them. However, when
    selling it, he sends out a diamond with a little better GIA
    certificate.

    For example, a H SI1 0.80 H&A diamond with a G VS2
    0.80 H&A diamond. Since only 1(or 2) grade lower, even
    an appraiser can't say it is misrepresented. How could a
    buyer know that if the diamond matches the certificate?

    The cutter can even put laser inscription of the GIA number
    of the better stone on this one, after he receive the GIA
    certificate.

    Thanks.
     
    


    


  2. pricescope
    Ideal_Rock

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    by pricescope » Dec 14, 2001
    There are several ways to verify the diamond matches its grading report. One of them is plot of inclusions. There are other proportions/factors that should match and exact weight and measurements of course.

    Too much troubles and too big risk. :-o People who are in this business know each other for generations.

    If you're concerned about authenticity of your stone bring it to professional gemologist/appraiser.
     
  3. oldminer
    Ideal_Rock
    Trade

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    by oldminer » Dec 15, 2001
    Leonid is telling you right info. Diamond dealers and cutters just don't come and go. It is a business that generations of family members particpate in. Not that I can tell you every last one has total integrity, but at the wholesale level, the diamond business remains a unique element of the business world nearly entirely operated on honesty, trust and a blessed handshake. Many diamond delaers believe their most prized possession is their "word" and their reputation. All else can so easily be lost or stolen, but integrity and honor can't easily be taken away unless one decides to ruin oneself.

    Mistakes can occur. I have seen it from time to time. Once in a great while their is some intentional act of fraud, but although I spend many hours a week doing the kind of verification you may need, I find very little necessity for the service. However, unless YOU know the business or the diamond, you may feel just like most people who come to people like me. You need to be assured by a professional who is acting on your behalf. It is nothing strange and should not be offensive to an honest dealer or retailer. They want you to be a pleased customer and not suspicious.
     
  4. hellotoall
    Rough_Rock

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    by hellotoall » Dec 15, 2001
    Thanks for the replies.
    Actually I bought a GIA certified F color H&A stone recently.
    Since I couldn't find an independent appraser in my area, I
    went to a local jeweler store for apprasal. The guy, who is
    a G.G., knowing that I bought the diamond from Internet,
    tried to convince me that I should be able to get a better deal
    from his store. After a while, he brought out a set of master
    stones(I think they are so called cz). He just opened the box
    and put my stone on it(a near white box). Then he put his
    F besides it. Apparently his is better. Then he put his G on
    it, still better! Then he put H on it... I have to say that I even
    think his H is even whiter(from my untrained eye!!!).
    However, he didn't say his H is better, but rather say they are
    even. So he said he would grade it as H instead of F.

    Being somewhat frustrated, I went to another stone, which I
    trust better somehow. The GG was busy. His wife, after
    knowing what happened, brought out her master stones.
    To my surprise, she has only 4, labelled as "F-G", "H-I"(or
    "H-J", I can't remember) and other 2. She brought me to
    a desk, under a special light, put my stone in the center and
    her 2 best ones on both sides. I have to say that my stone
    is not whiter than her H-I if not worse. However, she said my
    stone was between her 2 but close to her H-I. So she would
    grade it as G or H, but definitely not F. Then she asked if it
    has a cert and I told her it has a GIA cert. Then she backed
    off a little bit and said GIA is very good and maybe just grade
    half grade higher.

    Today I brought it to Rogers and compared it with the Hearts
    on Fires(the salesman was very nice). I can definitely say
    it is better than his H but definitely worse than his F. I
    compared it twice with 1 or his G stone. The first time I found
    they are very close, the second time I think mine is better.
    Of course, these are real stones, not master cz.

    However, I heard that GIA is restrict on the color and GIA's
    F should not worse than AGS's F, and should not be that
    close to AGS's G.

    My question is: what would be the correct way to grade
    the color with some master stone? Everytime we flip the
    stones with the culet up. Since H&A cut diamond try to
    eliminate light leakage from face, it may not look as great
    as others(like cz) from other sides, will this be the problem?

    What kind of light should we examine under?

    Thanks in advance.:angryfire:
     
    


    


  5. Garry H (Cut Nut)
    Super_Ideal_Rock
    Trade

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    by Garry H (Cut Nut) » Dec 15, 2001
    I think you need an "independant" adviser.
    Why not ship the stones to Dave?
    Otherwise ask the retailer to accept money and tell you if the stone you have matches the certificate clarity plot, dimensions etc.
    A third alternative is let the retailer have a chance to beat the price, and compare the color of the stone you have to the best he can do, face down in a paper under a fluoresceent tube lighting.
    BTW not all H&A's are cut to excellent proportions.
     
  6. oldminer
    Ideal_Rock
    Trade

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    by oldminer » Dec 16, 2001
    Most CZ sets of so called "Master Stones" and off from the moment of delivery. I check these sets for members of the trade and have only found 1 complet 10 stone set that was excatly right in several years of testing them. Now, that is my opinion, of course, and I am not the GIA. The GIA won't do this sort of re-grading of master CZ sets, so it is left to someone like me to do it. No choice. CZ's as master color grading tools must be used in a standard lighting. They are not good for use under travel conditions where lighting changes. CZ's are subject to fading. It happens overnite sometimes. We keep diamond master control stones in any CZ sets we use and check them daily for color changing whoich may be up or down. There is no pattern to it as each color is caused by trace impurities in the CZ material...

    Then you have the issue of asking a biased appraiser or a busy and biased appraiser for advise on a diamond bought elsewhere. It just won't be a reliable situation. Even if you get a truthful appraisal, how could you be certain?

    It is doubtful that the GIA report is off by two grades. In the opinion of some gemologists the GIA mmay be off 1 grade sometimes, but they are not the GIA and are only giving their personal "opinion". They can be wrong as having a GG diploma does not make every GG equal or that well qualified. A GG is a starting point, but there is a lot more to being a reliable diamond grader. You need good tools also. CZ master sets are tools, but not ideal ones. GIA or AGS/GIA DIAMOND master sets are the real tools needed. Even these don't make the user the GIA>>>> There are always issues that will be unresolved.

    If you really have doubts, you must use a well qualified and independent appraiser. Or, re-submit the stone to the GIA for confirmation.
     
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