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Re: [Orchid] [4Sale] Chatham Emeralds
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Wayne Emery Tuesday, November 07, 2006
   
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    If you wish to pursue it, why not read the entire paragraph you
    chose to quote, which says the baddelyite crystallizes in the
    monoclinic system? 

    The VERY FIRST sentence of the chapter you quote from Lidicoat says
    "A synthetic gemstone is one that has the same chemical composition,
    CRYSTAL STRUCTURE," etc, etc. 

    Calcium stabilized cucbic zirconia incorporates the calcium into the
    atomic structure which forces this new compound to crystallize in
    the isometric (not monoclinic) system. So the crystal structure of
    the two is NOT the same. That is not a matter of semantics, it is a
    simple matter of chemistry. 

    As I attempted to point out, there is a gemological definition of
    synthetic and a trade or "Legal" definition of synthetic. Common
    usage, with entities like the TV jewelry channels flaunt the "rules"
    all the time." 

    But many legal cases have decided that CZ is a simulant and not a
    synthetic in the FTC sense. (And how it cold fit the gemological
    definition, given differing crystall systems, is beyond me). And
    Liddicoats usage of "synthetic" in relation to CZ has been discussed
    in probably every GIA class since the stuff was invented. 

    In the case of synthetic spinel there is a simple excess of aluminum
    oxide, but it does not force the symmetry of the growing crystal
    into a different symmetry class. And because of that, the crystal
    structure is the same, and the chemistry is essentially the same. 

    If you wish to believe that cubic zirconia fits the definition of
    "synthetic", then you are obliged to use the word "synthetic" before
    the term "CZ". At least for trade purposes. 

    You said " It doesn't help the gem dealer, jeweler or layman to
    understand these minute distinctions a bit. My opinion. I have a lot
    of those. ;-) " 

    Well, ask someone who is a member of the AGTA if it doesn't make a
    difference. It most certainly does. These "minute distinctions" make
    a great deal of difference in the gem trade. And extremely expensive
    courtroom decisions have hinged on these very "minute distinctions". 

    And I can assure you that my mineralogy professor of many years ago,
    quite correctly, would have put a big red X through any argument
    that tried to convince someone that compounds with differing crystal
    systems were somehow the same, and that one would qualify as a
    "synthetic" of the other. 

    It's not hair-splitting, Jerry, it's accuracy. Liddicoat's mis-usage
    of the term "synthetic" in his own writings (relative to CZ), based
    on classical definitions that he repeats from the world of
    mineralogy, has been a quiet joke for decades among gemologists and
    mineralogists who poke fun at their quasi-educated gemologist
    friends who are products of the GIA system. Anyone who has ever
    worked at GIA knows what a top-down centrist system it is, although
    much less so in the last 15 years or so. If Liddicoat wrote it, it
    was getting published. Anyone with the audacity to "correct" him
    would have been on the street quickly. Ergo, confusion among the
    students, taking a course designed specifically for those with no
    knowledge of chemistry, physics, mineralogy or optics. If you don't
    have to teach to a real knowledgeable group, you can get away with
    heinous errors. And if you're the boss, few will point out that you
    are wearing no clothes. 

    This original conversation centered, I believe, around the use of
    the term "synthetic imitation" or something like that, with which I
    have an issue. 

    Can we say that there are obvious synthetics, obvious
    imitations/simulants, and that a synthetic, like yellow/green spinel
    could be used as a simulant? 

    I think we can agree there. 

    I hope we meet some time and continue the debate, but I mean no
    slight or hypocrisy here and do not wish the tone to turn sour. Hope
    I have not offended you or anyone else, but minerals and gems have
    been the object of my education and love for well over 50 years now,
    and perhaps my classical education in mineralogy and geophysics
    appears to be hair-splitting to some. My only intent was to NOT
    mislead those whose education and knowledge lie elsewhere.

Wayne

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