[Jewelry making - Article 00390] - Re: [Orchid] Changing the term "semi-precious" stones

[Peter W . Rowe]

========[ Invite a Friend - http://www.ganoksin.com/invite.htm  ]========

>     Chances for the perfect emerald are not that extreme, so GIA
>     position is kind of hard to understand. 

    First, Gems and Gemmology is indeed a fine place for Gemmological
    research to be published. In fact, since it's the major trade
    publication on the subject of gemmology, it's the most logical.
    There is no specific set of regulations about what any scientific
    publication can, or cannot, either publish or establish as it's
    editorial policy. The marketplace itself will establish the
    reputation of the publication. It's not set in stone. In general,
    rules of science (which, while generally accepted, are not
    unchangeable) are respected, and papers accepted for publication
    will be subject to at least some peer review. That's about it. Some
    scientific publications do better at this than others. Just because
    quantum physics says that some things, no matter how improbable, are
    indeed potentially possible, has no bearing at all on whether a
    colored stone grading system developed by GIA should have to equally
    establish seperate grades for every extreme potential. For one
    thing, Gems and Gemology is the magazine, which is one
    function/entity/activity of GIA. The colored stone grading system is
    not beholden to Gems and Gemology. It was developed by GIA, but for
    it's educational program, and in hopes of it's being of use to the
    industry. Although Gems and Gemology may publish papers describing
    that system, there's absolutely no reason why the nature of the
    magazine should somehow dictate the nature of the grading system.
    There's no connection between the two, other than the parent
    organization. The grading system was not devised as an attempt to be
    able to describe all possible minute differences in grade of all
    possible stones. In fact, the myriad possibilities of such a system
    is one reason why such grading systems have not generally caught on
    in the past. To be commercially viable and usable for most people,
    the system had to be simplified enough so normal human users could
    make use of the system. Lots of compromises there were needed, but
    the goal of such a system is to make it useful in the real world, for
    people working with the vast majority of the gems available. To
    suggest that the colored stone system is lacking and remiss because
    the Gems and Gemology publication, which has no relationship to the
    reasons the goals and nature of the grading system were established,
    is itself a publication which might be suited to the presentation of
    research that describes a more exactingly minute and detail oriented
    bit of gemmology, is just bizzare. Sometimes, Leonid, you leave me
    just plain scratching my head in puzzlement at how you arrive at
    these relationships. You have, obviously, a vast body of experience
    in jewelry making and expertise in this field. But I'd have to
    hazard a guess that it's been a while since you studied the nature of
    logic, and what does or does not constitute a valid conclusion to a
    given set of facts... 

    I'll say it again. The GIA colored stone system is intended to give
    a useful general means by which the grades and qualities of the vast
    majority of gems can be meaningfully described. It needs to do this
    in a language that is simple enough so as to not be too cumbersome,
    in order that the greatest number of situations can adequately be
    described. But to do that, some extremes and highly unusual
    situations simply won't fit. This itself is not a problem with the
    system. There is nothing, for example, that prevents an appraiser or
    gem grader from appending a comment of some sort to a GIA colored
    stone grade. In this case, if the grader feels that a given emerald
    is substantially better than the normally assigned top grade might
    suggest, he or she can simply indicate this in the comment section.
    Stones in this catagory most likely cannot be evaluated solely on the
    basis of a GIA grade anyway. At this point, it will take a human eye,
    with experience in valueing emeralds, to really know the full finest
    degrees of quality. The GIA grades simply don't divide down fine
    enough. 

    This is, by the way, not limited to the colored stone system. Look
    at the well loved (or hated) diamond grading system. How good is an
    I-1 stone anyway? Some are not so desireable, others seem to get
    called SI3 by people who feel the GIA grade is too broad and need to
    invent their own. Within each grade, there's a good deal of variance.
    Yet for most purposes, it's close enough. You don't need grading
    systems to seperate or describe differences out to millions of minute
    differences, even if in some ways, with modern science and
    technology, the grades could be divided up a good deal (color
    grading, via optical measuring devices, for example, can be much more
    precise than the plain old GIA grades.) 

    And at the other end of the scale, there's a vast range of gem
    materials that the GIA system simply doesn't attempt to grade at all,
    since they're too low in clarity of quality. The lowest clarity grade
    gets simply called declasse (nice french for unclassified. why they
    used a french word is anyone's guess.) That catagory will range from
    stuff that does have decent uses, perhaps as a cabochon or carving
    material, to stuff that's fit for driveway gravel or aquarium rock.
    You don't seem upset that the system ignores these gradations. But
    it's reasonable for it to do so, simply because the gem marketplace
    doesn't want or need grading reports for this type of stuff. 

    It's not about quantium physics, Leonid. Or whether a given magazine
    publishes serious research papers. It's simply about a tool developed
    to teach colored stone grading, and intended as well to be a useful
    and usable tool within the trade. 

    One other comparison as to why too much detail might not be so good.
    Do you happen to remember Cap Beesleys attempt, via AGL, to come up
    with a color grading system? They developed and sold a rather costly
    set of color grading cards (which must have been a bitch to make
    since they never actually finished publishing all the planned cards).
    emeralds had something like a half dozen cards, with extremely fine
    graduations in color. Much more exacting, I thought, than the GIA
    system. So exacting, in fact, as to be almost unusable to anyone
    other than another owner of a set of those cards, and even then, a
    bit incomprehensible. You needed the cards, then sets of charts to
    determine what some grade number meant in terms of quality.
    Cumbersome. The GIA system is designed so that, although grading
    tools like the gemset sample set can be useful, it can actually be
    used just by people with a good loupe and decent eyesight, just as
    the diamond grading system can be. The terms and nomenclature make
    decent sense once you learn them, and are reasonably consistent.
    Does it do everything? Hell no. Does it do most of it? Sure. And the
    result is that people use it. I don't know too many graders or
    appraisers now who even remember the AGS colorscan cards, and if I
    were to ask a gem dealer for an emerald that matched card number
    such-and-such, I'd most likely be out of luck. 

Peter
____________________________________________________________________
T h e   O r c h i d   L i s t
Open Electronic Forum for Jewelry Manufacturing Methods and Procedures
____________________________________________________________________
Orchid FAQ:
~ http://www.ganoksin.com/orchid/faq.htm
Orchid Archives:
~ http://www.ganoksin.com/orchid/archive
Orchid Galleries:
~ http://www.ganoksin.com/orchid/gallery.htm
Invite a Friend:
~ http://www.ganoksin.com/invite.htm
____________________________________________________________________
Tips From The Jeweler's Bench - Article Archive
~ http://www.ganoksin.com/borisat/tip_sear.htm
The Jeweler's Selected Bibliography List
~ http://www.ganoksin.com/jewelry-books
Buy Orchid Jewelry:
~ http://www.ganoksin.com/shop
____________________________________________________________________
-Unsubscribe:
-Email: orchid-request AT ganoksin.com Body=unsubscribe subject=blank
____________________________________________________________________