[Jewelry making - Article 01025] - Re: [Orchid] Zachariah turquoise treatments

[The Doctor]

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    Steve, I believe the process referred to here is the Zachery
    treatment. It appeared in the late 1980s, and has been used to treat
    millions of carats of turquoise since then. The details of the
    treatment are pretty much a mystery, but gems that emerge from it
    have better color, less porosity and take a better polish. So far,
    it has proven to be a stable enhancement that may reduce the stone's
    ability to absorb body oils. I would imagine that, since the process
    takes three to six weeks to accomplish, it ain't cheap, either.
    Also, while the claim is that there is no polymer impregnation,
    there is no available information about resins, dyes or other
    components. The salesman overstepped what little is known about the
    process. Nobody really knows. 

    The only clue I know of so far comes from GIA. Using sophisticated
    testing equipment, they have discovered that most Zachery-treated
    turquoise contains a lot more potassium than untreated material, but
    that doesn't help those of us who don't have a SIMS unit. 

    There are some subtle characteristics of this treatment. Sometimes,
    a Zachery-treated turquoise has dark blue color concentrations in
    and around it's fractures. Occasionally, the "robin's egg blue"
    color can look somewhat unnatural. 

    It's difficult for a trained gemologist to detect this treatment,
    and even a world-class gem lab can miss it. This type of treatment
    situation always begs the question: If it is stable and
    undetectable, is it worth doing? My answer is usually: If it is used
    to make inferior material into gem material, and (this is the
    important part), if it is disclosed to the buyer, yes. Enhancing and
    improving gem materials is a part of the industry that can help
    preserve gems that would otherwise be crumbly specimens, not that
    there is anything wrong with specimens. There is only so much fine
    gem material to go around. 

James in SoFl

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