[Jewelry making - Article 00200] - Re: [Orchid] Holly Blue Agate Vs Chalcedony?

[doug]

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Hi Noel,

>     To our stone gurus-- What is the difference between holly blue
>     agate and chalcedony?

    Glad to lend a hand! Blue Chalcedony is, as it's name infers, any
    chalcedony (cryptocrystalline quartz) which is bluish in color --
    whether it is from the original Calcedon site in Turkey, or not. In
    order to wear the noble title of "Blue" chalcedony, the material
    apparently only has to bear an infinitesimally slight bliush cast, if
    the samples I once received from the original Turkish site are any
    indication; most of it was rainy-day grey with only 3-5% blue in it. 

    Holley Blue Chalcedony, on the other hand, is actually a lilac to
    rich purple (amethystine) chalcedony, typified by thin, horizontal
    vugs of colorless microcrystalline druzes or cryptocrystalline
    quartz, surrounded by 1-5mm thick layers of white chalcedony,
    followed by various shades of lilac, lavender or purple chalcedony.
    In thin cross sections, a good deal of this material looks like a
    rather sleepy Rose de France amethyst -- or, if you'd prefer, a
    hybrid of that amethyst and the milkier grades of Brasilian Rose
    Quartz -- but with a cross section more like a diffuse Crazy Lace
    Agate. Holley Blue came only from one site near Lebanon, Oregon -- an
    area which has since been subsumed under the aegis of the BLM, so
    future mining is unlikely. Although I can't swear by it with 100%
    certainty, one report I'd heard, years back, explained that the
    material was originally named "blue" because of the decidedly bluish
    cast that some of the surface "float" material had when it was first
    discovered, back in either the late 1960's or early '70's. (Since the
    reddish or pinkish components of both rose quartz and some varieties
    of amethyst, as well as the topazes from both Colorado and Guerrero,
    Mexico, are easily bleached out by prolonged exposure to sunlight, it
    seems at least remotely possible that this explanation carries some
    veracity. Perhaps there are some "older timers" out there with either
    firsthand experience or more familiarity with the stuff? Whether or
    not that's so, I hope my insights've been helpful to you, Noel! 

    Best regards to you and "Bob", 

Douglas Turet, G.J.,
Turet Design, LLC
P.O. Box 242
Avon, MA 02322-0242
Tel: (508) 586-5690
Fax: (508) 586-5677
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