[Jewelry making - Article 00330] - [Orchid] Colored Stones

[charles b buckman]

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All,

    I was just wondering about colored stones.  Perhaps this topic has
    come up before. 

    There seems to be some colored stones out there where color is
    paramount.  Obviously this important with diamonds and such.  I know
    the good labs are equipped with spectrophotometers and colorimeters.
     L represent lightness level (0-100 units), a is red-green (+/- 50
    units), and b is yellow/blue (+/- 50 units).  Why don't they specify
    L,a,b color values for stones instead of guessing?  Some stones of
    value are totally opaque, like black opal.  Why don't they specify
    L,a,b of say 25.00, -3.4, 2.4 to quality as a black, and then have
    delta E units like +/- 5 units,10 units, and 10 units to be in
    specification?  You could have similar specifications for other
    materials like chrysoprase or lapis lazuli.  

    You could even use spectrophotometers to check clarity and
    transparency through light transmission.  You could check to see if
    the color of your chrysoprase ring has faded in sunlight, and by how
    much. 

    I mean we all spend up into the $thousands or more for these items. 
    Why not remove alot of the guesswork? 

Blaine Buckman 

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