[Jewelry making - Article 00495] - Re: [Orchid] Copal vs Amber

[Andrew Werby]

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>     Copal amber and Baltic amber are considered two different things
>     because they come from different plant sources (from different
>     areas of the world) and they have different degrees of
>     polymerization. 

    I'd agree with this if you didn't use the term "copal amber". Copal
    is one thing, amber is another. 

>     Andrew suggested that "Copal is at most some hundreds of years
>     old, as opposed to amber which is millions of years old."  This is
>     not really true.  Copal often is some 500,000 to 1,500,000 years
>     old or more. 

    Often? Have you got any authority for that? Did the person who told
    you that also want to sell you some? The experts I've heard opine on
    the subject tend to prefer a much lower age for copal. The earliest
    solidly dated copal deposits I've heard of are in Japan, and are
    ~33,000 years old.  But most copal is much younger (see:
    http://www.emporia.edu/earthsci/amber/copal.htm ) . The commonly
    available Colombian material we were originally discussing is at most
    1,000 years old and most of it more recent (see
    http://www.gplatt.demon.co.uk/typesof.htm ). Kauri gum, a New Zealand
    tree resin sometimes used for ornamental objects, is somewhat older;
    10,000 to 30,000 years.  But really, the absolute age isn't the issue
    as far as its usefulness is concerned. The properties of the material
    are dissimilar enough to make even the oldest copal quite different
    from the youngest amber. George Poinar, probably the worlds foremost
    expert on amber, draws a bright line at the 1.5 million year mark -
    anything younger than that isn't amber, period.  Here's another
    reference pointing out the differences:
    http://www.uky.edu/ArtsSciences/Geology/webdogs/amber/copal.html ] 

>     Both Copal and Baltic can exhibit a certain "gummy-ness" when
>     carved.  You have to be careful how much heat from friction that
>     you create if you choose to try power tools; it is possible to
>     discolor and/or burn the amber with too much heat.  Hand tools work
>     well. 

    Having worked with both, I've noticed a big difference. Yes, it's
    possible to create a heat-affected zone in amber, especially if you
    use power tools too enthusiastically, but it won't turn to goo like
    copal will. 

>     As a low cost material, Copal amber is a pretty altenative to the
>     much more expensive Baltic amber. 

    Maybe for a while. But due to its greater volatility, it has a much
    more pronounced tendency to craze in the presence of oxygen, heat and
    UV exposure, making it a poor choice for jewelry purposes. 

>     (Always remember to disclose that it is Copal amber to whomever
>     purchases your pieces; that keeps everyone happy.) 

    Don't tell them it's any kind of amber - unless you're the sort of
    person who sells graphite as "young diamond" ... 

Andrew Werby
www.unitedartworks.com

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