For those interested in pearls there is a review article in Aquaculture
magazine about the current state of pearl culture in the world today.  It
seems the Chinese have flooded the market for cultured freshwater pearls
and drive the price to about $5 US (wholesale) for a 12 in (30 cm) strand.
A 22 mm nucleus was produced in India out of a Turban shell, which may be a
suitable substitute for freshwater mussel nuceli (good for unionids bad for
turban shells).  The south seas pearl industry is using nuclei made from
"mother-of-pearl shell" (I have no idea what species this is).  Also noted:
the most valuable pearls were the pink pearls produced from conch shells
($5000 US for a 5 mm pearl); Mexico is developing pearl culture in the
Pacific using Pteria sterna and Pinctata mazatlanica (the latter is not in
the compendium); there is significant predation on the pearl oysters used
in the Hawaiian and Marshall Islands by Cymatium, trigger fish, and wrasse.
CItation for the atricle is:  O'Sullivan, D.  1999.  Global importance of
pearls increases.  Aquaculture Magazine  25(2):28-32.
 
If anyone has any "pearl shells" they are willing to part with, I could
really use a few to put in a traveling display I take with me when giving
talks on mussels, etc.
 
 
Kevin S. Cummings
Illinois Natural History Survey
607 E. Peabody Drive
Champaign, IL 61820
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http://www.inhs.uiuc.edu/cbd/collections/mollusk.html