At http://www.mailbase.ac.uk/lists/sea-site/1999-03/0031.html, Barry Kaye
wrote,
"Calcium carbonate is susceptible to 'Bynes disease' or 'Efflorescence X' -
basically, if stored in wooden cupboards or on wooden shelves in
unventillated stores, acetic or formic acid from the wood result in the
formation of hydrated calcium formates or acetates (the actual formula is a
bit more complicated). These new minerals appear as a white 'fluff' on the
surface of the ceramic (problem is very common with natural history
collections of shells, and results in white blotches, and damage to the
surface of the shell)."

Interesting. I'd like to hear more. Are bacteria involved? What can be done
about it?

Andrew K. Rindsberg
Geological Survey of Alabama