It depends on the quality of the paper. Cheap cardboard is often rather acidic and a cause of severe Byne's disease over the years. I can confirm that old gelcaps get brittle and opaque over time.
Sulfur compounds in fossils can be a serious source of acid as well. Pyrite molds and casts are especially a problem, but other minerals may also be present in some cases.
---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------"I have seen specimens stored in glass vials in old collections that were severely affected by Byne's disease, but I cannot tell whether the main culprit was the glass, the stopper or the paper."
Dear Paolo,
the main culprit often is neither of these, but salt residues in the shell. Thorough rinsing in fresh water remains essential.
Cheers,
Marien
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Dr. David Campbell
Associate Professor, Geology
Department of Natural Sciences
Box 7270
Gardner-Webb University
Boiling Springs NC 28017