Fabio,

I had several thin walled unionids crack on me when I had them stored in
my basement. The swing in the relative humidity could be from 45-65%.

I have a few (collected after the ones that cracked) stored in zip-lock
bags and they have shown no visible signs of cracking. The numbers are
small and I did not control for variables such as temperature, size of
shell, or quality of the periostracum, however, it is an observation that
supports your hypothesis.

> I wonder if you keep a shell that is prone to cracking in a sealed ziplock
> bag or hermetic vial might help prevent shell or periostracum cracking
> because of minimized changes in humidity. I have not experimented with
> this,
> but I think it might help. Of course, sudden temperature changes are
> probably bad for any shell, especially fragile ones.

Regards,
Charlie
.................................................
Research Associate - Section of Mollusks
Carnegie Museum of Natural History
Pittsburgh, PA, USA

Assistant Professor - Family Medicine
Fellow-American Academy of Family Practice
Fellow-Academy of Wilderness Medicine

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