Jim Miller asked about spots that are "bright white and seem to actually be
under the glossy surfaces around the aperture. There are no breaks in the
surface that I can see with a hand lens."

Lord knows I am not an expert on this, but could these spots be an example
of Byne's disease? To recap previous threads, Byne's disease is
deterioration caused by the shell being housed in a wooden cabinet with
little air circulation in a humid climate. Some woods, such as oak, react
with humid air to emit acetic and formic acids. You can recognize these
woods by their sharp, sour (acid) smell. If the cabinets are tightly
closed, then the acids build up in the air and react with the calcium
carbonate of the shell. Acid paper and cardboard can have the same effect,
which generally takes a long time to be noticed. The spots are whitish and
fluffy, consisting of calcium acetate and formate. The underlying shell
becomes porous. Some families, species, or even individual shells are more
susceptible than others, so one shell can be harmed while the one next to
it is not. Cones and cowries are particularly susceptible. Damage is
irreversible. To prevent Byne's disease (which obviously is not really a
disease and is not contagious), you can:

1. Reduce the local humidity (e.g., with a dehumidifier).
2. Increase the local air circulation (e.g., open the cabinets
periodically).
3. Seal off the wood by painting or lacquering the interiors of the
cabinets.
4. Replace wooden cabinets with metal ones.
5. Replace acidic paper and cardboard with materials of archival quality.
Remove all newspaper, which is very acidic.

Byne's disease is not the only problem that can be encountered in shell
collections. Previous messages, particularly from shell dealers such as
Paul Monfils and Guido Poppe, tell of problems with living insects, ticks,
and fungi; improper cleaning; and improper preservatives or other chemicals
placed on shells.

Andrew K. Rindsberg
Geological Survey of Alabama