Info on natural black blister pearl

Hello folks,

Now that the Eclectic Lapidary is up and running again, I can take
time to catch up on things.

I wonder if anyone here can help me with on natural
black blister pearls. I found an oyster shell with one on a
Chesapeake Bay beach. Oysters are a major industry here, so there are
shells just about everywhere. I’ve picked up a few small ones before
with little pearly blips (my description), but not fully formed
blister pearls.

Is this something common or unusual? Should I be on the lookout for

There’s an enlarged pic at:

Appreciate your help,

Carol J. Bova

Update: I realized I misspoke about the type of creature… it’s a
mussel, not an oyster.

I couldn’t find any concrete info online, so I contacted the Virginia
Institute of Marine Science today. Apparently, it is not common, and
it doesn’t seem to have been reported from this area before. One of
the researchers is going to look at more pictures that I sent
tonight, check around, and get back to me.

I’m sorry if anyone tried to check out the picture the other night

when our server was down. A fiber-optic cable was cut and we lost
service for almost 24 hours, but everything’s back to normal now.

Carol J. Bova
The Eclectic Lapidary