Pearl in a smoked oyster?

by Derek
(Duluth, Mn)

I bought some Geisha smoked oysters yesterday from a local grocery store. I put one in my mouth, which looked a little bigger than the rest with more of a "tail". I bit down and almost cracked my tooth on something. I spit it all out, and this is what I found. I just would like to know, if possible to tell from the photo, that this is a pearl and not just a rock. Is this possible? Thank you.