In hope this helps. The calm the pearl was found in was wild caught, Houston Texas. The restaurant said the purchase thee clams from sysco foods. The pearl doesn't appear to be soft. I almost broken a tooth when I bite down on the clam.
A broken tooth was my first thought as I had a similar experience many years ago. (My clam pearl is purple and tiny but still gave the teeth a jar.) This one looks like a pendant in the making