A large clam fossil. Not sure how old, but beautiful.
I am lucky to have 3 pieces of furniture from the late 1700’s. I have never seen anything like them before or since. I almost passed up on one of them. My wife really wanted it. After a restorer used his “magic dust” to clean the wood and expose the beautiful inlay; I was glad my wife pushed for it.
Can you post a few photos of it? Maybe we can figure out what it is and how old.