And if you have... did you return it?

I've never found anything valuable but my aunt did! Growing up we had a family beach house on the Jersey Shore and any time there was a big storm the beach would be covered with seaweed that washed up from the ocean. We would walk along the beach and look to see if anything cool washed up. One year my aunt found a diamond ring!! There was no chance of finding the owner since it was likely lost years ago and who knows where it drifted from, so she still has it!