Showed some people the scans, and no one thinks it's a coin - even an ancient one.
Ancient Greek/Roman/whatever coinage had crude designs, but they had a picture and more extensive lettering.
One person suggested that it might be something used to seal letters (when they imprinted hot wax with a seal) but I think the lettering would be backwards if that were true - so you could read it forward when impressed in the wax.
Good luck finding out what it really is.