Then it's probably a coin. Did the seller give you any clue? Was the coin in a box with other coins of some type?
Do you see any element of the design with the coin in hand? The size and weight remember to a Roman aes or Greek calcos, but with the design faded away it's impossible to know much more.
Referee for Spain, Iberia (ancient), Suebi Kingdom and Visigothic Kingdom
I bought from an elderly man who had not been able to identify it and had just put it in a box of mixed foreign coins. Nearly all of them were modern coins. Next time I see him I'll ask where he got it from.
The only form of design that I can see is in the second photo that looks like a man sitting looking to the right. Or may it is a cross? Apart from that I can't really distinguish anything else.
Might try this if you haven't. Wash with soap & water (only) & tooth brush. I have found that this uncovers a lot knowlegable marks.
You probably know this already so just trying to be helpful.