Legal tender is generally not invalidated unless destroyed. Stealing property does not grant you legal possession over it, so you'd be hard pressed to find anyone willing to accept that coin in exchange for anything since they could easily determine that you have no right to exchange it in the first place.

The most you could do is destroy it, the end result would be as if nothing happened and that's about it.

There's a market for stolen art; surely you could find a buyer for the coin. You'd get nothing near the face value though.

Pretty sure at that point a wormhole opens up at the center of the U.S. Constitution being held in the National Archive