To my untrained eye, it looks like a forged coin, made to look somewhat ancient. I even think it's trying to be ancient Hebrew. (Some of the letters look similar.) Thing is, the coins from that era are generally in much worse shape. But here is roughly what a "new" fake one looks like...

https://www.judaicawebstore.com/half-shekel-coin-stand-silver-replica-P10167.aspx

Here is a real one from the time of Dovid HaMelech/King David.

http://www.nbcnews.com/id/45419597/ns/technology_and_science-science/t/coin-discovery-sheds-new-light-sacred-jerusalem-site/

Either way though, it's a neat find!