Yo, Mike --
It looks like a guinea or half guinea dated 1790 from the UK. If it's genuine, it should be made of gold. My picture is of a genuine coin, and you can see that it does not match your coin exactly. Look especially at the inscriptions around the edges.
My guess is that you have a "spade guinea jeton," or a gaming piece used widely in Europe. Your jeton (aka "token") looks old, probably from the 1800s. Value is probably $5 US dollars or so.
Here is a detailed description of spade guinea jeton: