I'm with @coloradobryan. Voting fake but waiting for the experts. How did you acquire it? How much did it cost? Those can be valuable clues as well. Edit: do a quick Google on it and you'll see that, if it is real, it is a very valuable coin. Sorry, but that's strike #1 and a good sign that it is a cast fake (it looks cast to me) ;-) (the fact that it is a valuable coin and "worthy" of counterfeiting)
It looks like a modern cast reproduction. These are pretty common. Look at the edge for the casting seam.