It looks like you were just off with the composition, but it's a clever idea. The lighting might work betterif it was facing the coin as well as opposed to the overhead lighting which makes the finger cast a shadow on the coin.
The contrast looks a bit flat. It looks like the fingers were over exposed but you tried to hide that by reducing brightness and contrast, but that just made the photo look dull.
Good idea. Could be improved just by holding the coin from the other side so that the shadow doesn't fall across the face. Maybe a lower ISO setting to reduce the graininess too.