I like the detail and the luster, but the coin has a green tint. I think your white balance is off. Go to photoshop and hit auto-color and see what happens. Here is your photo with the following adjustments: Brightness: +20 Contrast: +20 Saturation: +15 Auto Color The color still looks a little off to me. Are you mixing lighting sources by chance?
Well its funny you say that because on my monitor, it looks pretty good, but on my friend's laptop, the picture looks green. I don't think I'm mixing light sources unless two daylight bulbs with the blinds open is mixing light sources... maybe the sun is different than the full spectrum bulbs?
Make sure that you set your white balance on your camera to the appropriate setting every time before you take a photo. If not, the white balance will be off. Personally, I find that fluorescent bulbs work the best.
Those are fluorescent if I'm not mistaken. The white balance was set to the proper setting for the bulbs, but maybe the sun made it not work as well. I'll try tomorrow with the blinds closed.