I tried toning down the highlights in Photoshop using the "shadow/highlight" menu. Here's my result, which might not represent the coin in-hand.
In this case, the coin was too overexposed and details were lost. Here are a few thoughts on shooting coins that have worked for me:
• Make sure your light source is pointed at the coin, and away from the lens. Your photos lost their mid-tones, which might be due to excessive glare.
• Try diffusing your lighting source with white plastic or tissue paper to control highlights on silver coins.
• If your camera has picture quality settings, select a better option. Right now, the photo has too much compression noise to do any sharpening.
• Experiment with the exposure settings on your camera. Nikon Coolpix cameras are often contrasty. If there is a contrast setting, pick low-contrast for silver coins.
But I'm
hardly the expert on shooting coins- others here have written some great tutorials on the subject.

