I'd like to see a normal clear photo, I am certain it is a nice coin, but all of these photos are washed out.
I don't know what to do. The coin is very bright and shiny with clear fields. Less light will make it look black.
Try different shots. Some in natural light. Some outside. Some inside near the window. Some inside with room light. Some with the flash on, some with the flash off. Different rooms have different types and amounts of light.
Yes. Try a black background. Also white can work (copy paper) and yellow, Manila envelope. Coins and jewelry are VERY difficult to photograph properly (unless you are a professional with all the right equipment.) In our old house, for whatever reason I was always able to get good shots of coins, and in the new house it is very difficult, and frustrating.