Use a Rubbermaid plastic container
I saw a technique once that used a translucent plastic storage tub. They turned it on its side, and taped a black backdrop to the back and draped it down the the front. Put the item inside, and put a bright desk lamp over the top…you can use multiple lights. The translucent plastic diffuses the light nicely.
Your digital camera should adjust for the lighting source…if not you can use PhotoShop to adjust the photo “filter.”
Also, on jewelry, I find that if I’m too close to the item I can’t get my camera to focus. Get a little further back and zoom in on it (not too much…if you go too far your camera does some “interpolation” and the picture is grainy.
And when you’re done, you can use the tub to store your photographic stuff!