Nice photo. The diamond however shoud stand out more. Maybe a fill light or dodge/burn in postprocess? I also think perhaps you should have gone borderless or maybe a solid black or white border instead to compliment the elegant look?
I like your arrangement of the rings. I might try a more contrasting background, though. Since the metal of the rings reflect what they are laying on, they seem to almost disappear into the white.
Excellent focus. Looks like a magazine ad. Wonderful lighting. The shadows actually add to the power of this, not usually the case but I like them here. Nicely done.
I think overexposing 1 or 2 stops would have made the background really nice a white, rather than grey like this, putting more emphasis on the rings. Still, a very nice and sharp shot.