Nice! I'm not crazy about the linoleum flooring (I guess you chose it so the refraction would be more evident?), but the gem and filigree are gorgeous. I think they should be sitting on velvet, and that the the velvet should be wrinkled and displaced by the weight of gem. Also, if you've got any caustics at play here, they're pretty subtle.
I agree as a scene I definetly need to do something different. I'll attempt the cloth suggestion, but doubt my skills are good enough to make it believeable. It would be a perfect setting though. I was thinking white satin in a white satin lined black jewelers box, you know the kind, with the hinged lid, there has to be a name for them.
Oh... sorry, on the caustics, I'm still working on that, I'm rendering with Sunflow, and still haven't got caustics figured out. Since this image, I did find you have to have IGI turned on with caustics, otherwise the object casts a solid black shadow.