Yeah, I am in that market as well but dropped off of eBay a long time ago. There are a couple of huge suppliers in Thailand and Vietnam who serve literally hundreds of different eBay sellers, so you get an endless stream of $1 NR auctions with which it is almost impossible to compete.
As far as a general dropshipper on stones and jewelery, you might have a look at alphaimports.com Their site is a nightmare to navigate but prices are not too bad, quality is as described (ie. they have good stuff marked as such, and not so good stuff marked as such, but it's all accurately marked) and their service is first rate. I generally care more about how a supplier deals with returns than whether or not everything is perfect, and AI has never given me any grief on a returned item, have in fact gone out of their way to make me happy on every order going back about two and a half years now.
I'm actually no longer active in that market -- if you are interested in some deeply-discounted one-time inventory from me shoot me a PM; I have app. 7600tcw of cut and uncut stones I've been pondering selling as a bulk parcel.