This is interesting -- a few years ago, Wired ran a piece about how two firms were trying to create gem-quality artificial diamonds for cheap(er). Well, it's a few years later (as always happens) and now one of those two firms, Gemesis, is selling artificial yellow diamonds at a 75% discount over the mined kind.
De Beers, one imagines, is not pleased. I mean, what's the fun in selling diamonds if you don't have to assassinate African heads of state to do it?
There's also the possibility of eventually making CPU cores out of diamond, is they can bring the price down enough. Diamond has such a high heat tolerance that much less cooling equipment would be necessary.