A couple companies create diamonds through the application of pressure and heat to carbon. They can create diamonds just as good as those dug from the earth and are 30% cheaper. Here's a link to a story about them: http://pubs.acs.org/cen/coverstory/8205/8205diamonds.html

I mentioned this all to my gf and she replied "What is that, cubic zirconia? I don't want an imitation. A real diamond is from the earth".

I think man-made diamonds could destablize the whole diamond mining industry but as long as my gf's viewpoint is prevalent (which I believe it is), man-made diamonds won't be a viable option to most consumers.