The story of "recycled diamonds" in America and how it might the hurt the global industry (as it is, high-quality rough diamonds have become more difficult to find, and more expensive to mine)is something that perhaps Yahoo doesn't want you to read about. As of now, Yahoo has removed the link to the story, and I could only get it via Google cache.
Main points from the "recycled diamond" story about the growing market for "used diamonds", when $1 billion worth of recycled diamonds might be put back into the market in 2012:
As more and more people are selling off their diamond jewelry, the industry worries that a flood of "recycled" diamonds may cause severe drops in the artificially inflated prices they sell their shiny rocks for.
The rough diamond market, before the stones are polished and cut, was worth about $15.2 billion in 2011, and could drop some 10 to 13 percent in 2012.
Up to $1 trillion worth of "used diamonds" are locked away in safe deposit boxes and jewelry cases, and many gems could find their way onto the market.