I mentioned this once before, but if you bought any diamond jewelry between January 1, 1994 and March 31, 2006, you are probably eligible to receive part of a class action settlement against DeBeers.
Go here Diamond Class Action for all of the relevant information. You do not have to submit a copy of your receipt if your purchase was under $10,000. I just submitted my claims online and it took less than five minutes to do. If you do have your receipt or appraisal it is much easier, since you do need to know your purchase price. Fortunately for me, we bought the rings during a much more organized part of my life, so I had a file folder neatly labeled "Rings" that had copies of receipts and appraisals. Oh, how I wish I were this organized these days.
It appears that you could get back a significant amount of money, the deadline is May 19, so get it submitted now!