There is no natural shortage of diamonds. Diamonds can be manufactured at much lower cost than the corresponding natural diamond price and the chemical and structural purity of a synthetic diamond can exceed a natural one. Diamonds are a difficult investment. While it is easy to buy a diamond, it is not easy to sell one unless one is already an established diamond merchant. Another problem for investors is that purchasers other than established jewelers will be paying retail for a stone but can get only wholesale at most if they sell it back to a jeweler. Some firms offer "investment-grade" diamonds for sale to the public. A careful investor should ask for a written promise to rebuy the diamonds at or near the purchase price within a specified period.
Today there are little funds that are investing in diamonds. These funds purchase unique diamonds (very large in size or color), each stone is checked by a few professionals and negotiated awaiting the fund decides to purchase it. Between 2007 and 2008 the price of a diamond from the top range of color, clarity, cut and carat went up by over 50%.