Depends on the diamond. Colored diamonds that are Flawless or Internally Flawless and of a high carat weight (which in turn are expertly cut) are worth millions, and rightfully so. Most have inflated prices due to a monopoly creating artificial scarcity and rarely if ever deserve a fraction of what they're sold for. They are not worthless, but are an unwise investment. Gold on the other hand, is a wise investment. Genuine scarcity of gold dictates its market value, at least partially. Economics can in part influence its price as well for example. Precious stones such as rubies, sapphires and emeralds are far superior investments, because they are naturally scarce in high quality. Diamonds are really the product of a monopoly and tactical marketing. The processes of mining natural stones itself justifies at least some of their value, but not all of it. That said, the Blue Moon diamond is one of the most gorgeous stones I've ever seen.