Diamond color can occur in nature as blue, green, black, translucent white, pink, violet, orange, purple, red, yellow, brown, or black. It is the unique impurities, or structural defects in a stone that yield colored diamonds. What occurs most often is that impurities replace a carbon atom in the crystal lattice, the structure of the diamond. The most common of these impurities is nitrogen, which yields a slight to intense yellow coloration depending upon the type and concentration of nitrogen present. "Black," or Carbonado diamonds are not really black. What your eye sees are many dark inclusions, close to one another, that make the gem appear black. Diamonds with a blue hue are a result of trace impurities of boron in the gem's crystal structure.

To give you an idea of the value of rare, colored diamonds, in October 2007 a blue diamond was sold at auction for almost eight million dollars.