In the world of white diamonds, any shade or tinge of color is not desirable. There's another group of diamonds that have vibrant hues called fancy color diamonds. Fancy color diamonds exist in a rainbow of yellow, red, pink, blue, green, purple and all shades in-between. Natural fancy color diamonds get their color in several ways. Color could be a result of radiation during the gems forming as with green diamonds. Trace elements in a diamond can cause color and in the instance of yellow diamonds, they get their color from nitrogen. Color can come from inclusions that can cause light to bend and show flashes of other colors.

Natural fancy color diamonds are rare and can be quite expensive. However, technology has found a way to manipulate less desirable diamonds to alter their color thus making man-made colored diamonds less expensive than natural diamonds. Irradiation and high heat combine to turn brownish or pale diamonds into richly colored, affordable diamonds. Diamond treatments are common and the color is stable. Always assume that any affordable fancy color diamond has been treated in some way. Ask for a lab certificate to verify authenticity of any fancy color diamond marked as natural.

When buying a fancy color diamond, color is the most important. The deeper the color the higher the value. If the color has an undertone or secondary color, does this enhance the color or take away from the color? This will also have an effect on the price. In fancy color diamonds inclusions are forgiven unless they make the gem unstable or so large it is very unattractive.

Yellow and pink diamonds are the most commonly sought after fancy color diamonds and this trend is likely to continue with celebrities like Jennifer Lopez and Kobe Bryant sporting fancy color diamonds. The most rare fancy color diamond is a certified red diamond. These are so rare most diamond dealers have never seen one. The red diamond is mined almost exclusively in Australia and South Africa.

A good tip to know, if you buy a lightly yellow to the eye diamond and mount it in a white setting - platinum or white gold - it will usually appear more colorless. Mounting the same diamond in a yellow metal usually enhances the diamond's yellowish tone.