The planet’s most valued gems are fancy color diamonds. Only 1 in 10,000 diamonds has a fancy color and they come in almost any color you can imagine. Red, green, purple, orange, pink and blue diamonds are the rarest. Yellows and browns are the most common fancy colors and they’re generally less valuable than other colors. Gem diamonds in GIA’s D-to-Z range usually decrease in value as the color becomes more obvious. Just the opposite happens with fancy color diamonds: Their value generally increases with the strength and purity of the color. Large, vivid fancy color diamonds are extremely rare and very valuable. Yellow diamonds currently possess the highest market demand of all other colored diamonds in the market.