Diamond Color

Pure diamond, if such a thing exists, is colorless. Most diamonds are slightly colored, even if the coloring is almost imperceptible. The commonest color is yellow which is caused by tiny amounts of nitrogen being present in the crystal structure, others are gray, light brown or greenish. Diamond can be almost any color, although strongly colored attractive specimens are very rare, and as such are not actively promoted by De Beers, probably in case consumers realize that blue, red, green and other colors are attractive, and start buying sapphires, rubies, emeralds and other gemstones instead of diamonds!As with many gemstones, colors can be artificially produced or modified. Some fancy colored diamonds are produced by irradiation and subsequent heat treatment. Natural fancy colored diamonds command very high prices, especially the more popular colors. Fancy colored diamonds where the color has been artificially produced are no less beautiful, but sell for more normal prices.We occasionally have fancy colored diamonds available in blue, green yellow, orange, pink, purple, brown and even black.
These lines have been taken from http://www.24carat.co.uk/diamondframe.html just for information purpose.