It may surprise some people to learn that diamonds have color since many people know diamonds only as cut gemstones that are as clear as optical glass. But the truth is that the bulk of the diamonds on sale have a tinge of color ranging from the barest hint of a color to a strong hue. Like diamond cutting, determining the color of a diamond is a precise process and it affects the value of the stone.
Color in diamonds comes from chemical impurities in the stone and imperfections in its molecular structure. The variety of impurities that can be found is large enough to give the stone a potential array of colors, the predominant ones being yellow and brown.
This color is considered normal and does not mark a stone as immediately inferior to another. Diamonds with the most intense colors are referred to as "fancy color" diamonds and have names like cognac or champagne diamonds. In fact, the ones with the most extreme amount of color are rarer than those that are absolutely clear. A canary yellow diamond, for example, is a more prized possession for some people - and more expensive - than a comparably-sized clear diamond because it is rarer.
This does not mean that diamonds that are absolutely free of impurities and imperfections are commonplace. Quite the opposite. Crystal-clear diamonds are valuable and sought-after because of their rarity as well as their beauty. The stones between these two extremes are graded on the scale shown here.
D-F Absolutely colorless. This is the highest color grade and quite rare.
G-J Near to colorless. These may appear colorless when mounted in white gold or platinum.
K-M Diamonds in this category have a visible yellow or brownish tinge. These diamonds are not generally recommended for engagement rings and where large-sized stones are appropriate.