Fancy Color Diamonds

Even mined diamonds may occur in various shades of yellow, pink, blue, green, or even red. These rare diamonds are referred to as fancy color diamonds and are evaluated by a set of color standards unique to them.

These standards take into consideration special factors, among them hue and color saturation. Fancy color diamonds occur when small amounts of certain minerals are present during the formation of the diamond, or when subtle changes in the crystal matrix arise as the diamond is being formed. Color is due to the absorption of particular wavelengths of visible light.

Yellow diamonds, one of the most popular of colors and orange diamonds, one of the rarest of colors, both owe their origin to nitrogen. This element is an impurity that replaces carbon in the formation of diamonds. The amount of nitrogen present in the diamond will determine the degree of absorption of visible light and thus the shade of color. The more nitrogen that is captured in the diamond, the more shade tends from yellow to orange. These same reasons give Gemesis laboratory-grown diamonds their distinctive color.

Blue diamonds, such as the Hope Diamond in Washington D.C.'s Smithsonian Institution, get their color from the element boron. Of the 10 highest per-carat prices paid for colored diamonds at auction, 6 have been for blue diamonds. They are extremely rare. Of all the South African rough production, there is on average only one significant blue mined per year.

Green diamonds are also extremely rare. At auction in 1992, a 1.28 carat green diamond sold for $250,000. The green color in a diamond is often limited to a very thin layer on the surface of the gem. If a green diamond is faceted and does not lose color it becomes a true rarity. The most famous green diamond is the 41 carat Dresden Green which actually was a hat ornament.

The color of a pink, reddish, and purple diamond colors are due to a variation in the diamond's crystalline structure. There is no trace ingredient in pink, but rather an irregular growth pattern at a sub-molecular level. The Argyle mine in Australia is the world's most important source of intensely colored natural pink diamonds. It produces 30 million carats of diamonds per year. Of that, less than 10,000 carats of rough are pink. Less than 1,000 carats are of a size over 1/5 of a carat. Buyers can expect to pay up to $1 million per carat for a mined stone of exceptional quality.

True red diamonds are the most rare and most expensive of all colors. Only about 20 stones have so far been certified as red diamonds. These gems have been priced at up to $1 million per carat. As with pink diamonds, red diamonds derive their color from a variation