Brown, Gray and Black Diamonds
The discovery of diamonds in 1979 at the Argyle Mine in northwestern Australia changed the market for fancy color diamonds. Nearly 50% of the production from the Argyle Mine entails stones in some shade or hue of brown. These different shades of brown have been marketed as "champagne," "cognac," or "chocolate." Brown diamonds form when nitrogen is present in the diamonds' crystal lattice or when there is significant distortion to that crystal lattice. Some of the largest diamonds in existence include notable brown diamonds, like the gargantuan champagne-colored 545.65-carat "Golden Jubilee" cushion-shape diamond, the largest faceted diamond in the world, and the triangular-shape flawless brown, "Incomparable," at 407.88 carats.

Fashion loves brown, gray and black diamonds. Black and white design combinations are featured in many contemporary jewelry pieces. Black diamonds lend a special sparkle that contrasts well with colorless diamonds and other neutral colors, such as white, light brown, and light yellow, and provides a welcome change to the palette of accent stones. Brown color diamonds are particularly effective contrasting with orange- or pink-colored stones and set into pink gold. Natural color black and gray diamonds contain highly particulate and diffuse inclusions, which can color them densely enough to appear black, but which might actually be deeply brown or green. Most of the black diamonds used in jewelry today are color enhanced because the polycrystalline mass that forms most black diamonds makes them extremely hard to cut. A famous black diamond is the cushion-shape 67.50 carats known as the "Black Orlov."

Yellow Diamonds
Yellow diamonds are the most common of the fancy color diamonds and are probably the best known by the public. Nitrogen is responsible for the color, present in trace amounts in the crystal lattice of the diamond. Many diamonds are weakly tinted with yellow, but when graded past the "Z" grade on the GIA diamond color grading scale, the color is saturated enough to qualify for the fancy color grading scale, which is as follows: fancy light, fancy, fancy intense, fancy dark, fancy deep and fancy vivid. Yellow diamonds that don't reach the "fancy" grade but still have a pronounced yellow body color are cleverly utilized by today's savvy jewelry designers to create spectacular designs. Some yellow diamonds can have a modifying color which can be orange, green or brown. The fancy yellow diamond color range reflects different strengths of color and a wide range of tones; consumers can pick and choose what works for them. Yellow diamonds occur most commonly in Africa, where many historic stones have been found, including the cushion-shape 128.51-carat "Tiffany" diamond, and the 10.73-carat "Eureka" diamond, the first diamond to have been recognized as authentic in Africa at the beginning of the diamond rush there.



Orange Diamonds
Diamonds with a primarily orange hue are extremely rare, even though orange is often seen as a modifier for yellow, pink and brown diamonds. Orange diamonds tend to be very small and very expensive. The 5.54 carat "Pumpkin" diamond is one of the largest orange diamonds to have received GIA's "Fancy Vivid Orange" designation and was worn in a Harry Winston–designed ring by Halle Berry at the 2002 Academy Awards ceremony.

In April 2010, at the Sotheby's Magnificent Jewels sales in New York, a radiant cut 7.67 carat fancy intense pinkish orange internally flawless diamond was sold for $3,106,500 USD, approximately $404,000 per carat. The GIA stated that the 7.67-carat cut-cornered rectangular modified brilliant cut, type IIa, is the largest "Fancy Intense Pinkish Orange" diamond graded by the GIA to date.

Pink Diamonds
The Argyle Mine in Australia also is famous for its production of fine pink diamonds. The Australian pink diamonds tend to be smaller with a more saturated color than those from India, which tend to have a delicate icy-pink tone. The African pink diamonds, primarily from the Williamson Mine in Tanzania, occur either in light or more saturated hues. Some pink diamonds have purplish, violetish, orangey, or brownish modifying tones. Since pink diamonds are so rare, the intensity of the color and brightness are the most important features. Clarity and cut are secondary. The theory on the source of the pink color in diamonds is that the color is thought to be caused by a process known as plastic deformation, a distortion of the diamonds' crystal lattice.

Natural pinks really took off in 2002, when actor Ben Affleck presented pop star Jennifer Lopez with a $2.5M ring from Harry Winston that sported a 6.1 carat heart-shape cut natural pink diamond. In November 2010, Sotheby’s Geneva sold to Laurence Graff a rare fancy intense pink diamond weighing 24.78 Carats for $46,158,674.

Historic pink diamonds include the rectangular tablet cut "Darya-I Nur" (Sea of Light), which is a light pink diamond weighing between 175 and 195 carats, and combined with another historic diamond, the oval cut 60 carat "Nur Ul-Ain," is thought to be the remnants of the "Great Table" diamond, all believed to originate from India. A more modern historic diamond is the round brilliant cut "Williamson Pink," a flawless 23.60-carat diamond presented to then Princess Elizabeth, now Queen of Great Britain, on the occasion of her marriage to Prince Phillip in November 1947.



Blue Diamonds
Blue diamonds are indeed heavenly in color and the saturation range is from faint to fancy vivid, same as with pink diamonds. Modifying colors for blue diamonds are gray, violet and green. Two important sources for this unusual hue are the Cullinan and Premier Mines in South Africa. Blue diamonds are also found in Brazil and India, but very rarely. Boron in the diamonds' crystal structure is responsible for this alluring color, and most blue diamonds are semi-conductors of electricity.

The fancy color diamond most familiar to people is the steely blue 45.52 carat "Hope Diamond," donated to the Smithsonian Institute in Washington, D.C. by Harry Winston in 1958. What most people don't know about the Hope Diamond is that it glows like a bright red coal under long wave ultra-violet light, and when the light is removed, remains this color for several minutes thereafter.

Other famous blue diamonds include the "Copenhagen Blue" at 45.85 carats, the 52.34-carat oval cut "Eugenie" diamond, and the "Wittlesbach Blue," a 35.36-carat dark blue diamond purchased by famous London jeweler Laurence Graff for $24.5 million at a Christies' auction in December 2008. In May 2009, a cushion-shaped diamond weighing 7.03 carats, fancy vivid blue and internally flawless, sold at Sotheby's for $1,349,752 per carat, for a total of $9.48 million. The diamond, which was cut from a 26.58-carat rough, was discovered in 2008 at Petra Diamonds' historic Cullinan diamond mine in South Africa. In October 2009, at the Sotheby's Hong Kong Autumn Sales 2009, an Emerald-cut 8.74-carat fancy intense blue diamond and diamond ring sold for HK$43.8 million/US$5.6 million - $640,732 PC. In May 2010, at the Sotheby's Geneva Spring Sales of Magnificent and Noble Jewels, a rare cushion-shaped fancy intense blue diamond weighing 7.64-carats was sold for CHF8,930,500 /$8,034,503. This sets a new record price of $1,051,636 per carat for a fancy intense blue diamond sold at auction.



Violet Diamonds
Violet diamonds are the third specialty served up by Australia's Argyle Mine, although it yields a very small portion. Because the hue of violet diamonds is often modified by blue or gray, it can be difficult to assign this color designation. A smattering of violet diamonds was mined in Russia back in the 1990s, but no mine other than the Argyle has produced these diamonds with any consistency. In April of 2009, the Argyle Mine offered a special "Once in a Blue Moon" tender involving violet-colored diamonds. Violet diamonds tend to be less than a half carat in weight and appear low in saturation or intensity and fairly dark in tone. The cause of color in violet diamonds is the addition of a minute amount of hydrogen occurring in the crystal structure. The best known violet diamond is an 8 carat beauty that belongs to the wife of basketball star Kobe Bryant.



Green Diamonds
The most common way for green diamonds to form is when the diamond encounters alpha radioactive particles present in magma or kimberlite rock when being carried towards the surface of the earth in a geologic event. The radioactivity emanating from the alpha particles imparts a thin green "skin" to the surface of the diamond exposed. Because the depth of this coloration is so shallow, great care must be taken when cutting the diamond to leave some of this "skin" on the diamond so it will retain its green color. Consequently, green diamonds of any size are very rare. Green diamonds are found in Africa, India, Russia and South America. The most famous green diamond is the "Dresden Green," approximately 41 carats and set into a hat clasp in the collection of the Green Vaults of Dresden, in Saxony, Germany.



Red Diamonds
Natural red color diamonds are the rarest of the rare, with only a few examples known to exist. The color is due to an unknown structural anomaly in the stone, and, generally, the deeper the color, the more haziness visible in the stone. News of red diamonds always sparks interest from the public, and in 1987 a 0.95-carat round brilliant cut diamond, designated "Fancy purplish-Red" by the Gemological Institute of America, was auctioned and named the "Hancock Red." This stone sold for $880,000, or $926,000 per carat. In 2002, a 5.11-carat triangular-shape diamond, color-designated "Red" by the Gemological Institute of America, was named the "Mousaieff Red" after the jeweler who purchased it.