Aside from white, diamonds are also found in shades of yellow, brown, red, purple, blue and green. The color can be either natural or artificial.
Natural fancy color diamonds get their coloring in different ways. The color can be due to trace elements present in the stones, such as nitrogen, which produces a yellow diamond. The diamond may have been exposed to radiation during its creation; green diamonds are an example of gems affected by radiation. Inclusions, regarded as undesirable in a colorless stone, often contribute unique tones and interesting flashes of color in a fancy color diamond.
It is possible to enhance or change the natural color of a diamond. Fancy color diamonds are becoming increasingly popular, so gemologists have developed ways to create affordable versions by using heat and radiation to turn brownish and yellow diamonds into colorful show-stoppers, at an affordable price.
Treatments make it possible for more consumers to own these vivid diamonds, because most natural colored diamonds are rare and expensive. It is best to assume that any affordable fancy color diamond has been treated in some way. If there are questions as to a stone's origins, ask for a lab certificate to verify its authenticity. If a colored diamond is offered a bargain price, it is safe to assume the color is synthetic.
Unscrupulous sellers sometimes apply coatings to mask or enhance the true color of a diamond. These coatings can be removed by wear or cleaning solutions. Irradiation, followed by high heat treatment, is used to convert brown and yellow diamonds into fancy colors such as green, vivid yellows, blues, purples, reds and other colors. This color change is usually permanent, but could possibly be affected if high heat is used during setting repairs.
High Pressure High Temperature Treatment (HPHT) was first used to turn low-priced yellowish diamonds into fancy colored gemstones, but it is also used to transform them into completely colorless diamonds that can be sold for a much higher price. Some companies claim HPHT isn't an artificial treatment at all, calling it a technique that finishes the job nature started. Certainly diamonds are exposed to such an environment in the earth, and when the process is repeated in a man-made environment it is difficult to detect by examination of the stone. GIA grading reports now indicate when HTPT treatments are detected by stating "HPHT Annealed" or "Artificially Irradiated" in the Origins portion of a report. The FTC requires that any diamonds subjected to HPHT be labelled as such.
Synthetic colored diamonds are also available. These are chemically the same as natural diamonds, but they are created in a lab. The secret to making diamonds was discovered in the 1950s, when diamonds were synthesized almost simultaneously by Swedish and American researchers. This process uses pressures of over 55,000 atmospheres and 1400C, plus molten iron to convert graphite to diamond, were necessary. Currently approximately 80 tons of synthetic diamonds are produced annually by General Electric, De Beers, mostly for industrial use.
However, some companies are also producing high-grade synthetic diamonds, and this process makes ownership of a fancy color diamond a reality for buyers who otherwise could not afford to purchase a natural stone. For instance, a company called Gemesis specializes in producing yellow and orange fancy color diamonds.
Several factors influence the price of colored diamonds. The rarer and more intense the color, the more the diamond will cost. Unlike white diamonds, the presence or absence of inclusions is of secondary consideration. Colored diamonds have a grading all their own, and are categorized by the GIA into 9 different groups : Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Intense, Fancy Deep and Fancy Vivid.
Yellow and brownish diamonds are the most common; blue, green and especially red are the rarest and most valuable. Yellow and pink diamonds are the most commonly purchased, though public tastes may change in the future. Pink diamond sales received a boost from a large pink diamond ring worn by Jennifer Lopez. Celebrity tastes greatly influence trends in the area of luxury products.
Yellow and brown diamonds are sometimes referred to as Champagne diamonds, and they are less expensive than white diamonds. Champagne diamonds with a secondary pink color are extremely popular. When faced up, these stones display light to bold flashes of pink in their fire. These stones are available in a sparkling range of champagne tones, from light champagne to fancy cognac. An extremely pale yellow diamond will be classified somewhere in the X to Z color range, making it closer to a low end white diamond rather than a fancy color. Yellow diamonds of a high intensity, such as vivid or deep, are quite rare and therefor more expensive.
Natural fancy pink diamonds are rare, and account for only a fraction of one percent of the output of the Australian Argyle mine. Pink diamonds mined in India, Brazil and Africa are usually lighter in color than the intensely pink Argyle diamonds. These diamonds are primarily divided into five color categories: Pink, Purplish pink, Brownish pink, Orangey pink and Pink Champagne. Pink diamonds without any secondary coloring are the rarest and most expensive of all.
By volume, the Argyle mine in the Kimberley region of Western Australia is the largest diamond supplier in the world. It is also world's foremost source of intensely colored pink diamonds, producing 95% of the world supply. However, only an extremely small proportion of Argyle diamonds production is Pink color, in fact less than one tenth of 1 percent. The fame of Argyle's pink diamonds has grown over the past decade. At the 1989 Christie's auction in New York a 3.14 carat Argyle pink sold for $1,510,000. Privately, Argyle has sold pink diamonds for up to $1 million a carat.
The Argyle mine, also a leader in the production of brownish diamonds which were previously unwanted by consumers, was the first to introduce the terms ‘champagne’ and ‘cognac’ as a marketing campaign to encourage appreciation of these stones. It seems to have worked, and brown diamonds are becoming more expensive as they are being incorporated more frequently into jewelry.
Within a given grade, clarity, color distribution and cut affect the final price of the stone. Smaller diamonds (less than 0.80) carat can cost 10%-20% less than the rarer large gems. Exceptionally well cut stones and stones with a VVS or IF clarity can cost 10%-20% more. Secondary colors, such as brownish yellow, reduce cost.
A good cut gives a fancy diamond its sparkle and helps to bring out the most intense color possible. White diamonds are cut in a standard way to maximize light refraction. However, when cutting colored diamonds, the cutter usually considers the stone's inclusions, which can enhance the diamond's color. Facets and angles also give color to a diamond, so the cutter must consider what shape would bring out the gemstone's best color.
The best prices are offered by "direct from the mine" wholesalers, merchants who buy either rough stone or newly cut diamonds directly from the source. Not all wholesalers will sell to private buyers, but the ones who do can save their clients a lot of money.