subject: The Sources Of Color In Fancy Diamonds [print this page] Diamonds are gemstones of perennial popularity. While most of us are familiar with the more common colorless or clear specimens, some may not realize that these gems also may be colored or "fancy". Structural deformations, irradiation, and trapped impurities create color. These shades are rare among mined stones, but high-quality man-made "cultured" jewels often feature the brilliant hues that are so highly prized.
According to the Gemological Institute of America, clear, yellow, and brown in the D-Z range of color fall into the normal range. Yellow and brown stones with a more intense hue than Z, as well as any other color in any intensity, are considered fancy diamonds. The various shades are as follows, listed from most common to rarest: clear, yellow, brown, blue, green, black, translucent white, pink, violet, orange, purple, and red.
Colors are created by impurities trapped within the rock during formation, such as nitrogen and boron. Nitrogen results in yellow and brown, boron generally causes gray blue, and green stones are the result of exposure to radiation. A structural defect called plastic deformation causes pink and red shades.
Only 0.01% of natural diamonds are fancy colored, which is why they are so costly. However, tinted specimens can also be man-made. Modern "cultured" stones are chemically, physically and optically identical to natural mined gems, and most feature brilliant, intense hues such as blue, yellow, pink and even red. These gem-quality synthetic stones are created by high pressure, high temperature synthesis (HPHT) or chemical vapor deposition (CVD). Naturally occurring clear stones can also be modified through HPHT treatment, which will produce tints ranging from green, yellowish green, yellow, pink or blue.
There are many famous examples of fancy jewels. For example, the Aurora Butterfly of Peace is a mosaic created completely from stunning fancy diamonds. The materials were collected one stone at a time over a period of twelve years. Symbolizing mankind's connection to the earth, the breathtaking piece includes purple jewels from Russia, blue and orange specimens from South America, pink stones from Australia, and Brazilian green gems.
Cut in a pear shape and weighing 33.74 carats, the Amsterdam diamond is one of the largest black gems in the world. Originally mined in Africa, this rare jewel sold at auction for $352,000.
The deep blue Hope Diamond is quite infamous, weighing in at 45.52 carats. It is believed by many to be cursed. Legend states the gem was stolen from the eye of an idol, and its owners are doomed to misfortune. There is no evidence supporting the curse; the fiction merely adds mystique and creates an interesting sales pitch. It is now on display at the National Museum of Natural History in Washington, D. C.
The largest fancy diamond in the world is the Golden Jubilee, a yellow brown stone that weighs 545.67 carats and is faceted in a fire rose cushion cut. The Golden Jubilee is now part of the crown jewels displayed in the Royal Thai Palace.
Because of their rarity, these unique stones have primarily belonged to royalty or the fabulously wealthy in the past. However, current interest in fancy gems is on the rise, with more and more celebrities sporting these unusual jewels. Fortunately, gem-quality man-made stones are available in many brilliant colors, and are generally one-third cheaper than mined gems. The increasing availability of cultured diamonds means that fancy colored gems are far more accessible than ever before.
