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Colored Diamonds

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Most people think of diamonds as colorless, but most diamonds have a small amount of color, usually yellow or brown. Truly colorless diamonds command high prices, but the prices of naturally colored diamonds are also spectacular.


Diamonds in colors outside of the normal color range are called colored diamonds and they are far more rare then diamonds in the normal color range. Some experts estimate that only two percent of total diamond rough is fancy colored. Their popularity and availability have increased in the past decade. From red to green, blue, purple and orange, they exist in a rainbow of colors, caused by factors such as geologic forces, exposure to radiative minerals, or atoms from trace elements being trapped in a diamond’s crystal lattice.  Yellows and browns are the most common diamond color. 

Two conditions influence the way a diamond absorbs the light and, in turn, determines its color. One is the presence of impurities, and the other is structural defects, like missing atom in the crystal structure.

Natural pink to red diamonds are among the rarest and most desired fancy colored diamonds. Red diamonds are so rare that only a handful are known to exist. How pink and red diamonds form is still a mystery- but scientists have observed that the vast majority of pink diamonds have 550 nm absorption band, which indicates that shear stress and deformation of the crystal structure had occurred while the diamond was deep within the earth. 

Blue diamonds are also very rare. They generally have a slight hint of grey, so they are rarely as highly saturated as blue sapphires. Their color is caused by the presence of boron impurities- the more boron, the deeper the blue. Blue diamonds have a surprising ‘super deep’ origin and a link to ancient oceans.When seawater infiltrates the ocean floor, it causes chemical reactions that deposit boron into the oceanic lithosphere. Some of this boron is subducted with water bearing minerals down to the lower mantle. At this depth, the increase temperature and pressure break down the minerals, which then release a boron enriched fluid that triggers diamond growth.

Fancy green diamonds are typically light in tone and low in saturation. They get their green color when radiation displaces carbon atoms from their normal positions in the crystal structure. This can happen naturally when diamond deposits lie near radioactive rocks, or artificially as a result of treatment by irradiation. For this reason, green diamonds are  always regarded with suspicion and examined carefully in gemological laboratories. 


With colored diamonds, more color usually means higher value, so the brightest, purest colors are the most desirable. In pink, green and orange, even fancy color diamonds below a carat are rare and valuable.

Colored diamonds are priceless wonders of nature. Spectacular prices in high profile auctions are another factor in the increased awareness of colored diamonds. In May 2012, at Christie’s Hong Kong, a 12.04-ct Fancy Intense Pink Diamond sold for $17,395,728 -a price that amounted to about $1,444,823 per carat.

Austraria’s Argyle mine is famous for producing rare and valuable pink and red diamonds, but most of the mine’s diamonds are brown -to- yellow color range. Brown is the most common colored diamond and also the earliest to be used in jewelry. Second century Romans set brown diamonds in rings. In modern times, they took some time to become popular. Golden or reddish appearance is typically the most popular. In 1980s Argyle mine in Australia began marketing them under trade names like ‘Champagne’ and ‘Cognac’ making the public more aware of of fancy color diamonds. 

Yellow is  by far the second most common fancy color, while those with an unmodified orange hue are among the very rarest. Both orange and yellow diamonds owe their color to nitrogen related defects.

South Africa is also the largest producer of the high value diamonds in blue, yellow and pink hues. Other well known historical and current sources of  fancy color diamonds are India, Brazil, Venezuela and Indonesia.

There is no way to know what new Diamond color will be unearth next and how it will affect the diamond market. But all colored diamonds can have a stunning impact on jewelry design. 

 Overview

1 in 10,000 diamonds has fancy color.

$71.2 million - in April 2017, the Pink Star diamond, 59.60 carats, became the most expensive gem ever auctioned.

Hope Diamond -the 45.52 carat Fancy Deep blue diamond is the world’s most famous gem.

 

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