The Causes of Color in Natural Fancy Colored Diamonds

Meet carbon, the much maligned element of life, your "footprint," and exhale. Here, we discuss carbon in its more desirous form, diamonds. We will shed light on the causes of naturally occurring color in natural fancy colored diamonds, the rarest, most spendid forms of carbon in nature's creation.

Color

Traditional white diamonds are carbon, pure and simple and fully packed in its tight chemical structure. Colored diamonds have slight impurities within, imparting particular colors to an ordinarily clear, colorless stone. Color can also arise from a compromised chemical structure, caused by extraordinarily high pressures or natural radiation.

You can imagine that diamonds might be irradiated by unnatural forces--by human beings looking to give color to white ones or even manmade diamonds. This happens with much more frequency than we think, but the subjects of this writing are the diamonds nature alone created in colors.

Yellow

The most famed of natural colored diamonds are the yellows, often marketed with less pejorative nomenclature as "canary" diamonds. The presence of nitrogen impurities make for the yellow color.

South Africa sources most of the natural yellow diamonds on the market. The largest is the 205-carat "Red Cross" yellow diamond. It was mined by DeBeers and so named for the Maltese Cross reflected in the facets. The name draws significance also from DeBeers donation of the diamond to Christies, which auctioned it off for the benefit of the British Red Cross.

Brown

Browns are the most commonly occurring colored diamonds to be found. They constitute about 80% of the colored diamonds mined at Argyle Mine, Western Australia's--perhaps the world's--most prolific diamond producer.

Marketers call the brown color of diamonds by different names, including the irresistible temptations of 'cognac,' 'chocolate,' and the deep orangey afterglow of sunset.

The brown color is caused not by impurities nor cognac or chocolate, but by a compromised parallel grain structure within the diamond.

Blue

Boron impurities are responsible for the color of blue diamonds. From light to sky blue to nearly navy, the cool blue color in diamonds exhibits a wide range of intensities.

You might have seen Kate Winslett wearing a blue gemstone necklace in the movie, "Titanic." While the stone in that particular piece was sapphire rather than real diamond, it suggested the very real Hope Diamond, a 45.52-carat light blue diamond. Currently resting in the Smithsonian Institute, the Hope Diamond has delivered everything but to its owners, including--it is said--Marie Antoinette's head to the guillotine.

Green

Green diamonds result from radiation. After diamonds form deep within the earth, radioactive rocks emitting radiation nearby color already formed diamonds to green. Such natural irradiation occurs over millions more years. And the green color occurs towards the surface rather than throughout the stone.

As such, natural green diamonds show low color saturation and have a grayish cast. They are, as well, quite rare.

Violet and purple

The presence of hydrogen impurity causes diamond to impart a violet color. Purple, on the other hand, is a color imparted by excessive pressure during formation.

What's the different between violet and purple? It is in the beholder's eye or a gemologist's report, but according to official gemological diamond color scales, violet exhibits a darker, slightly more grayish hue than purple. The two colors, although similar, may arise from entirely different causes.

Deep red

The rarest of all natural fancy colored diamonds is deep red. They are so exceedingly rare as to make them unencountered by even the most experienced career gemologists. The ordinary person's chance of coming across one casually is slim and none, nevermind that one carat of cut deep red natural diamond will set you back a cool half million. In dollars.

The deep red color comes from those tremendous pressures exerted for eons that cause the naturally occurring regular diamond structure to, well, collapse. From such high-pressured stress, you would collapse and turn red too! The same high pressure that brought us pink, purple, and brown-colored diamonds cause the deep red color too, but much less frequently. Oh, well.

The right color for you
Pick your color and tell me your favorite. Then put the pressure on, ladies, or save your pennies, gents, to pick one up for yourself. Because a diamond of any color whatsoever is forever!

Sources:
http://www.ncdia.com
http://www.mapsofworld.com/referrals/metals/diamond/red-cross-diamond.html
http://www.cyber-depot.com/titanic.html
http://mineralsciences.si.edu/hope.htm
http://gia4cs.gia.edu/cm/grading-reports/colored-diamonds.htm
http://gia.edu
http://www.gemnation.com