| The Gemological Institute of America (GIA), the | | | | color from impurities imbedded in the diamond, |
| American Gem Society (AGS), and the | | | | Pink diamonds are considered a Type II and get |
| International Gemological Institute (IGI) are the | | | | their color from a process known as Plastic |
| three most widely known and respected diamond | | | | Deformation. |
| grading laboratories in the world. Each of the | | | | Type II diamonds have very few if any nitrogen |
| grading laboratories have developed a very similar | | | | impurities in them. They get their coloration due |
| nomenclature for identifying the 4 C's of | | | | to structural anomalies caused by Plastic |
| diamonds. | | | | Deformation during the crystal growth. The |
| D to Z | | | | intense pressure changes the lattice structure of |
| Color grading scales used by the internationally | | | | diamonds and has led to the formation of Pink, |
| recognized laboratories (GIA & IGI for example), | | | | and Red colored diamonds. |
| ranges from totally colorless (D) to pale yellow or | | | | Green Diamond |
| brown color (Z). Brown diamonds darker than K | | | | A natural diamond coming into contact with a |
| color are usually described using their letter grade, | | | | radioactive source at some point during its lifetime |
| and a descriptive phrase, for example M Faint | | | | causes some diamonds to develop a green |
| Brown. Diamonds with more depth of color than Z | | | | coloration. The time required may be as much as |
| color fall into the fancy color diamond range. | | | | a million years or longer. Green diamonds of this |
| The coloration of diamonds can be caused by | | | | nature are very unique. |
| several factors. Impurities trapped in the diamond | | | | The most common form of irradiation diamonds |
| during its formation, the crystal lattice structure | | | | comes from alpha particles found in uranium |
| of the diamond, and the exposure to radiation can | | | | compounds or from percolating groundwater. |
| all lead to the wide verity of colors available in | | | | Green spots on the surface of the diamonds or a |
| diamonds. | | | | thin green film may develop on the skin of the |
| Yellow Diamonds | | | | diamond after long exposure to these particles. |
| Yellow diamonds are colored because of the | | | | Many times this green coloration will be removed |
| impurities that are trapped inside diamonds when | | | | during the cutting or faceting process. |
| they are created. If a few of the millions of | | | | Bombardment by beta and gamma rays will color |
| carbon atoms have been replaced by nitrogen | | | | the diamond to a greater depth and in some rare |
| atoms, then structure of the diamond will not be | | | | case turn the entire stone green. Heating to |
| significantly altered but the clarity will be changed. | | | | temperature to just below 600 degrees Celsius |
| The amount of color displayed is dependent on | | | | can sometimes also cause a diamond to develop |
| the amount of nitrogen involved. | | | | a green ting. Higher temperature may turn the |
| When we see color it is because the object we | | | | stone to a less desirable yellow or brown color. |
| are looking at reflected a specific wavelength of | | | | Black Diamond |
| the light spectrum. A good example of this is a | | | | Black diamonds are found only in Brazil and the |
| yellow flower. The flower absorbs all of the light | | | | Central African Republic. Approximately 600 tons |
| except the yellow light, which is reflected by the | | | | of conventional diamonds have been mined, |
| yellow flower. | | | | traded, polished since 1900. But not a single black |
| Blue Diamond | | | | diamond has been discovered in the world's mining |
| In the case of a blue colored diamond some of | | | | fields. The geological settings where diamonds are |
| the nitrogen has been replaced by Boron. Boron | | | | found or mined are virtually identical with the one |
| will reflect the blue wavelength of the light | | | | exception, the Black Diamond. |
| spectrum. The higher the concentration of boron | | | | Black diamonds have been found to contain trace |
| the more color will be showed. At a level of one | | | | elements of nitrogen and hydrogen. The study |
| or a few boron atoms for every million-carbon | | | | published in 2006 analyzed the hydrogen in black |
| atom, an attractive blue color results. | | | | diamond samples using infrared-detection |
| Pink Diamond | | | | instruments and found that the quantity indicated |
| The pink diamonds comes in shades ranging from | | | | that the mineral formed in a supernova explosion |
| a pastel rose, such as the Pink Orchid to intense | | | | prior to the formation of the Solar System. |
| purple-reds of the Moussaieff Red, and the price | | | | These diamonds were formed by carbon-rich |
| is determined by the intensity of the color. Pink | | | | cosmic dust in an environment near carbon stars. |
| diamonds have sold for up to $1,000,000 a carat. | | | | The diamonds were incorporated into solid bodies |
| Unlike the Type I diamonds that derived their | | | | that subsequently fell to Earth as meteorites. |