Why Are Some Diamonds Colored

The Gemological Institute of America (GIA), thecolor from impurities imbedded in the diamond,
American Gem Society (AGS), and thePink diamonds are considered a Type II and get
International Gemological Institute (IGI) are thetheir color from a process known as Plastic
three most widely known and respected diamondDeformation.
grading laboratories in the world. Each of theType II diamonds have very few if any nitrogen
grading laboratories have developed a very similarimpurities in them. They get their coloration due
nomenclature for identifying the 4 C's ofto structural anomalies caused by Plastic
diamonds.Deformation during the crystal growth. The
D to Zintense pressure changes the lattice structure of
Color grading scales used by the internationallydiamonds 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 orGreen Diamond
brown color (Z). Brown diamonds darker than KA 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 Faintcauses some diamonds to develop a green
Brown. Diamonds with more depth of color than Zcoloration. 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 bynature are very unique.
several factors. Impurities trapped in the diamondThe most common form of irradiation diamonds
during its formation, the crystal lattice structurecomes from alpha particles found in uranium
of the diamond, and the exposure to radiation cancompounds or from percolating groundwater.
all lead to the wide verity of colors available inGreen spots on the surface of the diamonds or a
diamonds.thin green film may develop on the skin of the
Yellow Diamondsdiamond after long exposure to these particles.
Yellow diamonds are colored because of theMany times this green coloration will be removed
impurities that are trapped inside diamonds whenduring the cutting or faceting process.
they are created. If a few of the millions ofBombardment by beta and gamma rays will color
carbon atoms have been replaced by nitrogenthe diamond to a greater depth and in some rare
atoms, then structure of the diamond will not becase 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 oncan 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 westone to a less desirable yellow or brown color.
are looking at reflected a specific wavelength ofBlack Diamond
the light spectrum. A good example of this is aBlack diamonds are found only in Brazil and the
yellow flower. The flower absorbs all of the lightCentral African Republic. Approximately 600 tons
except the yellow light, which is reflected by theof conventional diamonds have been mined,
yellow flower.traded, polished since 1900. But not a single black
Blue Diamonddiamond has been discovered in the world's mining
In the case of a blue colored diamond some offields. The geological settings where diamonds are
the nitrogen has been replaced by Boron. Boronfound or mined are virtually identical with the one
will reflect the blue wavelength of the lightexception, the Black Diamond.
spectrum. The higher the concentration of boronBlack diamonds have been found to contain trace
the more color will be showed. At a level of oneelements of nitrogen and hydrogen. The study
or a few boron atoms for every million-carbonpublished in 2006 analyzed the hydrogen in black
atom, an attractive blue color results.diamond samples using infrared-detection
Pink Diamondinstruments and found that the quantity indicated
The pink diamonds comes in shades ranging fromthat the mineral formed in a supernova explosion
a pastel rose, such as the Pink Orchid to intenseprior to the formation of the Solar System.
purple-reds of the Moussaieff Red, and the priceThese diamonds were formed by carbon-rich
is determined by the intensity of the color. Pinkcosmic 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 theirthat subsequently fell to Earth as meteorites.