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Roger Weller, geology instructor

Colored Diamonds
Caitlin Henry
Physical Geology
Fall 2007

                                                         Causes of Color in Diamonds and their Value


                  Researchers believe that diamonds were formed two to three billion years ago when carbon bearing rocks deep beneath the earths surface, precisely a hundred feet or more, were put under immense pressure and heated up to about 2,200 degrees Fahrenheit.  The pressure and heat caused the carbon molecules to dramatically rearrange. When the temperature reduces,  if other conditions like pressure and chemistry are right, the carbon atoms in the melting crustal rock bond to build diamond crystals.



                  The formation of natural color diamonds is a process that requires the presence of not only the naturally occurring formula for all diamonds, but also the presence of additional trace elements and distortions to the typical diamond crystal. If an element interacts with the carbon atoms during diamond creation, the diamond’s color can change. Radiation and pressure on a diamond’s structure will also impact its color. The colors we see today may have many different shades but which ones are naturally colored and which ones are artificially colored is a hard question to answer. Several people will add artificial substances to a beautifully created natural substance in order to make more money but how they insert the material is a tricky task for most.



       Fancy colored diamonds are all the rage these days. Gemologists have developed new ways to create versions that are affordable for the average person by treating less desirable diamonds with irradiation followed by intense heat. This turns brown and yellowish diamonds into beautifully colored diamonds that you can afford. This procedure produces stunning pinks, blues, yellows, reds, purples and other colors. These colors are considered permanent, but there is a possibility they could change during repairs if a high heat is used.

Pink Diamonds

            Naturally colored pink diamonds are some of the rarest and most desired colored diamonds on earth. Chard Diamonds says “The Darya-I-Nor diamond is the largest pink diamond in the world at about 185 carats. Naturally colored pink diamonds are so rare that over half the jewelers on earth will never even see one, let alone own one”.  The beauty and rarity of this particular diamond makes its price astronomical. Naturally colored pink diamonds can range in price anywhere from four million to four thousand dollars yet their formation is simply caused by an imperfection in the crystal lattice of the diamond. Synthetically enhanced pink diamonds are another story.  They can be found in almost any jewelry store and are generally real diamonds but they have been treated to look pink. These diamonds can range from one hundred and fifty five to eighty nine dollars.


Blue Diamonds

      Natural Blue Diamonds are also extremely rare but they are becoming steadily easier to find due to mining in new areas.  These diamonds are formed when traces of boron are present during the diamond’s creation. Chard Diamonds says “The Hope diamond, which we have viewed in the Smithsonian Institution in Washington D.C., is the most famous blue diamond in the world, and the largest at 45.52 carats.” The Millennium Dome Diamond Robbery was an attempt to steal 12 large diamonds valued at a total of £200 million, an average of over £16 million each. Eleven out of the twelve diamonds were blue diamonds. The blue diamond has a wide range in color starting from a pale light blue to a beautiful deep almost navy blue. The most commonly found blue diamonds are a beautiful aquamarine. Synthetically enhanced blue diamonds in all color ranges can cost anywhere from four hundred to sixty five dollars.   


Yellow Diamonds

         Arknsas is famous for its yellow diamond mines, although, other colred diamonds have been uncovered in these mines as well. The naturally occuring yellow diamond is created by trace elements of nitrogen being infused during the diamond’s formation. Most people believe that yellow diamonds are less desirable and valuable than white diamonds. While this is true of faintly colored or off-white diamonds, intensely colored diamonds are very attractive, rare and expensive. The Kimberley Octahedron is the largest diamond in the world at about 616 carats, and it is yellow. Yellow diamonds are a beauty only a few people see but their price is just as big as the other colored diamonds. The price of a precious yellow diamond usually ranges anywhere from two hundred and ninety seven to Ninety-five thousand dollars. The synthetic yellow diamonds are rarely created because they are often undesirable unless they are of natural origin. When synthetic yellow diamonds are created, however, they can be as cheap as ten dollars or as expensive as one hundred dollars depending on the make and design.

Red Diamonds

      Red diamonds are among the rarest jewels on earth. So rare, in fact,  that not much is known about where they can be found or even the range of color shades that might exist.  These diamonds are also thought to be created simply by an imperfection in the crystal lattice.  Chard diamonds says “The Moussaieff Red Diamond is a diamond measuring 5.11 carats (1.022 g) with a triangular brilliant cut (sometimes called a trillion or a brilliant cut), rated in color as Fancy Red by the Gemological Institute of America.” While this may seem relatively small when compared to other famous diamonds, the Moussaieff Red is, in fact, the largest Fancy Red the GIA reports having rated. The Moussaieff Red is reported to have been found by a Brazilian farmer in the mid-1990s as a rough of approximately 11 carats (2.2 g). Natural red diamonds are the rarest and most expensive diamonds anyone can come across their prices are generally sky high costing anywhere from twenty thousand dollars to two point six million.


Purple Diamonds

        Purple diamonds are yet another precious stone thousands of people desire. A purple diamond recently assessed by the British Gemological Institute has been estimated to be worth over £14 million, and to be the most valuable natural object in existence on a weight for weight basis. This stone weighs between four and five carats. There is a larger purple diamond on display at a Paris museum, but its color is paler. Purple diamonds can be priced at a pretty penny of nine hundred thousand to forty six hundred dollars. Synthetic purple diamonds are of a somewhat lesser price ranging from ninety eight to forty six dollars.


Color Grade


        Many experts name color as the number one consideration in choosing a diamond. A diamond's color is graded on an alphabetical scale from D-Z, with D being absolutely colorless and Z being light yellow. Beyond "Z", a diamond is considered to be an exotic or "Fancy" color. Since color differences can be so subtle, they are impossible to determine by the untrained eye. To grade a diamond, gemologists often place it on a white background next to another diamond that has been previously graded.



























Near Colorless

Faint Yellow

Very Light Yellow

Light Yellow


   There are several other colors in the realm of diamonds not listed in this paper that are caused by different natural elements. The color of diamonds has a giant effect on the amount of desire and a huge effect of their price.  The color of a diamond can make or break its price value along with its size.

Special Reference:  How Colored Diamonds Are Made



Blue Diamonds by Chard.

Golden Key Diamonds.Google.
Pink diamonds by chard. Google.May 12.2001

Famous Historical and Notable diamonds. Google.
Yellow diamonds by Chard. Google.May 12.2001
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