Colored diamonds and their magic

Hidden inside our planet are some of the rarest and most beautiful creations nature has to offer: fancy colored diamonds. Exotic and mysterious, these gems have been prized and admired for centuries with no end in sight. It was once said that “Gems are the flowers of the mineral kingdom and fancy colored diamond is the orchid.” – R.J. Hauy

When colored diamonds come to mind, many people think of yellow, yet nearly every color of the spectrum is possible in nature and some are much rarer than others. To find a pure yellow diamond, one that has no secondary color like brown for example is difficult. The reason is that pure yellow diamonds are the result of nitrogen impurities at the atomic level that replace the carbon atoms in the diamond’s structure. Diamonds that have this pure yellow and most saturated color (vivid) are very desirable to collectors and jewelry lovers the world over.

Positively my most favorite colored diamonds are blue in color, a color that itself is not overly abundant in nature, a few birds like the bluejay or peacock come to mind or certain flowers like the hydrangea. Often associated with the sea or sky, blue is loved by many. In transparent object like diamond, blue results from the way light is absorbed by the material. In the case of natural blue diamonds, a small amount of boron inside the very structure is the cause and these are known as type IIb diamonds. On very rare occasions these type of diamonds can have a pure blue color like a sapphire. The greenish blue and blue green stones like the one in this photo owe their teal color to natural radiation that created defects in the structure of the diamond itself.

References to blue diamonds go back centuries and the most famous stone would have to be the 45.52 carat Hope. In Archibald Billing’s book, The Science of Gems (1875), he mentions that “diamonds are found in every color of the rainbow – red, orange, yellow, green and blue, as, for instance, the celebrated blue diamond in the collection of Mr. Hope.” Without rival and the color of the most beautiful blue sapphire the Hope is and will be the most famous diamond in existence.

To understand the rarity of these gems one must go beyond looking at just color even though it is the most important factor. You consider other aspects like size, and diamond type (1a, 1B, type IIb etc)  While it is true that all natural colored diamonds are rare, there are differences in rarity among the various colors and certain colors are more rare than others. If you pick your favorite color of a natural fancy diamond Рit will have a story of how it got its color Рpink diamonds have deformations in their crystal structure, green diamonds have natural radiation etc. The most rare color a diamond can have is red, so rare in fact that literally only a handful exist. Another interesting fact about red diamonds is that they are so rare that even if the red color is the modifier, or the secondary color, the price skyrockets. Like pink diamonds, the red stones receive their color from plastic deformation of the crystal lattice from temperature and pressure when forming. Gem collectors who are in the know are aware that a pure red diamond has an almost fictitious existence, and as a result very few red stones have ever been reported.

I only touched on a few aspects of colored diamonds, as one could write volumes on just a single color. Currently there is no doubt that colored diamonds are the most valuable gemstone on the planet, as determined on a price per carat basis. As news of these exceptional stones surface from time to time, whether at a high end auction house or your favorite celebrity – you can be sure that this rarefied item will only continue to go up in price as the years go on.

Author: Shawn

Indiana University Alumni GIA Graduate Gemologist Student

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