Fancy Colored Diamonds
Natural Fancy Color
Diamonds come in a multitude of colors, each one of them sparkling with their own special mystery and beauty. As unbelievable as it may seem, natural diamonds exist in virtually every shade of color known to man! Among the varied colors are strawberry red, pistachio green, pumpkin orange, chocolate brown, canary yellow, cotton candy pink, seaweed olive, burgundy-purple, gun-metal gray, steely black, and every shade in between.
The majority of rough crystals, from which diamonds are fashioned and finished, typically have some degree of modifying color. Although yellow, brown, and gray are the most common, the lucky natural crystals that have special hues, such as blue, green, orange, pink, red, and purple, are extremely rare. These rare color combinations are deemed “fancy colors.”
They owe their color to trace elements that are mixed with the carbon as a diamond crystallizes deep within the Earth’s crust if it is exposed to a natural radiation source while crystallizing, or subjected to extreme pressures at birth. Blue owes its color to boron in the mixture; yellow, oranges, and browns to the presence of Nitrogen; green to a nearby radiation source; and other colors due to aberrations within its crystal structure that affect its optical characteristics.
The 4 C’s of color, cut, clarity and carat weight apply to colored diamonds just as they do to colorless diamonds, with the exception of the intensity of color, not the lack of it! The purity and intensity of the spectral color are directly proportional to the price. Most natural fancy colors come in hues with a secondary modifying color, i.e. brownish-orange or purplish-pink.
But the overwhelming factor that affects the evaluation of any fancy diamond the most, is whether or not its color is from the natural creation of the diamond itself, and not through any enhancement other than the actual cutting and polishing. These are then deemed “Natural Fancy Color Diamonds.” This distinction is extremely important! We disclose the origin of color in every fancy colored diamond we sell.
Treated Fancy Color
In the early 1900s, the first instance of colorizing a diamond by unnatural means was conducted by a British scientist. Diamonds were placed in radium salts for an extended period. Unfortunately, the stones became radioactive in the process and the coloration only penetrated the outermost surface of the stones. In the 1940s, diamonds were “greened” by exposure to high-speed bombardment by atomic particles in a cyclotron. This treatment achieved a safe, fast, and permanent way of modifying its otherwise unwanted natural color. By coupling irradiation techniques and heating to very high temperatures, diamonds were available in greens, blues, yellows, browns, and blacks on a commercial scale in the 1950s. Most recently, with the evolution of particle acceleration generators and nuclear science, pinks and purples have been produced! Irradiated diamonds usually retain their new color, however, they can change color if heated by a jeweler’s torch.
These irradiated or treated diamonds are still commercially marketed, but they are treated from off-color or diamonds that would be otherwise undesirable. The colors they reproduce, although fancy, is not exactly the same as untreated natural fancy color diamond. Treated diamonds sell at a fraction of their natural color counterparts, and usually sell for substantially less than their colorless cousins! Therefore, they are still shunned by most for the same reason that most people do not want Cubic Zirconia in place of a diamond: even though it bears a resemblance, it can not match the value or beauty of the real item! There is also the human factor: once you know something is not the real thing, it somehow is tarnished and never appears the same!
Certification as a Fancy Natural Colored Diamond
With demand for natural fancy color diamonds at the greatest levels in history, and prices commanding all-time high prices, it is all-important to know whether or not a fancy color diamond’s color is natural. Very often, irradiated stones may visibly appear to have color concentrations in areas of stones, hence “color zoning”, or reveal these defects under magnification. The irradiated colors also tend to have an unusual color appearance not commonly seem in natural fancy colors. However, the only way to be absolutely certain of its natural origin is by taking a spectral analysis of the stone.
Therefore, it is paramount that the stone is accompanied by a certificate of its natural origin. This procedure is done by an accredited laboratory for such testing, such as, Gemological Institute of America (GIA), AGS Laboratories (AGS), or a skilled gemologist who has the knowledge and spectrometer that is required.
The way natural fancy color diamonds are graded is totally different from those used with colorless diamonds (as a color grade in the 4 Cs). The GIA color scale for colorless to near-colorless diamonds are arranged to start at D color, the purist colorless grade, through Z color, where the diamond has a very perceptible tint of yellow. This is good for grading colors that have any trace of yellow, however, they do no account for the other most common modifying colors typically found in white diamonds, namely brown and gray.
In grading for fancy color diamonds, there is one universal grading system that has been devised by GIA (and copied by other labs) to accurately grade all the fancy colors relative to the colorless (D) grade and with the exception of browns. Natural fancy color diamonds are judged by the visual appearance by hue, saturation, and tone.
Hue is defined as the primary spectral color, which can be modified by a secondary spectral color. For example, say a stone is graded with a pure yellow color, it would be described as a fancy yellow. If the modifying hue comprises up to 25% of the color, it is referred to as orangish-yellow. If the modifying hue comprises 25-50% of its color, it is referred to as an orange-yellow. Once the hue comprises more than 50%, it is then graded as the primary color.
Saturation is the intensity of the hue, for example, faint, intense, vivid. The tone is the lightness or darkness of the diamond ranging from clear to opaque or whiteness to blackness, for example, very light, light, medium, dark.
The Color Scale Terms for Distinct Colors: Faint (where the color is barely distinguishable from the colorless), Very Light, Light, Fancy, Fancy Intense, Fancy Deep, and Fancy Vivid (where the color is extremely bright and vivid). These terms are coupled with a description of the primary and modifying fancy color and tone, for example, Fancy Purplish-Pink, Fancy Vivid Orange-Pink, Very Light Brownish-Pink, etc.
Brown color diamonds have their own dedicated and separate grading scale, provided that their color is a pure brown hue, and not a modifying color, such as brownish-pink. We will go into further explaining grading for fancy browns in “Champagne Diamonds” in the section outlining special colors. Gray is not a color that typically affects many fancy color diamonds other than blue and black diamonds, and once a diamond is tinted so overwhelmingly by the gray, it becomes opaque anyway.
The intensity of color in natural fancy color diamonds is directly proportional to its rarity and price, and only a few have been discovered as the color becomes more vivid.
For further information about the varying colors, etc. please see Natural Colored Diamonds Association (NCDIA) and Gemological Institute of America (GIA).