How are natural color diamonds created? After all, fancy colored diamonds are found in such a wide range of colors and shades. Yellow diamonds come in light yellow to a rich canary color. And fancy blue diamonds are available in a choice of shades from sky blue to a steely-type blue darker than sapphires. There are red and green diamonds, orange, champagne and many others.
Colored diamonds obtained their color due to many factors during the formation process, and include pressure, atoms or other elements, or natural radiation. Where there was nitrogen, the outcome was yellow, orange and brown diamonds. Among orange diamonds, the purest do not have any traces of brown or yellow. They are extraordinarily rare, and experts believe the color is due to a combination of nitrogen and deformities in their structure.
What is the cause of blue diamonds? Their color derives from the presence of boron during the formation process. The more boron atoms, the more intense the color is. But there are also greenish-blue diamonds, where the color could have come from the presence of radiation in the earth at the time. In outstanding cases, a grayish-blue color has been discovered to be caused by the presence of hydrogen.
Meanwhile, pink, purple and some brown diamonds are the result of a distortion, or deformation, of the crystal lattice in the diamond, known as ‘graining’. Diamond experts estimate that this due to the extreme pressures that the diamonds were under as they made their way to the surface of the earth. It is also believed that this pressure is the reason why many of the diamonds in this color range, especially pink and purple ones, often have a lot of impurities. This is often seen in diamonds from the Argyle mine in Australia. The diamond will enjoy a different shade contingent on the level of graining.
The existence of hydrogen in the diamond’s crystal lattice led to the creation of pure violet diamonds, which are so uncommon that they are practically non-existent.
As for gray diamonds, they derive their color from hydrogen atoms and, sometimes, small quantities of nitrogen.
Natural green diamonds are extraordinarily rare and were caused by gamma radiation to which certain diamonds were exposed during a period that could have lasted for several million years. The gamma radiation led to the displacement of atoms in the crystal structure of the stones. It has been known, although extremely rare, for the existence of hydrogen atoms to lead to a grayish-green color.
Natural red diamonds, the rarest of colored diamonds were formed by the distortion of the atomic lattice in some diamonds, known as ‘plastic deformation’.
What distinguishes natural colored diamonds?
As with all diamonds, it’s all about sparkle and life – a great cut brings out the color and sparkle of the gem.
An acceptable level of purity – meaning that no striking inclusions can be seen with the naked eye, and the impurities are consistent with the general color of the diamond.
A uniform, or constant, color. The diamond should not have any areas where the color is stronger or weaker.
Colors for natural color diamonds are set by the world’s largest gem lab, the GIA, with its color scale used everywhere. A diamond’s color is decided using to the following reasons:
Hue: the primary color of a diamond, such as blue, green, brown, pink or yellow. There can also be modifiers, or tints, which give more than one hue to the gem which would effectively put it in another color category. A purplish-pink diamond means a pink diamond with purplish tints. However, if there aren’t any such tints, the hue of the stone is said to be a pure primary color
Tone: this relates to how light or dark a stone appears, and depends on how much brown, black, gray or white there is
Saturation: the strength or intensity of the hue or main color. The saturation of lightly toned diamonds varies from light to fancy, intense and vivid. Darker diamonds vary from deep to dark in description
Distribution: how evenly the color is spread throughout the stone
The essence of Fancy Color Diamonds
Fancy color describes a diamond’s color in relation to the traditional color scale used for colorless diamonds. Most mined diamonds are in the colorless to light yellow range (D to Z grade).
However, fancy color diamonds are different, as they have a distinct and rich color. Whereas colorless and near colorless diamonds are valued for their lack of color, fancy color diamonds derive their value from the intensity and distribution of their color. They are extremely rare and tend to be mostly small weighing one carat or less. Their rarity is illustrated by the fact that for every 10,000 colorless diamonds of gem quality, only one natural color diamond is mined.