In diamonds, rarity equals value. With diamonds in the normal range, value is based on the absence of color, because colorless diamonds are the rarest. With fancy color diamonds—the ones outside the normal color range—the rarest and most valuable colors are saturated pinks, blues, and greens. In all cases, even very slight color differences can have a big impact on value.
Brown is the most common fancy diamond color and also the earliest to be used in jewelry. Second-century Romans set brown diamonds in rings. In modern times, however, they took some time to become popular.
Brown diamonds were typically considered good only for industrial use until the 1980s, when abundant quantities of them began to appear in the production of the Argyle mines. The Australians fashioned them and set them in jewelry. They gave them names like “cognac” and “champagne.” The marketing worked, and brown diamonds, sometimes called "chocolate" are found in many medium-priced jewelry designs today.
Yellow is diamond’s second most common fancy color. Yellow diamonds are sometimes marketed as “canary.” While this isn’t a proper grading term, it’s commonly used in the trade to describe fancy yellow diamonds.
The GIA system for color-grading fancy color diamonds is designed to accommodate the fact that not all colored diamonds have the same depth of color. For example, yellow diamonds occur in a wide range of saturations, while blue diamonds do not.
Diamonds with red or reddish colors are extremely rare and highly valued. Pure pinks are more popular than diamonds that are purplish, orangy, brownish, or grayish. Trade professionals market some very attractive stones in this category as “rose-colored,” and some stones with purplish tints as “mauve” diamonds.
Blue diamonds are extremely rare...think of the "Hope Diamond". They generally have a slight hint of gray, so they’re rarely as highly saturated as blue sapphires. Their color is caused by the presence of boron impurities—the more boron, the deeper the blue.
Fancy green diamonds are typically light in tone and low in saturation. Their color often appears muted, with a grayish or brownish cast. The hue is generally in the yellowish green category. In most green diamonds, the hue is confined to the surface, and rarely extends through the entire stone. That’s why cutters try to leave as much of the natural rough around the girdle as possible.
Green diamonds get their color when radiation displaces carbon atoms from their normal positions in the crystal structure. This can happen naturally when diamond deposits lie near radioactive rocks, or artificially as a result of treatment by irradiation.
You can find treated colored diamonds, which should always be disclosed, using a multi-step process that involves HPHT annealing, irradiation, and low-pressure annealing at relatively lower temperatures. They can be more affordable. Like any diamond, shape, cut inclusions, can all play factors in the beauty of the stone.
If you want to see some amazing colored diamonds, some natural, some treated, come into b. shannon designs!