Intensity

Grading fancy color diamonds is complex and specialized, and takes highly trained laboratory graders to complete the process accurately.

The GIA system for color-grading fancy color diamonds is designed to accommodate to 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.

Intensity list

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. 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.

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.

Naturally colored green diamonds are extremely rare. Because of their rarity and the very real possibility of treatment, green diamonds are always regarded with suspicion and examined carefully in gemological laboratories. Even so, advanced gemological testing can't always determine color origin in green diamonds.

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. The grave them names like “cognac” and “champagne”. The marketing worked, and brown diamonds are found in many medium-priced jewelry designs today.

Brown diamonds range in tone from very light to very dark. Consumers generally prefer brown diamonds in medium to dark tones with a warm, golden to reddish appearance. They generally show a hint of greenish, yellowish, orangy, or reddish modifying colors.

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.

Until the late 1990s, there was not much demand for black diamonds. But designers started using them in jewelry, especially contrasted with tiny colorless diamonds in prave setting, and they began to gain in popularity.

Fancy white diamonds also exist. They have milky white color. Sometime white diamonds are cut to display beautiful opalescent flashes of color.

There are also gray diamonds. Most of them contain a high level of hydrogen as an impurity element, which probably causes their color.

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