Natural colored diamonds are unparalleled in their range of colors and rarity, making them the most expensive of all gems — especially blue, pink, green and red. The color combined with the diamond’s sparkle and brilliance make them the ultimate connoisseur gemstone. Often referred to as fancy colored diamonds, these stones are unsurpassed in beauty and add high-voltage glamour to a piece of jewelry.
- Green diamonds get their color when they reside close to a natural source of radiation in the earth for millions of years.
- Blue diamonds get their color from traces of the element boron.
- Pink diamonds get their color from a twist in the internal structure of the diamond that is created by the high- temperature, high-pressure conditions in the earth.
- Yellow diamonds get their color from the presence of nitrogen in the stone.
It is extremely rare to get a diamond that is a pure color. There is almost always a modifying shade that will shift the color of the stone. For example, a pink diamond may have an orange or purple modifier totally changing the color of the pink. Modifying colors, or lack of modifying colors, also change the value of the diamond. For these reasons, natural colored diamonds are always cut to bring out the most optimum color.
The most important factor in determining the value of a natural colored diamond is the vividness of color. The Gemological Institute of America (GIA) has created a system to grade these rare treasures. Natural colored diamonds are evaluated by:
- tone of color — a scale of light to dark;
- saturation of color — ranging from weak to strong;
- hue — the terms used to describe the color.
The stones are then put into one of the following six categories based on color appearance in the face up position.
- Fancy Light and Fancy describe more pastel tones.
- Fancy Vivid and Fancy Intense are generally considered the most desirable grades because the color appearance is more balanced.
- Fancy Deep diamonds are generally lower in saturation yet deeper in tone. These diamonds can be quite coveted.
- Fancy Dark diamonds are generally more saturated and darker in tone.