Nature dictates the characteristics of color, clarity and carat, while cut is directly influenced by humans. Although the 4Cs provide scientific guidelines for evaluating diamond quality, they do not necessarily measure diamond beauty.

COLOR

Most diamonds appear icy white, but many have tiny hints of color. Diamonds are graded on a color scale established by the Gemological Institute of America (GIA), ranging from D (colorless) to Z.

Colorless diamonds are extremely rare, and therefore very valuable. But there are no hard and fast rules for what color makes a diamond beautiful. The Incomparable, one of the world's most beautiful diamonds, contains hints of brown, smokey amber and champagne colors.

One carat (not to be confused with Karat;the measure of purity of gold) is the equivalent of 200 milligrams. One carat can also be divided into 100 "points." A .75 carat diamond is the same as a 75-points or a 3/4 carat diamond.

The term carat is a derivative of the word carob. Carob seeds, which are surprisingly uniform in weight, were used as a reference for diamond weight in ancient civilizations. One carob seed equaled one carat.

It is often assumed that a 1-carat diamond costs exactly twice the price of a 1/2-carat diamond. This is not the case. Since larger diamonds are found less frequently in nature, a 1-carat diamond will cost much more than twice as much as a 1/2-carat diamond, assuming color, clarity and cut remain constant.

CLARITY

The position of inclusions can affect the value of a diamond. You may not notice a significant difference between an SI 1 and a SI 2. However, you should consider the number, size, brightness, nature and position of the inclusions.

Some inclusions can be hidden by a mounting, thus having little effect on the beauty of a diamond. An inclusion in the middle or top of a diamond, however, could impact the dispersion of light, sometimes making the diamond less brilliant.