Diamond value is based on a combination of features, sometimes called value factors. As with other gemstones, diamonds with certain qualities are more rare — and more valuable — than diamonds that lack them. Without a methodical system to evaluate and discuss these factors, there would be no way to evaluate and compare one diamond to another.
Diamond professionals use a special set of four value factors to classify diamonds: clarity, color, cut, and carat weight, also known as the Four Cs. The combination of these factors describe the overall quality of a finished diamond. Therefore, the combination of the these factors is a major determinant of a diamond value and price.
Each diamond’s value is based on its own unique combination of the Four Cs. Often, a diamond has one value factor that stands out because it’s so rare. For instance, colorless diamonds are scarce—most diamonds have tinge of color, usually brown or yellow. So a colorless diamond has a higher color rating than a diamond with a tinge of yellow. Value and rarity are related: all else equal, a colorless diamond is more rare and more valuable than one with a slight tinge of yellow color. The same is true on the opposite spectrum of diamond color: fancy color diamonds. The stronger and purer the color, whether it’s blue, pink, red, or even strong yellow (as opposed to a tinge of yellow), the rarer the diamond is, and hence, the higher its value. The same relationship between rarity and value also exists for the other value factors.
The Four Cs describe the characteristics of a diamond in very precise terms. They are the international language that professionals can use to describe and evaluate diamonds.
The Four Cs have a long history. Three of them — color, clarity, and carat weight — were the basis for the first diamond grading system established in India over 2,000 years ago. Cut wasn’t important then, since nobody knew how to shape and polish a diamond. However in later times, the art of diamond cutting evolved. As new technology became available, diamond cutters develop new techniques and built new instruments. Today, modern cutting brings out the best luster and sparkle out of a diamond, making diamond cut an important factor in determining a diamond’s value.