Mounted diamonds cannot, but their weights can be calculated from careful measurements. As the carat weight of the diamond increases, so does its rarity and therefore its price. Even though two diamonds may be of the same size, they can still have different values because of their color, clarity or cut. Diamonds actually come in all types of colors, however the most sought after type is said to have fine color , or little to no visible color at all. Naturally colored diamonds are described as having fancy color .
Most diamonds are slightly yellow or brown, and are graded by how closely they approach colorless.
The less color, the higher the value. With fancy colors, however, the grade and value increase with the color intensity. Truely colorless stones are graded D, and are graded up the alphabet from there according to color. Clarity refers to the presence of internal features such as breaks or foreign bodies, called inclusions , which occur inside the diamond. It also refers to blemishes which are external imperfections such as scratches.