There are four universally accepted characteristics that all diamonds are graded by. They are known as the 4C's, and they are Cut, Colour, Clarity and Carat weight. It is the combination of these four "C's" that determines a diamond's value. By changing any of the characteristics, you can dramatically affect the diamond's value, all other factors being equal.

The Cut

The cut of a diamond determines its brilliance. There is no single measurement of a diamond that defines its cut, but rather a collection of measurements and observations that determine the relationship between a diamond's light performance, dimensions and finish. Most gemologists consider cut the most important diamond characteristic because even if a diamond has perfect colour and clarity, a diamond with a poor cut will have dulled brilliance.

The width and depth can have an effect on how light travels within the diamond, and how it exits in the form of brilliance.