Color refers to the uniform color. The more vivid and saturated through out the stone it determines a higher value.
Clarity refers to the absence of defects.
Cut refers to the portions and symmetry of the gemstone. A well-cut gemstone is symmetrical. The cut affects the intensity of the gemstone color.
Carat refers to the weight of the gemstone.
DID YOU KNOW? The word carat comes from the carob seed, the original unit of measure for gem traders. Carat weight is unrelated to the similar sounding karat, which refers to gold's purity.