Four Factors – known as the Four Cs affect the value of every diamond:
- Carat Weight
A stone’s relative position on a flawless-to-imperfect scale. Clarity characteristics are classified as inclusions (internal) or blemishes (external). The size, number, position, nature, and color or relief of characteristics determine the clarity grade. Very few diamonds are flawless, that is, show no inclusions or blemishes when examined by a skilled grader under 10x magnification. If other factors are equal, flawless stones are most expensive.
Grading color in the normal range involves deciding how closely a stone’s body color approaches colorlessness. Most diamonds have at least a trace of yellow, brown, or body color. With the exception of some natural fancy colors, such as blue, pink, purple, or red, the colorless grade is the most valuable.
The proportions and finish of a finish of a polished diamond (also called make). Cut can also meanshape, as in emerald cut or marquise cut. The Proportions are the size and angle relationships between the facets and different parts of the stone. Finish includes polish and details of facet shape and placement. Cut affects both the weight yield from rough and the optical efficiency of the polished stone; the more successful the cutter is in balancing these considerations, the more valuable the stone will be.
The metric carat, which equals 0.200 gram, is the standard unit of weight for diamonds and most other gems. If other factors are equal, the more a stone weight, the more valuable it will be.