A diamond is one of the best-known and most sought-after gemstones. Diamonds have been known to mankind and used as decorative items since ancient times; some of the earliest references can be traced to India.
The hardness of diamond and its high dispersion of light – giving the diamond its characteristic "fire" – make it useful for industrial applications and desirable as jewelry. Diamonds are such a highly traded commodity that multiple organizations have been created for grading and certifying them based on the four Cs, which are color, cut, clarity, and carat. Other characteristics, such as presence or lack of fluorescence, also affect the desirability and thus the value of a diamond used for jewelry.
In the 1940s, GIA established the “4Cs” and the International Diamond Grading System™ – to this day, the worldwide standard for evaluating diamond quality.
Diamonds in the D-to-Z color range are valued by how closely they approach colorlessness – the less color, the higher their value.