4 Cs

Last reviewed · June 2026

4 Cs. The four properties that determine a diamond's value on the resale market: cut, color, clarity, and carat weight. Professional buyers grade every diamond on these four scales before pricing it, whether or not a grading report is provided.

The 4 Cs were standardized by the Gemological Institute of America in the 1940s and are now the universal language used by buyers, sellers, and grading labs worldwide.

On the resale side, the 4 Cs determine the wholesale baseline of an offer. Two of the four — cut and color — have the strongest influence on perceived beauty and therefore on demand from the next buyer in the chain.

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