Colour

The colour within the "Colour" criterion of the 4Cs is indicated on a scale from D to Z. The earlier in the alphabet the colour rating is, the more valuable the diamond, which should be as "colourless" as possible (D-F). However, the colour rating does not apply to coloured stones, known as fancy colour diamonds. These are even intended to have a colour. Fancy diamonds can be produced in many different colours, from light pink to black.