Colour

The colours of diamonds are graded on a scale using the letters of the alphabet from D to Z, with D being described as "colourless" or "exceptionally white". Diamonds further down the colour scale will increasingly appear more dull and yellow in colour.

The rarest and therefore the most expensive diamonds are those in the range D-E (Colourless/Exceptionally White), followed by F-G (Rare White) and then H (White).