The colour of the diamond is determined by the different gasses present during the crystallization process. In general, diamond colours range from white to yellow. In rare instances different gasses present with the crystallization process integrates into the diamond generating unique colours such as blue, green, pink, and red.

Diamonds are graded according to their inherent colour using a white to yellow colour scale from D to Z.

D to F represent colourless stones and are usually favoured for investment purposes due to higher premiums. G to J represent near-colourless stones but are as appealing as the complete colourless gem. K to Z becomes more yellow to the naked eye and therefore more cost effective as the colour scale moves down, although at present, yellow stones have become a lot more popular and fashionable.