Green Diamonds

Natural green diamonds are amongst some of the rarest and most valuable of all fancy coloured diamonds. The gem's value depends on the hue and intensity of the colour with the range of known greens including emerald, bottle and grass.

Green diamonds are formed by radiation: the raw diamond has at some point come into contact with radioactive material, for example uranium ore. The natural irradiation takes a long time and many mined diamonds have only small spots of green which are considered blemishes and cut out.

The colouring process can sometimes be repeated artificially, using irradiation and heat treatment to "enhance" ordinary diamonds and give them a green colour. These enhanced green diamonds are more affordable than natural colour stones but still remain rare. Natural diamonds with a light green hue are sometimes also irradiated to deepen the colour.

The most famous natural green in the world is the Dresden Green. This stone weighs 40.7 carats (8.2 grams) and is classified as being "apple green".