Diamonds occur in many different colours, from pink through to brown, orange and blue. However, most diamonds of gem quality appear on a scale from colourless to yellow. The most intensely coloured diamonds are called ‘fancy’ and there’s an increasing market for them. Colourless diamonds have traditionally been popular, especially for engagement rings and the fewer the flaws within the diamond, the more precious the gem.

Diamonds are rated on a special scale, under magnification so that any internal flaws can be seen. Completely colourless diamonds are the rarest and most expensive - diamonds with flaws become more affordable as the number of flaws increase.