The highest quality diamonds are those which are completely colourless. If the diamond has little or no colour, it is easier for light to pass through it, which creates a spectrum of colours. Because colourless diamonds act as perfect prisms they are most sought after for their pure, dazzling beauty.

Diamonds are graded from colourless (the highest quality) to light yellow (low quality). The differences between each grade are very subtle and can be seen more clearly on the following chart.