The Gemmological Institute of America (GIA) created the Diamond Colour Scale in the 1950s to give definition to the colour spectrum of diamonds. The scale starts at D and continues through to Z becoming progressively more yellow towards the end of the alphabet.
The most valuable and rare colour is white, that is to say, colourless. diamonds will display subtle coloured tones. Diamonds with a very strong and distinct colour are extremely rare and are called fancies.
Diamonds in this range are colourless, very rare and demand premium prices. They are regarded as 'collection' colours because of their scarcity and amazing whiteness. The unaided and untrained eye would find it extremely difficult to distinguish between these three grades.
This range is classed as near-colourless, G and H being the more desirable and termed as 'rare white diamonds'. The whole group represent very good value. Our advice would be to buy H and above if possible unless price or carat weight demand otherwise.
K to Z
These grades display visible signs of yellow colour and whilst they are excellent in brooches and alternative jewellery are not in demand for the diamond solitaire engagement ring and similar settings.