The diamond colour scale was devised by the Gemological Institute of America (GIA) in the mid 1950's to define and regulate the colour spectrum of diamonds. The GIA proposed starting at D as the best and most colourless diamond available. The colour D was chosen because diamond dealers were already using A, B and C and a break was required to regulate and harmonize the industry. The diamond colour scale progresses through the alphabet from D until Z. The graphic below illustrates the GIA colour scale.
GIA Colour Grading Scale
Diamonds that are colourless, D, E or F are very rare and with a very limited supply they demand premium prices. Less than 1% of all diamonds are colourless and so the market demands a premium because of the scarcity. The diamond colours D, E or F are regarded as the 'collection colours' because they are so scarce and fantastically white. For the untrained and unaided eye, it is very difficult to distinguish between D, E or F colours as they are all colourless with miniscule difference in colour.
Diamonds that are colours G, H, I, or J are classified near-colourless and represent very good value. G and H are the more saught after in this particular near-colourless group and are also termed 'rare white diamonds'. Diamonds in I and J colours are slightly warmer and do command a reduction in price. DiamondGeezer.com would recommend clients buy H and above and drop below this colour grade only if price or carat size is the principle criteria. In saying that there is occasions when slight to medium fluorescence can interact with natural ultra violet light and bring a warmer diamond up a colour grade so this combination is worthy of further investigation, [see our section on diamond fluorescence].
A white gold or platinum setting will show up a diamond's colour as these metals are very white. Because gold is naturally yellow, yellow gold will make a colourless diamond appear more yellow. The use of a yellow gold bezel style setting can help a ‘warmer’ diamond appear a grade or two higher and can be considered if yellow gold is preferred, [see our section on diamond jewellery].
Colour grades of K to Z show visible signs of yellow colour and are not in demand. These colours are viewed as being poorer quality and there is less demand by the industry and consumers which is a little hard on these natural diamonds. Colours K to Z are fantastic in dress rings, brooches and alternative jewellery but the single solitaire engagement ring demands a better, whiter coloured diamond. It is the generally agreed conception that they are not as beautiful as colourless diamonds until they reach a point where the colour becomes so evident they become beautiful ‘fancy colours’ which have very high values (Z+ or Fancy). Beauty is in the eye of the beholder and colour choice is ultimately a personal preference with different cultures, socioeconomic groups and nationalities having different requirements. Even the light yellow diamonds from N to Z are still nature's miracles that have taken millions of years to crystallise and will always be preferable and have more kudos than a man made synthetic gem stone.
In summary the colour spectrum of diamonds starts at D and ends at Z and then into the fancy colours. The most expensive 'white diamonds' are the colourless diamonds D, E or F and then the near-colourless G, H, I, or J with G and H being universally most popular. The spectrum then gets a visible yellow hue from K-Z and the price becomes cheaper as these diamonds are more readily available.