Diamonds are found in a wide range of colours. However, the overwhelming majority of diamonds used in the jewelery industry are in the white range; which encompasses different shades of brown, gray or yellow.
Body colour of diamonds is rated from “D” which is colourless, to “Z” which is a light yellow that is quite noticeable.
Each letter represents a smaller range of colour. For example, you can have a very light “G” colour diamond and a darker “G” colour diamond with both stones falling under the grade of “G”.
The closer you get to a “D”, the rarer a diamond is. Of course rarity reflects the price. “D” stones are more expensive than a “G” or “Z” stone.
The colour of a diamond can only be graded accurately when the diamond is “loose” (not mounted in a ring).