Colour
The colour of a diamond is defined as the "natural visible body colour". The most prized diamonds are actually colourless, because their beauty then depends entirely upon the reflective and refractive properties of that gem. In such diamonds, all the colours of the rainbow are reflected back to the eye. This is called "fire" or "dispersion", and should not be confused with the body "colour" of the diamond. (See the 4th "C"... Cut... for a detailed description of optical properties)
In diamonds, gemologists grade against the colour yellow. Each diamond is placed upside down on a white background and viewed perpendicular to the pavillion (bottom) of the gem. Several scales of colour are used in the industry, the most common being the GIA standard. GIA uses the alphabet ... "D" being perfect.
D E F are virtually colourless demanding the highest price.
G H I are near colourless.
J K L M are slight yellow.
N O P Q R are very light yellow, and so on.
The difference between each letter grade is very subtle. Gemologists never try to remember colour, they generally compare each diamond to their Colour Master Set where the colours are certain.
Gemologists also take other factors such as ultra violet light and fluorescence into consideration before assessing a diamond's final colour grade. You can trust the Gemologists at Wharram's Jewellery that the colour grade is the true natural colour of that diamond.
