colour

The colour of a precious and semi precious stone would be affected mainly by the influences of heat and presence of other bodies and elements as a stone is formed. If a raw stone is formed in the ground close to pockets of oxides or other minerals then the stone formation may be slightly different. A perfect example would be the introduction of iron to corundum causing it to turn blue into a sapphire or chromium to turn it red into a ruby.

Why is colour so important?

Apart from the obvious visual aspect of colour in a diamond, the presence of colour in a diamond crystal would dampen and obstruct the journey of light. The best stones to transport light would be colourless. The stone's fire, flourescence and brilliance would also be affected by colour. Coulored stones may seem dull in comparison or have different effects under different light sources.

The standard chart for diamonds are for the white to yellow grades, however diamonds are found in other colours, or can be treated to synthesize a different colour. These are called FANCY COLOURS, and can be found in pink, blue, green, black and brown and various other colours of a diamonds spectrum. If a stone has been treated to alter it's colour would normally be noted in the diamond grade certification. A Diamond colour grade would be represented by a single letter ie J, at times if the grader is unsatisfied the stone may be described as ie : J / K meaning it is inbetween the two classes of colour

Below images are only a basic simulation of the diamond colour grades and not intended to be perfectly acurate.