The market for pink diamonds is somewhat separate to that of white diamonds, and due to their rarity, pink diamonds typically command prices far in excess of their white counterparts. As a general “rule of thumb” pink diamonds of a similar size and quality will be 25-35 times the price of a white diamond.
There are three important factors to understanding the colour of pink diamonds: hue, tone and saturation.
Hue is the dominant colour of the diamond; tone is the amount of light or darkness in the diamond; and saturation is the strength of hue. The more intense and saturated the colour, the rarer and more valuable the diamond.
For fancy coloured diamonds, the 'C' for colour is typically more important the other three 'Cs' of clarity, cut and carat weight when it comes to grading and value.
The presence of colour in pink diamonds remains a mystery, but it is certain that it is not derived from a predominant trace element or impurity as is the case with some other colours such as blue or yellow diamonds. In the case of Argyle pink diamonds, it is thought that extraordinary pressure and temperature more than 160 kilometres below ground raised the diamonds to the surface and it has been established that there is an altered crystal lattice in pink diamonds which when refracting light produces in the pink, purple and red spectrum.