The market for coloured stones differs wildly to that of its diamond counterpart. Two stones that are identical in dimensions and clarity can be priced with a large difference (the superior stone sometimes many multiples of the price of the lesser stone) due to what may be seen to the untrained eye as a subtle difference in colour. It can best be described as “an art as much as it is a science”.
This aside the 4’cs that are applied to the diamond market also play a major role in emerald grading. Treatment is also an area where emeralds differ due to the unique way in which they are treated. A no treatment stone of equal colour and cut to a stone with minor treatment will command a significant premium.
