But, for those considering purchasing Emeralds of investment quality, here are some important factors. The most important determiner of the price of an Emerald is its color. Following this, the stone's clarity, carat weight, and the amount and type of inclusions are the other major determinants of value. Dark, clear stones with few or no visible inclusions command prices higher than those of equally fine diamonds.
Colombian goldsmiths use
only 18kt gold (or purer) when working with Emeralds, and take special
care to protect the gems from heat while setting them. Bezelled settings
are recommended, as they provide all-around protection to the stone.
Bezelling also allows jewelers to place quality stones of slightly
less color in a setting which darkens the stone's hue while amplifying
its green fire. Finally, most Colombian Emeralds are "oiled,"
a process by which palm oil, or a similar oil, is applied under pressure
(about 700 pounds per square inch) to fill the minute inclusion voids
in the gems, thereby optimizing the aesthetic beauty of the stone.