: Unlike many commodities, emerald value increases exponentially rather than linearly with size. For example, a high-quality 5-carat emerald can cost 10 to 20 times more than a 1-carat stone of identical quality.
The conversion of an emerald into a specific monetary value depends on four primary physical attributes: Emeralds to Money
A stone's origin acts as a "brand" that dictates its baseline market value. Global Emerald Market Economics - Gem Resources : Unlike many commodities