color gamut

Developing a comprehensive colored stone grading system has been the dream of gemologists since the late 1970's, but despite a number of valient attempts, we are no closer to the goal today than we were four decades ago. This article examines the various problems of colored stone grading, explaining why the challenges are at least an order of magnitude greater than the grading of diamonds.

Color types such as "pigeon's blood," "cobalt blue" and "Santa Maria" are wildly popular, but also wildly inconsistent.

Color types such as "pigeon's blood," "cobalt blue" and "Santa Maria" are wildly popular, but also wildly inconsistent. Richard Hughes takes a deep dive into the problems of describing color.

Color types such as "pigeon's blood," "cobalt blue" and "Santa Maria" are wildly popular, but also wildly inconsistent.