Even among that group, however, there's a difference of opinion about what's considered "too light." GIA uses lab-graded comparison stones to determine if the green color is dark enough and saturated ...
A rare square 37-carat emerald owned by the Aga Khan fetched nearly $9 million at auction in Geneva on Tuesday, making it the world's most expensive green stone. Sold by Christie's, the Cartier ...
The varying presence of these three elements gives emerald its range of color. Chromium and vanadium make an intense green color. Iron gives the stone a bluish tint. The most valuable emeralds are ...