Emerald – Natural, Faceted, Green

"Emerald" is both a gemstone and a term for a shade of green. How can gemologists tell if an emerald-colored gemstone is actually an emerald gemstone? The Mackay Emerald, on display at the Smithsonian Institution. Photo by greyloch. Licensed under CC By-SA 2.0.

Article: What are Gemstone Absorption Spectra?

Credit: greyloch