malachite

A bright green mineral, a basic copper carbonate, Cu₂CO₃(OH)₂; one of the principal ores of copper.

Although there are dozens of different types of gems, among the best known and most important are […] . (Common gem materials not addressed in this article include amber, amethyst, chalcedony, garnet, lazurite, malachite, opals, peridot, rhodonite, spinel, tourmaline, turquoise and zircon.)

A mild green color, like that of the mineral.

Of a color ranging from olive-taupe to a mild to deeply-rich (at times seemingly translucent) green, like that of the mineral which is present on oxidized copper.