Sphalerite : Mock lead

Sphalerite is a mineral ore that is the chief source of zinc. It consists largely of zinc sulfide[?] in crystalline form but often contains some iron. Sphalerite has been called by miners mock lead, false galena, and black-jack. Its color is usually yellow, brown, or black, and its luster resinous. Spahalerite is also a a general term for some minerals, chiefly metallic sulfides which have a somewhat brilliant but nonmetallic luster.