scheelite

scheelite (shāˈlĪt, shēˈ–) [key], heavy white or yellow mineral, calcium tungstate, CaWO₄, crystallizing in the tetragonal system. It is found in granite pegmatites, in contact-metamorphic deposits (especially limestones intruded by granites), and in quartz veins. It is an important ore of tungsten and is mined in many parts of the world. Scheelite fluoresces bright bluish-white in ultraviolet radiation, a distinguishing feature utilized in prospecting and mining.