scheelite

views updated May 08 2018

scheelite Mineral, CaWO4; sp. gr. 5.9–6.1; hardness 4.5–5.0; tetragonal; white, or sometimes shades of yellow, green, brown, or red; white streak; vitreous lustre; crystals usually bipyramidal, also occurs massive or granular; cleavage good {111}; fluorescent; occurs in pegmatite veins and high-temperature mineral veins, often in association with wolframite, cassiterite, molybdenite, fluorite, and topaz, also in contact metamorphic zones together with axinite, garnet, wollastonite, and metamorphic calcium minerals. It is one of the chief ores of tungsten, and named after the 18th-century Swedish chemist K. W. Scheele.