stibnite (stĭbˈnĪt) [key], antimony sulfide, Sb2S3, a mineral, silvery gray in color, with a metallic luster. It crystallizes in the orthorhombic system. Found in many parts of the world, it is the most important ore of antimony. It is commonly deposited by alkaline waters and occurs in association with quartz, calcite, sulfides of the base metals, arsenic, gold, and silver. Known in ancient times, stibnite was used in powdered form by women to darken their eyebrows and eyelashes. Antimony is used in alloys for type metal, storage batteries, pewter, babbitt, and antifriction metal for bearings. Its compounds find use in explosives, matches, and fireworks, in vulcanizing rubber, and in medicine as an emetic.