Stibnite, sometimes called antimonite, is a sulfide mineral with the formula Sb2S3. This soft grey material crystallizes in an orthorhombic space group. It is the most important source for the metaloid antimony. The abbreviation for antimony, Sb, is taken from stibnite.
Stibnite is attacked by potassium hydroxide solution and dissolves in solutions of polysulfide ions to give polysulfido complexes. Related reactions were once used in university courses on qualitative inorganic analysis.
Stibnite has a structure similar to that of arsenic trisulfide, As2S3. The Sb(III) centers, which are pyramidal and three-coordinate, are linked via bent two-coordinate sulfide ions.
Antimony trisulfide finds use in pyrotechnic compositions, namely in the glitter and fountain mixtures. Needle-like crystals, "Chinese Needle", are used in glitter compositions and white pyrotechnic stars. The "Dark Pyro" version is used in flash powders to increase their sensitivity and sharpen their report. It is also a component of modern safety matches. It was formerly used in flash compositions, but its use was abandoned due to toxicity and sensitivity to static electricity.
As of May 2007, the largest specimen on public display (1000 pounds) is at the American Museum of Natural History.