stibnite, 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.

Antimony sulfide (Sb₂S₃), the principal ore of antimony. This sulfide mineral has a brilliant metallic lustre, is lead or steel gray in colour, and fuses (melts) readily. Stibnite occurs in low-temperature hydrothermal veins (see hydrothermal ore deposits) and in replacement deposits. Significant deposits have been found in China, Japan, and the U.S. (Idaho, California, and Nevada). Stibnite is used in making matches, fireworks, and percussion caps and was used by the ancients as a cosmetic (called kohl) to increase the apparent size of the eye.

Learn more about stibnite with a free trial on Britannica.com.

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.

Formation, structure, reactivity

Sb₂S₃ forms when antimony(III) compounds are treated with hydrogen sulfide. This reaction gives a black precipitate:

2 Sb³⁺ + 3 H₂S → Sb₂S₃ + 6 H⁺

This reaction is reversed by hydrochloric acid.

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.

Uses

Stibnite has no significant uses, except as a precursor to antimony oxide, which is the most commonly marketed form of antimony. In ancient times, it was used as mascara called kohl.

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.

Occurrence

Small deposits of stibnite are common, but large deposits are rare. It occurs in Canada, Mexico, Peru, Japan, China, Germany, Romania, Italy, France, England, Algeria, and Kalimantan, Borneo. In the United States it is found in Arkansas, Idaho, Nevada, California, and Alaska. Large iridescent stibnite crystals are found in Japan.

As of May 2007, the largest specimen on public display (1000 pounds) is at the American Museum of Natural History.

See also

• List of minerals

References