| Stibnite | |
|---|---|
Stibnite in the Carnegie Museum of Natural History |
|
| General | |
| Category | Sulfide mineral |
| Chemical formula | Sb2S3 |
| Strunz classification | 02.DB.05a |
| Crystal symmetry | Orthorhombic dipyramidal H-M symbol: (2/m 2/m 2/m) Space group: Pbnm |
| Unit cell | a = 11.229 Å, b = 11.31 Å, c = 3.8389 Å; Z = 4 |
| Identification | |
| Color | Lead-gray, tarnishing blackish or iridescent; in polished section, white |
| Crystal habit | Massive, radiating and elongated crystals. Massive and granular |
| Crystal system | Orthorhombic |
| Twinning | Rare |
| Cleavage | Perfect and easy on {010}; imperfect on {100} and {110} |
| Fracture | Subconchoidal |
| Tenacity | Highly flexible but not elastic; slightly sectile |
| Mohs scale hardness | 2 |
| Luster | Splendent on fresh crystals surfaces, otherwise metallic |
| Streak | Similar to color |
| Diaphaneity | Opaque |
| Specific gravity | 4.63 |
| Solubility | decomposed with hydrochloric acid |
| Other characteristics | Anisotropism: Strong |
| References | [1][2][3] |
| Major varieties | |
| Metastibnite | Earthy, reddish deposits |
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 metalloid antimony.[4] The name is from the Greek stibi through the Latin stibium as the old name for the mineral and the element antimony.[1][2]
Contents |
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. It is grey when fresh, but can turn superficially black due to oxidation in air.
Pastes of Sb2S3 powder in fat[5] or in other materials have been used since 3000 BC as eye cosmetics in the Middle East and farther afield; in this use, Sb2S3 is called kohl. It was used to darken the brows and lashes, or to draw a line around the perimeter of the eye.
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.[6]
The natural sulfide of antimony, stibnite, was known and used in Biblical times, as a medication and in Islamic/pre-Islamic times as a cosmetic. The Sunan Abi Dawood reports, “prophet Muhammad said: 'Among the best types of collyrium is antimony (ithmid) for it clears the vision and makes the hair sprout.'”[7]
Stibnite occurs in hydrothermal deposits and is associated with realgar, orpiment, cinnabar, galena, pyrite, marcasite, arsenopyrite, cervantite, stibiconite, calcite, ankerite, barite and chalcedony.[1]
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.
As of May 2007, the largest specimen on public display (1000 pounds) is at the American Museum of Natural History.[8][9] The largest documented single crystals of stibnite measured ~60×5×5 cm and originated from different locations including Japan, France and Germany.[10]
Chisholm, Hugh, ed (1911). "Stibnite". Encyclopædia Britannica (11th ed.). Cambridge University Press.