Stibnite
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| Stibnite | |
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| Missing image Stibnite_Romania.jpg Stibnite from Herja, Romania | |
| General | |
| Category | Mineral |
| Chemical formula | antimony sulfide (Sb2S3) |
| Identification | |
| Colour | Steel gray to dull gray. Black iridiscent tarnish may be present. |
| Crystal habit | Massive, radiationg and elongated crystals. Massive and granular. |
| Crystal system | Orthorhombic |
| Cleavage | Perfect |
| Fracture | Small-scale subconchoidal |
| Mohs Scale hardness | 2 |
| Luster | Splendent on fresh crystals surfaces, otherwise metallic |
| Refractive index | Opaque |
| Pleochroism | N/A |
| Streak | Similar to colour |
| Specific gravity | 4.56 - 4.62 |
| Fusibility | ? |
| Solubility | Souluble in hydrochloric acid |
| Major varieties | |
| Metastibnite | Earthy, reddish deposits |
Stibnite, sometimes also called antimonite, is a sulfide mineral. It crystallizes in the orthorhombic system, has hardness 2 and a grey colour. Its chemical composition is described by the formula Sb2S3
Stibnite is the most important source for the rare metal antimony. It is soluble in hydrochloric acid, and is tarnished by potassium hydroxide solution.
Small deposits of Stibnite are common, large ones 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.
Spectacular, large iridescent stibnite crystals are found in Japan.