| Montbrayite | |
|---|---|
 Montbrayite (Montbray, Quebec) | |
| General | |
| Category | Sulfosalt minerals |
| Formula (repeating unit) | (Au,Ag,Sb,Bi,Pb)23(Te,Sb,Bi,Pb)38 or (Au,Sb)2Te3[1] |
| IMA symbol | Mnb[1] |
| Strunz classification | 2.DB.20[2] |
| Crystal system | Triclinic |
| Crystal class | Plumbo-telluride |
| Identification | |
| Color | cream, yellowish white,[3] very light yellow[1] |
| Crystal habit | small segregations, rarely exceeding 3-5 mm, crystals very rare |
| Twinning | observed |
| Cleavage | very good {110}, {011}, {111} |
| Fracture | irregular to uneven, sub-conchoidal, the mineral is very fragile |
| Tenacity | very brittle |
| Mohs scale hardness | 2.5 |
| Luster | metallic[1] |
| Diaphaneity | opaque[3] |
| Density | 9.94 (measured) |
| Pleochroism | very weak[3] |
Montbrayite (from a Canadian toponym) is a very rare mineral from among the gold tellurides, close to krennerite and calaverite, in composition it is a mixed polymetallic plumbo-telluride of gold with a variable formula, initially written as Au2Te3,[4]: 20–21 or (Au,Sb)2Te3,[1] but today having a much more complex form in the calculated form: (Au,Ag,Sb,Bi,Pb)23(Te,Sb,Bi,Pb)38. The color of montbrayite is cream, tin-white to pale yellow, the luster is metallic.
- ^ a b c d e Montbrayite (A valid IMA mineral species, grandfathered): information about the mineral montbrayite in the Mindat database.
- ^ Montbrayite on the website Mineralienatlas (in German)
- ^ a b c John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Hrsg.): Handbook of Mineralogy, Mineralogical Society of America. 2001. — Montbrayite.
- ^ O. M. Shubnikova. New mineral species and varieties discovered in 1945-1949. Proceedings of the Institute of Geological Sciences. Issue 144, mineralogical and geochemical series (No. 16). — Moscow: USSR Academy of Sciences Publishing House, 1953. — 155 p. (in Russian)