Chemistry:Daubréeite
| Daubréeite | |
|---|---|
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | BiO(OH,Cl) |
| Strunz classification | 3.DC.25 |
| Crystal system | Tetragonal |
| Crystal class | Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m) |
| Space group | P4/nmm |
| Unit cell | a = 3.85, c = 7.4 [Å]; Z = 2 |
| Identification | |
| Color | Creamy-white, grayish, yellowish-brown |
| Crystal habit | Compact massive, columnar |
| Cleavage | [{001}, perfect |
| Tenacity | Very plastic, sectile |
| Mohs scale hardness | 2-2.5 |
| |re|er}} | Greasy, silky |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 6-6.5 |
| Optical properties | Uniaxial (-) |
| Refractive index | nω = 2.150 nε = 1.910 |
| Birefringence | δ = 0.240 |
| References | [1][2][3] |
Daubréeite is a rare bismuth oxohalide mineral with formula BiO(OH,Cl). It is a creamy-white to yellow-brown, soft, earthy clay–like mineral which crystallizes in the tetragonal crystal system. It is a member of the matlockite group.[1]
It was first described for an occurrence in the Constanicia mine, Tazna, Bolivia, in 1876.[5] It was named for French mineralogist Gabriel Auguste Daubrée (1814–1896).[1] At the Tanza location it occurs as a secondary mineral formed by the oxidation of native bismuth or bismuthinite. It occurs with clay minerals.[3] In addition to its discovery location it has also been reported from the Tintic District in the East Tintic Mountains of Juab County, Utah; in the Josephine Creek District of Josephine County, Oregon; in the Manhattan District of Nye County, Nevada; and the Rio Marina Mine on Elba, Italy.[1]
References
- ↑ 1.0 1.1 1.2 1.3 Daubréeite on Mindat
- ↑ Daubréeite on Webmineral
- ↑ 3.0 3.1 Daubréeite in the Handbook of Mineralogy
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ Domeyko (1876). "Daubréite(oxychlorure de bismuth), espèce minérale nouvelle". Comptes Rendus de l'Académie des Sciences de Paris 82: 922–923. http://gallica.bnf.fr/ark:/12148/bpt6k30396/f918.image.
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