| Hausmannite | |
|---|---|
 | |
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | MnIIMnIII2O4, MnO·Mn2O3, or Mn3O4 |
| IMA symbol | Hsm[1] |
| Strunz classification | 4.BB.10 |
| Crystal system | Tetragonal |
| Crystal class | Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m) |
| Space group | I41/amd |
| Unit cell | a = 5.76 Å c = 9.46 Å; Z = 4 |
| Identification | |
| Formula mass | 228.81 g/mol |
| Color | Brownish black, grayish. |
| Crystal habit | Massive – granular – common texture observed in granite and other igneous rock. pseudo octahedral – crystals show an octahedral outline. |
| Twinning | Repeated twins on {112} |
| Cleavage | [001] Perfect |
| Fracture | Uneven – flat surfaces (not cleavage) fractured in an uneven pattern. |
| Tenacity | Brittle |
| Mohs scale hardness | 5.5 |
| Luster | Submetallic |
| Streak | Dark reddish brown |
| Diaphaneity | Opaque, transparent on thin edges |
| Specific gravity | 4.7 – 4.84, average = 4.76 |
| Optical properties | Uniaxial (−) |
| Refractive index | nε = 2.15, nω = 2.46 |
| Birefringence | δ = 0.31 |
| Other characteristics | Anisotropism: Distinct, bireflectance: weak; O = light gray; E = dark gray. |
| References | [2][3][4] |
Hausmannite is a complex oxide, or a mixed oxide, of manganese containing both di- and tri-valent manganese. Its chemical formula can be represented as MnIIMnIII2O4, or more simply noted as MnO·Mn2O3, or Mn3O4, as commonly done for magnetite (Fe3O4), the corresponding iron oxide. It belongs to the spinel group and forms tetragonal crystals. Hausmannite is a brown to black metallic mineral with Mohs hardness of 5.5 and a specific gravity of 4.8.
The type locality is Oehrenstock (Öhrenstock), Ilmenau, Thuringian Forest, Thuringia, Germany, where it was first described in 1813.[3] Locations include Batesville, Arkansas, US; Ilfeld, Germany; Langban, Sweden; and the Ural Mountains, Russia.[2] High quality samples have been found in South Africa and Namibia where it is associated with other manganese oxides, pyrolusite and psilomelane and the iron-manganese mineral bixbyite. Wilhelm Haidinger (1827) named it in honour of Johann Friedrich Ludwig Hausmann (1782–1859), Professor of Mineralogy, University of Göttingen, Germany.[3]
Image gallery
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Crystal structure of hausmannite -
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Ettringite crystal on a matrix of hausmannite and hematite, coated by oyelite
References
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Hausmannite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 2 July 2022.
- ^ a b c Hausmannite, Mindat.org, retrieved 2 July 2022
- ^ Barthelmy, David (2014). "Hausmannite Mineral Data". Webmineral.com. Retrieved 2 July 2022.
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This page was last edited on 10 January 2024, at 01:07