Chemistry:Gallobeudantite
| Gallobeudantite | |
|---|---|
| General | |
| Category | Arsenate minerals |
| Formula (repeating unit) | PbGa3(AsO4)(SO4)(OH)6 |
| Crystal class | 3m - Ditrigonal Pyramidal |
| Unit cell | a = 7.225(4) Å, c = 17.03(2) Å |
| Identification | |
| Color | Pale yellow, greenish, or cream-colored |
| Crystal habit | Trigonal |
| Cleavage | Distinct/Good |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| |re|er}} | Vitreous |
| Streak | pale yellow, white |
| Specific gravity | 4.87 (calculated) |
| Other characteristics | Non-radioactive. |
Gallobeudantite is a secondary, Gallium-bearing mineral of beudantite, where the Iron is replaced with Gallium, a rare-earth metal. It was first described as a distinct mineral by Jambor et al in 1996.[1] Specific Gallium minerals are generally rare and Gallium itself is usually obtained as a by-product during the processing of the ores of other metals. In particular, the main source material for Gallium is bauxite, a key ore of aluminium. However, Gallobeudantite is too rare[2] to be of economic value. Its main interest is academic and also among mineral collectors.
Jambor et al.[1] describes Gallobeudantite as having occurred as zoned rhombohedra, up to 200 μm along an edge, in vugs in a single specimen of massive Cu-bearing sulfides from Tsumeb, Namibia. Gallobeudantite can be pale yellow, greenish, or cream-colored and has a white to pale yellow streak.[3] It has a vitreous luster.
Since the discovery of Gallobeudantite, there has been renewed interest in this class of mineral, particularly in the famous Apex deposit in Utah[4] and additional studies on the crystal structure of Ga-rich plumbogummite from Tsumeb[5]
The mineral has only been found so far in the Namibian Tsumeb Mine, located in the Oshikoto Region.[6] The mineral is a mixture of three elements Gallium, Arsenic and Lead with the formula [math]\ce{ PbGa3 [(AsO4),(SO4)]2 (OH)6 }[/math].
References
- ↑ 1.0 1.1 "Gallobeudantite, PbGa 3 [(AsO 4 ),(SO 4 ) 2 (OH) 6 , a new mineral species from Tsumeb, Namibia, and associated new gallium analogues of the alunite-jarosite family"]. The Canadian Mineralogist 34 (6): 1305–1315. December 1996. https://pubs.geoscienceworld.org/canmin/article-abstract/34/6/1305/12829/Gallobeudantite-PbGa-3-AsO-4-SO-4-2-OH-6-a-new.
- ↑ Dutrizac, John E.; Jambor, John L. (2001-12-31), "8. Jarosites and Their Application in Hydrometallurgy", Sulfate Minerals (De Gruyter): pp. 405–452, doi:10.1515/9781501508660-010, ISBN 9781501508660, http://dx.doi.org/10.1515/9781501508660-010, retrieved 2022-05-23
- ↑ "Gallobeudantite". https://www.mindat.org/min-6962.html.
- ↑ Geology and mineralogy of the Apex germanium-gallium mine, Washington County, Utah. 1986. doi:10.3133/b1577.
- ↑ Mills, S. J.; Kampf, A. R.; Raudsepp, M.; Christy, A. G. (2009). "The crystal structure of Ga-rich plumbogummite from Tsumeb, Namibia" (in en). Mineralogical Magazine 73 (5): 837–845. doi:10.1180/minmag.2009.073.5.837. ISSN 0026-461X. Bibcode: 2009MinM...73..837M. https://www.cambridge.org/core/journals/mineralogical-magazine/article/abs/crystal-structure-of-garich-plumbogummite-from-tsumeb-namibia/8E62C7DF5C9E6A7BE7E1A93A51F82710.
- ↑ "Gallobeudantite Mineral Data". http://webmineral.com/data/Gallobeudantite.shtml#.Yoq006jMKUk.
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