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.
| 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 |
| Luster | Vitreous |
| Streak | pale yellow, white |
| Specific gravity | 4.87 (calculated) |
| Other characteristics | Non-radioactive. |
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 .
![{\displaystyle {\ce {PbGa3 [(AsO4),(SO4)]2 (OH)6}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/ec4750fd7dc9753203796194063b01572eac3c5f)
References
edit- ^ a b Jambor John L, Owens Dealton R, Grice Joel D, Feinglos Mark N (December 1996). "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.
- ^ 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, retrieved 2022-05-23
- ^ "Gallobeudantite".
- ^ "Geology and mineralogy of the Apex germanium-gallium mine, Washington County, Utah". 1986. doi:10.3133/b1577.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Mills, S. J.; Kampf, A. R.; Raudsepp, M.; Christy, A. G. (2009). "The crystal structure of Ga-rich plumbogummite from Tsumeb, Namibia". Mineralogical Magazine. 73 (5): 837–845. Bibcode:2009MinM...73..837M. doi:10.1180/minmag.2009.073.5.837. hdl:1885/53552. ISSN 0026-461X. S2CID 96100676.
- ^ "Gallobeudantite Mineral Data".