| Gallobeudantite | |
|---|---|
| General | |
| Category | Arsenate minerals |
| Formula | 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. |
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 .
