mathewrogersite

According to Gebhard (1999) the discovery of mathewrogersite, IMA 1984-042, is credited to TCL mineralogist John Innes. The mineral was described by Keller and Dunn (1986) and named for mining engineer Mathew Rogers, who led the first expedition of the South West Africa Company to Tsumeb in 1892 (Söhnge 1967). Type material is conserved at the Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Germany (catalogue numbers TM-84.42 and TL-8904.01).

Mathewrogersite forms sub-parallel intergrowths of flattened six-sided crystals (to 0.3 mm), with possible rhombohedral faces and radiating aggregates of scales and blades (to 1 mm diameter). The crystals range from colourless to white, yellowish or greenish.

Keller and Dunn (1986) described two specimens of mathewrogersite in their original characterisation of the mineral. The location from which the first specimen was recovered is unknown (although its paragenesis indicates that it is certainly from the second oxidation zone); on this specimen mathewrogersite is associated with anglesite, kegelite, leadhillite and schaurteite on a matrix of chalcocite, hematite and quartz.

The second specimen was collected from the East 9 Pillar on 31 Level and comprises hemispherical aggregates of mathewrogersite (to 1 mm), pale greenish-yellow in colour. These aggregates are associated with alamosite, leadhillite and queitite (all older than the mathewrogersite); melanotekite (which occupies a similar paragenetic position to the mathewrogersite) and younger larsenite, mimetite and willemite.

alamosite; anglesite; chalcocite; hematite; galena; germanite; kegelite; larsenite; leadhillite; melanotekite; mimetite; plumbotsumite; quartz; queitite; schaurteite; sphalerite; surite (?); willemite