Image Credit: Malcolm Southwood
Image Credit: Malcolm Southwood
Title
smithsonite
Principal Mineral
Size
Cabinet; 132mm
Collection
Geoscience Australia R28842
Provenance
Latz, C.V.
Entry Type
Specimen TSNB512
Description
A thick cast, or zinkschale, of intergrown, platy rhombs of smithsonite. Most of the smithsonite (by volume) is colourless-white, but it appears orange-yellow due to partial oxidation of iron in solid solution at or close to the crystal surfaces (see below). This zincschale appears to have formed lining a cavity in ferruginous, gossan-like material, some of which remains on its outer (convex) surface.
The specimen is from the collection of Clement Victor Latz which was donated to the Australian Bureau of Mineral Resources (now Geoscience Australia) in 1976.
The specimen has been analysed by EMPA-WDS and LA-ICP-MS as part of a study of the causes of colour in smithsonite (Weall 2023; Southwood et al. 2025). They hypothesised that while the Fe content is relatively low (1591 ppm) the yellow colouration is due to partial oxidation of ferrous iron in solid solution in the smithsonite. Cd (554 ppm) and S (95 ppm) are present at low concentrations but there is no evidence for inclusions of either Fe oxides or CdS in the smithsonite crystals. Analytical data is presented in Exhibit 2.
Associated Minerals
goethite (?)
