smithsonite

Intergrown crystals of rhombohedral smithsonite (to 7 mm) lining vugs and voids in a matrix of galena-rich massive sulphide. The smithsonite is highly translucent and smaller crystals appear almost colourless, while larger crystals and intergrowths present with a weak buff to brown colour.

The specimen was purchased from Australian collector George Stacey in 2007, but with no record of its earlier provenance.

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). Analytical data is presented in Exhibit 2. Most of the smithsonite on this specimen is essentially colourless, although Co (90 ppm) and Mn (1103 ppm) are both close to the thresholds expected to influence color. A weak tan-color is evident in the cores of some of the smithsonite crystals, probably due to Fe oxides, either as localised inclusions or from partial oxidation of Fe (13095 ppm) in solid solution in the smithsonite.

galena