smithsonite

An unusual specimen comprising both solid botryoidal aggregates and hollow, sub-spherical "shells" (to 8 mm) of microcrystalline smithsonite on a matrix of iron stained dolostone.  The smithsonite varies in colour from yellow, through orange-pink to pinkish-brown with sparse microcrystals of cerussite on the smithsonite surfaces.

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). The Co content (43 ppm) is believed to be too low to act as a chromophore, so the unusual "salmon-pink" colour may be due to the presence of Mn (1943 ppm) perhaps supplemented by partial oxidation of Fe (7420 ppm) in solid solution in the smithsonite. Analytical data is presented in Exhibit 2.

dolomite