tsumcorite

A siliceous matrix, with well-formed quartz crystals (to 6 mm) on the display face, mostly flat-lying, and almost completely encrusted with chocolate-brown goethite (?). An extensive but incomplete crust of orange-yellow tsumcorite completes the paragenesis, providing a striking colour contrast against the underlying goethite. The tsumcorite comprises sheaves of acicular crystals (to circa 2 mm; exhibits 2 and 3).

The specimen was acquired froom Swiss collector Hans Thoni.

The location in the mine is not recorded but this is almost certainly a second oxidation zone specimen.

The tsumcorite has been XRD verified (Paul Carr; University of Wollongong, Australia; August 2024) but its chemical composition has not been determined.

goethite (?); quartz