Pseudomalachite

This specimen is Pseudomalachite from the West Bogan Mine, Tottenham District, New South Wales, Australia, measuring 69 x 25 x 20 mm and weighing 75 g. It is recorded with the David Vince Collection and the Jim Sharpe Collection. Pseudomalachite is a copper phosphate, usually occurring as botryoidal or fibrous crusts in shades of green that can superficially resemble Malachite, the origin of its name, despite the two being chemically distinct species. It forms in the oxidised zones of copper deposits where phosphate is also present in the system, a combination not found at every copper locality. The Tottenham district in central New South Wales is a lesser-known Australian source for the species, reflecting a regional phosphate-bearing copper occurrence distinct from the state's larger and better-known sulphide fields. At 69 x 25 x 20 mm and 75 g, the specimen is an elongated cabinet piece well suited to showing its crust development along its length. Pseudomalachite is moderately stable under normal display conditions. The specimen carries a double provenance, recorded from both the David Vince Collection and the Jim Sharpe Collection.