Pseudomalachite is a phosphate of copper with hydroxyl, named from the Greek for "false" and "malachite", because of its similarity in appearance to the carbonate mineral malachite, Cu2(CO3)(OH)2. Both are green coloured secondary minerals found in oxidised zones of copper deposits, often associated with each other. Pseudomalachite is polymorphous with reichenbachite and ludjibaite. It was discovered in 1813. Prior to 1950 it was thought that dihydrite, lunnite, ehlite, tagilite and prasin were separate mineral species, but Berry analysed specimens labelled with these names from several museums, and found that they were in fact pseudomalachite. The old names are no longer recognised by the IMA.Berry L G (1950). American Mineralogist 35: 365 to 385
Type locality The type locality is the Virneberg Mine, Rheinbreitbach, Westerwald, Rhineland-Palatinate, Germany. This is an area of ancient copper mining dating back to Roman times, and worked intermittently up until 1872. The type material is held at the Mining Academy, Freiberg, Germany.
Structure The copper ions are co-ordinated by six oxygen ions to form distorted octahedra.Ghose, Subrata (1963) The Crystal Structure of Pseudomalachite. Acta Crystallographica 16:124–128 These octahedra are linked by sharing edges to form two distinct types of infinite chains, parallel to b. The chains are linked alternately, again by sharing octahedral edges, to form sheets parallel to the bc plane. Distorted phosphate tetrahedra link the sheets, and there is some doubt about the exact position of the hydrogen ions in the structure.Shoemaker, G L, Anderson, J B and Kostiner, E (1977). American Mineralogist 62: 1042 to 1048
Environment It is a secondary mineral found in the oxidised zones of copper ore deposits. Associated with libethenite at several localities in New South Wales, Australia,The Australian Journal of Mineralogy 3:50, 10:55, 10:79, 11:97 and 11:117 to 118 and at the Chino Mine, New Mexico, US.Rocks & Minerals (2009) 84:6 page 498 Other associated minerals are apatite, azurite, chalcedony, chrysocolla, cornetite, cuprite, malachite, pyromorphite, tenorite, and iron oxyhydroxides.
Distribution
Pseudomalachite has been reported from Argentina, Australia, Austria, Belgium, Brazil, Canada, Chile, Czech Republic, Democratic Republic of Congo, France, Germany, Ireland, Israel, Italy, Japan, Kazakhstan, Madagascar, Mexico, Namibia, Norway, Poland, Portugal, Republic of Congo, Romania, Russia, Slovakia, South Africa, Spain, UK, US and Zambia.
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