Formula: Pb(Ni,Fe3+)2(AsO4)2(H2O,OH)2
Arsenate, tsumcorite group, forms a solid-solution series with nickellotharmeyerite
Crystal System: Monoclinic
Specific gravity: 5.02 calculated
Hardness: 4
Streak: Yellow
Colour: Yellow, brownish yellow, light brown or brown
Common impurities: Ca

Hydrothermal environments


At the type locality, Km 3 open pit, Km 3 mines, Km 3, Lavrion Mining District, Lavreotiki, East Attica, Attica, Greece, nickeltsumcorite was found in the oxidation zone of a hydrothermal orebody containing gersdorffite and galena. It is associated with annabergite, nickellotharmeyerite, nickelaustinite, gaspéite, calcite, dolomite, aragonite, quartz, goethite, cerussite, arseniosiderite, mimetite, oxyplumboroméite and manganese oxides and hydroxides. Nickeltsumcorite occurs as open-work aggregates and interrupted crusts up to 3 mm × 5 mm in area and up to 0.2 mm thick. They typically consist of coarse radial spherulites or dense concentric nodules up to 0.15 mm in diameter. Bunches or hemispherical clusters of crude individuals and separate imperfect, elongated crystals (up to 0.02 mm long) are also observed (MM 80.337-346).

Nickeltsumcorite from the Km 3 Open Pit - Image

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