Formula: CaCu6(AsO4)2(AsO3OH)(OH)6.3H2O
Hydrated arsenate containing hydroxyl, mixite group
Specific gravity: 3.49
Hardness: 2 to 3
Streak: Greenish white
Colour: Pale green, grass-green

Hydrothermal environments

Zálesíite is an oxidation product of chalcopyrite (Webmin). It is sometimes associated with pharmacolite (https://www.dakotamatrix.com).


At the type locality, the Zálesí uranium deposit, Zálesí, Javorník, Jeseník District, Olomouc Region, Czech Republic, Zálesííte forms minute, transparent, pale green acicular crystals up to 0.1 mm in length, which produce crystalline hair-like coatings up to 1 cm2 on quartz gangue, in veinlets and filling of small cavities up to 5 mm. It originated by weathering of chalcopyrite and cobalt arsenides in-situ in the supergene zone. Zálesíite was found in association with chalcopyrite, chrysocolla, clinoclase, conichalcite, erythrite, malachite, metanováčekite, metatorbernite, nováčekite, quartz, tyrolite, uranophane and zeunerite (Neues Jahrbuch für Mineralogie - Abhandlungen 175.105-124).

At the Hilarion Mine, Kamariza Mines, Agios Konstantinos, Lavrion Mining District, Lavreotiki, East Attica, Attica, Greece, agardite forms marginal zones up to 3 μm thick of larger zoned acicular crystals 10 to 15 μm long, with a core of zálesíite (AM 97.2064).

At the Taghouni Mine, Ouisselsate Caïdat, Amerzgane Cercle, Ouarzazate Province, Drâa-Tafilalet Region, Morocco, zálesíite can form with mixite (Minrec 38.5.402-405).

At the Aghbar Mine, Aghbar, Agdz Cercle, Zagora Province, Drâa-Tafilalet Region, Morocco, zálesíite occure as microscopic "hedgehog" sprays of blue-green fibrous crystals, sometimes with mixite (Minrec 38.5.402-405).

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