Zálesíite

zalesiite

agardite

pharmacolite

chalcopyrite

Images

Formula: CaCu6(AsO4)2(AsO3OH)(OH)6.3H2O
Hydrated arsenate containing hydroxyl, mixite group
Crystal System: Hexagonal
Specific gravity: 3.49 measured, 3.50 calculated
Hardness: 2 to 3
Streak: Greenish white
Colour: Pale green, grass-green
Environments

Hydrothermal environments

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

Localities

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).

In the Black Forest, Baden-Württemberg, Germany, mixite-group minerals mostly consist of zálesíite with elevated bismuth or rare earth element contents or both. It originates in baryte veins with copper-bismuth mineralisation in sandstone overlying granite. The sandstones were covered by limestone (CM 49.5.1305–1333).

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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