Wroewolfeite

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Formula: Cu₄(SO₄)(OH)₆.2H₂O
Hydrated sulphate containing hydroxyl, paramorph of langite
Crystal System: Monoclinic
Specific gravity: 3.27
Hardness: 2½
Streak: Blue-green
Colour: Intense blue-green, bluish
Environments

Hydrothermal environments

Wroewolfeite is an uncommon late-stage supergene copper mineral typically formed as microcrystals in the oxidised zone of copper-bearing hydrothermal ore deposits and in post-mining dump environments (MW, HOM). It generally forms at low temperatures (Mindat). Associated minerals include langite, posnjakite, serpierite, brochantite, linarite, malachite, chalcocite and covellite (HOM).

Localities

At St Görans Mine, Bastnäs Mines, Riddarhyttan, Skinnskatteberg, Västmanland, Sweden, crystals of wroewolfeite to 2 mm have been found in the iron ore on massive cuprite, and also in druses with lanthanite crystals in the actinolite skarn (Minrec 35.3.198).

At Red Gill Mine, Roughton Gill, Caldbeck, Allerdale, Cumbria, England, UK, crystals of wroewolfeite to 0.5 mm long have been found in a cavity in a chalcopyrite matrix (JRS 11.43).

At Silver Gill, Roughton Gill, Caldbeck, Allerdale, Cumbria, England, UK, wroewolfeite has been found as crystals up to 0.3 mm long, associated with hemimorphite and langite; Some of the crystals are partially altered to brochantite (JRS 8(2).94)

At the Eaglebrook mine, Ceulanymaesmawr, Ceredigion, Wales, UK, Clear, sharp, wroewolfeite occurs as blades exceeding 1 mm in length, associated with linarite and brochantite, both of which pre-date the wroewolfeite (MW).

At the Frongoch mine, Devil's Bridge, Ceredigion, Wales, UK, wroewolfeite forms part of the mixed basic sulphate-covellite replacement of galena and cerussite, and occurs rarely with hemimorphite. Microcrystals of wroewolfeite associated with minute cerussite crystals have been collected from underground workings (MW).

At the Esgairhir mine, Tal-y-bont, Ceredigion, Wales, UK, wroewolfeite is a very rare component of the supergene assemblage. Crystals up to 0.8 mm have been found, typically encrusting or associated with altered chalcopyrite. Associated minerals include all the other basic sulphate minerals and also, on rare occasions, cerussite (MW).

At the Glasdir mine, Dolgellau Gold-belt, Gwynedd, Wales, UK, wroewolfeite occurs as aggregates of blue microcrystals associated with malachite on shale (MW).

At the Drws-y-Coed mine, Nantlle, Gwynedd, Wales, UK, wroewolfeite forms blades to 1 mm in length, associated with amorphous crusts on calcite (MW).

The type locality is the Loudville Lead mines, Easthampton, Hampshire county, Massachusetts, USA. Wroewolfeite occurs in this old lead mine in the oxidation zone, as minute crystals to 1.0 mm, associated with chalcocite, covellite and langite. It alters to brochantite and malachite (AM 61.179, Dana).

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