Schulenbergite

schulenbergite

linarite

spangolite

namuwite

Images
Formula: (Cu,Zn)7(SO4)2(OH)10.3H2O
Hydrated sulphate containing hydroxyl
Specific gravity: 3.28
Hardness: 2
Streak: Pale blue-green
Colour: Light blue to blue-green
Environments

Hydrothermal environments

Schulenbergite is a rare secondary mineral formed in the oxidised zone of copper-zinc bearing hydrothermal mineral deposits, commonly post-mine in copper-zinc slags. Associated minerals include namuwite, brochantite, posnjakite, ktenasite, serpierite, linarite, malachite, cerussite, hemimorphite, smithsonite, gypsum, chalcopyrite, sphalerite and quartz (HOM).

Localities

At the Kintore open cut, New South Wales, Australia, schulenbergite has been found with serpierite and brochantite as crystals to 0.1 mm across. The matrix is usually etched quartz containing copper altering to cuprite (AJM 3.1.43).

At the type locality, the Glücksrad mine, Oberschulenberg, Clausthal-Zellerfeld, Goslar, Lower Saxony, Germany, schulenbergite is associated with spangolite and namuwite (AM 70.438).

At Penberthy Croft Mine, St Hilary, Mounts’s Bay District; Betterton, Cornwall, England, UK, schulenbergite occurs as platy crystals up to about 1 mm in size on the surface of a quartz-rich slate without any other mineral associates. Vein quartz is present as a thin, irregular vein 1–2 mm thick on the surface of the slate matrix about 3 mm away from the schulenbergite crystal groups. Schulenbergite is an uncommon secondary mineral formed by supergene oxidation processes in copper and zinc bearing hydrothermal polymetallic deposits, and as a post-mining alteration product of primary chalcopyrite and sphalerite. These sulphides may all have been consumed here during the formation of the schulenbergite (JRS 19.34-35).

At Silver Gill, Caldbeck Fells, Cumbria, England, UK, schulenbergite occurs as aggregates to 0.3 mm across, associated wih ramsbeckite, posnjakite and linarite (JRS 8(2).85-97).

At the Smallcleugh Mine, Nenthead, Alston Moor, Eden, Cumbria, England, UK, post-mining groundwater has oxidised primary minerals, leading to the formation of gypsum, which in places encrusts the mine walls accompanied by various iron oxides, epsomite and rare serpierite. Locally these are associated with the secondary copper zinc basic sulphates schulenbergite and namuwite.
At Smallcleugh schulenbergite is sparsely present as pearly, blue-green trigonal crystals which exhibit either sharp or rounded corners, together with a perfect basal cleavage. The serpierite is present as turquoise to copper-blue mm long bundles comprising wispy or stellate acicular groups.
Textural evidence tentatively suggests that the schulenbergite and namuwite at the Smallcleugh Mine formed later than the serpierite and as the former have lower copper:zinc ratios than serpierite it appears that within the supergene assemblage copper became progressively depleted (JRS 3.23-24).

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