Formula: Co(AsO3OH).H2O (Co2+As5+)
Hydrated acid arsenate, koritnigite group
Specific gravity: 3.44 calculated
Hardness: 2 to 3
Streak: Pale pink
Colour: Pale to intense purple, pale rose red to intense purple-rose
Common impurities: Zn
At the Richelsdorf mining district, Hersfeld-Rotenburg, Kassel Region, Hesse, Germany, cobaltkoritnigite occurs as an alteration product of cobaltite (AM 67.414, Dana) associated with erythrite, cobaltite, calcite, baryte and quartz (HOM).
At the type locality, the Schwarzenberg mining district, Erzgebirgskreis, Saxony, Germany, cobaltkoritnigite occurs as a post-mining weathering product of glaucodot in cobalt ore. Associated minerals include erythrite–kottigite, cobaltite, spherocobaltite, pitticite, glaucodot, löllingite–safflorite, arsenopyrite and quartz (AM 67.414, HOM, Dana, Mindat).
At the Bou Azzer mining district, Drâa-Tafilalet Region, Morocco, cobaltkoritnigite is the most common weathering product of some cobalt ores such as skutterudite. At this locality the cobaltkoritnigite contains no zinc. It is widespread as efflorescences associated with erythrite and it found preferentially in cavity zones which are rich in arsenolite. At Tamdrost botryoids to 1 mm occur in cavities in erythrite-rich skutterudite (Minrec 38.5.368).
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