Bieberite

Bieberite
A 4.4 by 2.7 cm mass of mainly grey bismuth covered by a thin film of pinkish bieberite from an old classic Locality, Schlema, Schlema-Hartenstein District, Erzgebirge, Saxony, Germany
General
CategorySulfate mineral
FormulaCoSO4·7H2O
IMA symbolBie
Strunz classification7.CB.35
Dana classification29.6.10.4
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
Space groupP2/m
Identification
ColorRose-red, red-pink, flesh-red
Crystal habitCrusts, stalactites
Cleavage{001} perfect, {110} fair
Mohs scale hardness2
LusterVitreous
DiaphaneitySubtransparent
Specific gravity1.96
Density1.96 (measured), 1.83 (calculated)
Optical propertiesBiaxial (+), colorless to pale rose color (transmitted light)
2V angle88° (measured), 88° (calculated)
SolubilitySoluble in water
References

Bieberite (CoSO4 · 7H2O) is a pinkish red colored sulfate mineral high in cobalt content. The name is derived from the type locality at the copper deposit in Bieber, Hesse, Germany. It has been described and reported as far back as the 1700s. Bieberite primarily occurs as a secondary mineral, forming in cobalt-bearing arsenide and sulfide deposits through oxidation.

Natural bieberite crystals may have a small amount of cobalt lattice sites instead occupied by magnesium and copper (Palache et al., 1960).