Mineral description : Erythrite

Erythrite from Bastnäs.
Erythrite from Morocco.

Mineral class Phosphates : Torbenite - Carnotite - Annabergite group.
Chemical formula Co3(AsO4)2*8H2O
Crystal system Monoclinic.
Habitus Crystal as flattened striated blades or radiating accicular aggregates. Most commonly as crusts or earthy masses.
Cleavage Perfect in one direction, fracture uneven.
Hardness 1.5-2.5
Density 3.07-3.18
Color Deep purple to pale pink.
Streak Pale pink.
Luster Adamantine to vitreous or pearly (on cleavages).
Occurance Forms in cobalt veins that's been altered by oxidising, either in air or by circulating fluids.
Associates Cobalt minerals as cobaltite, skutterudite
Notes Soluble in hydrochloric acid creating a pink solution.
Changes color to blue when heated.
Locations Less common mineral in Sweden.
  • Los mining district, Hälsingland.
  • Gladhammargruvan, Småland.
  • Lövåsen mine, Dalarna.
  • Bolidengruvan, Västerbotten.
  • Tunaberg mine, Södermanland.
  • Bastnäs, Riddarhyttan, Västmanland. As pinkish crusts on weathered stones.

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Last changed : 1998-06-14