Mineral description : Pyrolusite

Pyrolusite from Harstigen.

Mineral class Oxides : Pyrolusite - Manganite group
Chemical formula MnO2
Crystal system Tetragonal
Habitus Dendritic or massive fibric aggregates. Crystals are prismatic but very rare.
Cleavage Perfect, uneven fracture.
Hardness 2 (-6.5)
Density 5.2
Color Matte black to dark gray.
Streak Black to bluish black.
Luster Metallic to earthy.
Occurance As dendritic forms in Dolomite cracks.
As massive fibric aggregates.
Pyrolusite is a secondary mineral in manganese occurances.
Also forms asnodules in the oceans and as precipitate in lakes.
Notes Soluble in hydrochloric acid.
    Pyrolusite is a less common manganese ore in Sweden.
  • Harstigen, Persberg. As dendrites in dolomite cracks.
  • Bölet manganese mine, Undenäs, Västergötland.
  • Spexaryd manganese mine, south Jönköping.

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Last changed : 1998-03-07