Mineral description : Rhodonite

Rhodonite from Harstigen.
Rhodonite from Garpenberg.

Mineral class Silicates : Nesosilicates : Braunite group
Chemical formula CaMn4(Si5O15)
Crystal system Triclinic
Habitus Crystals tabular with rounded edges. Mostly as grainy or compact masses.
Cleavage Perfect prismatic in 90 degrees, conchoidal to uneven fracture.
Hardness 5.5-6.5
Density 3.57-3.76
Color Pink to rose red and brownish red. Often with a black surface of manganese oxide.
Streak White.
Luster Vitreous, pearly on cleavage surfaces.
Occurance In metamorphic rocks rich in manganese.
As a scarn mineral of manganese ores.
Notes Insoluble in hydrochloric acid.
Fuses easily, leaving a red to brownish red glassy substance.
Locations A common mineral in the Värmlandic manganese mines.
  • Långban, Värmland. As stalky grainy masses with schefferite, tephroite and richterite.
  • Harstigen, Värmland. As crystal up to 2 cm in calcite filled rooms.
  • Sjögruvan, Grythyttan. As fist sized compact light red rhodonite.
  • Also in : The Nordmark mines. Gladtjärnsgruvan, Lindesberg. Norberg mining field. Dannemora mine, Uppland.

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Last changed : 1998-03-07