Mineral description : Staurolite

Staurolite from Fauske, Norway.
Twin crystal between almandine in schist.
Staurolite from Fauske, Norway.
Twin crystal with almandine in schist.
Staurolite from Fauske, Norway.
Staurolite and almandine in a compact mass.

Mineral class Silicates : Nesosilicates : topaz - staurolite group
Chemical formula FeAl4(O/OH/SiO4)2
Crystal system Orthorombic
Habitus Often as short prismatic crystals with twins. Also as grains in some rocks.
Cleavage Distinct, fracture uneven to subconchoidal.
Hardness 7-7.5
Density 3.65-3.83
Color Dark brown , yellowish brown to black. Often with transformed surfaces.
Streak Colorless to grayish.
Luster Vitreous to resinous.
Description Forms at regional metamorphose at high pressures and temperatures.
Occurance In gneiss, mica schist and quartzites.
Associates Kyanite, muscovite, garnet, quartz.
Notes Varieties with traces of manganese is fusable.
Locations A rather common accessoric mineral
  • Bergslagen. As accessorial mineral in schist.
  • Skellefteå mining field. As accessorial mineral in schist.
  • V. Silvberg field, Ludvika. As crystals in schist.
  • Kalvbäcksgruvan, Falu area. As crystals in schist.
  • Hans-Urbanson field, Riddarhyttan, Västmanland.
  • Fauske, Norway. As fine black crystals in muscovite schist with almandine.

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Last changed : 1998-03-28