Mineral description : Cassiterite

Cassiterite from Varuträsk.
In cleavelandite and quartz.
Cassiterite from Varuträsk.
3 cm piece with biotite.

Mineral class Oxides : Rutil-cassiterite group.
Chemical formula SnO2
Crystal system Tetragonal.
Habitus Often as short prismatic crystals. Also as small grains or banded fibric masses.
Cleavage Poor, fracture subconchoidal to uneven.
Hardness 6-7
Density 6.8-7.1
Color Black, but also yellowish and colorless. Translucent to opaque.
Streak White to weakly brownish.
Luster Adamantine, greasy on fractures.
Occurance In pegmatites, high temperature hydrothermal veins and some metamorphic rocks.
Notes Cassiterite is insoluble in acids and infusible.
Locations A rare mineral in Sweden.
  • Varuträsk, Västerbotten. Common as poorly developed crystals, streak color reddish brown.
  • Utö, Stockholm. As small grains.
  • Finnbo, Falun.
  • Between lake Storflaten and lake Van, Leksand.

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Last changed : 1998-06-17