Mineral description : Cookeite

Rubellite transformed into cookeite from Varuträsk, Västerbotten.

Chemical formula LiAl3(OH)6(Si2O6)
Hardness 2.5
Density 2.6
Color Light yellow-green to light pink
Luster ?
Description Fine grained and compact masses.
Notes Formed by transformation of rubellite. Also as fillings in cracks.
Locations A rare mineral in Sweden. Found at the following locations :
  • Varuträsk pegmatite, Västerbotten.
  • Helgeland, Norway.
  • In the Viitaniemi pegmatite, Finland.
  • In the Haapaluoma pegmatite, Finland.

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Last changed : 1998-03-07