Mineral description : Albite

Albite in the form of cleavelandite from Varuträsk.
Albite in the form of albitite from Varuträsk.
Albite crystals with asphaltite from Granmuren.

Mineral class Silicates : Tektosilicates : Feldspar group.
Chemical formula (Na,Ca)(AlSi3O8) (100-90% Na, 0-10% Ca)
Crystal system Triclinic.
Habitus Tabular to prismatic, commonly with polysyntetic twinning. Often occuring in lamellar aggregates (cleavelandite) or as grainy aggregates (albitite).
Cleavage Perfect in one direction and good in another with 90 degrees angle.
Often with fine striation on cleavages.
Hardness 6-6.5
Density 2.62
Color White to colorless.
Streak White
Luster Vitreous to pearly. Transparent to translucent.
Description  
Occurance As a major part of many rocks, especially igneous rocks as granites, syenites and pegmatites.
Associates  
Notes Twinning often produces many layers on top of each other, each only a fraction of a mm to several mm thick. Theese layers can be seen as striations not only on the surface of the crystal, but also on cleavages. This is a characteristic sign of the plagioclase feldspar series.
Locations A very common mineral.
  • In the quartz - feldspar quarries of Bohuslän.
  • Malmberget, Lappland. As crystal druses of up to 10 cm size.
  • Varuträsk, Västerbotten. Commonly as aggregates of cleavelandite
  • Väne Ryr quartz quarry, Vänersborg, Västergötland. As cleavelandite.
  • Riddarho quartz quarry, Värmland. As cleavelandite.

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Last changed : 1998-08-29