Mineral description : Bertrandite

Possible bertrandite crystal from Sels-vitberget.
A minute yellow crystal in the center of the picture.

Mineral class Silicates : Beryl - tourmaline group
Chemical formula Be4Si2O7(OH)2
Crystal system Orthorombic
Habitus Tabular to prismatic crystals.
Cleavage Perfect.
Hardness 6-7
Density 2.6
Color Colorless to weakly yellow.
Streak  
Luster Vitreous.
Description  
Occurance Often an alteration product of Beryl.
Associates Beryl, phenakite, euclase.
Notes Bertrandite belongs to inosilicates.
Locations A rare mineral in Sweden.
  • Kolsva feldspar quarry, Västmanland.
  • Högsbo pegmatite, Göteborg. As alteration of beryl.
  • Stora vika lime stone quarry, Nynäshamn. As small crystals.
  • Ytterby pegmatite, Resarö. As small crystals on altered beryl.
  • Stimmersunda pegmatite, Askersund. As alteration of beryl.
  • Kårarvet, Falun. In a number of pegmatites in the area.
  • Reboda, SV Stripa, Västmanland. As alteration of beryl.
  • Råneå pegmatite, Norrbotten. As alteration of beryl.
  • Sels-vitberget, Bollstabruk. As alteration of beryl.

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Last changed : 1998-03-07