Norbergite

Norbergite is named after its discovery locality at Norberg, Sweden.

Norbergite forms translucent to opaque, tan, yellow, yellow-orange, orange-brown, pink with purplish tint, white granular masses. Transparent crystals are very rare.

Norbergite is often cut into cabochons.
General Information
Chemical Formula
Mg
 
3
(SiO
 
4
)(F,OH)
 
2
Anthony et al, Handbook of Mineralogy (2001)
Photos of natural/un-cut material from mindat.org
Physical Properties of Norbergite
Mohs Hardness6 to 6.5
Anthony et al, Handbook of Mineralogy (2001)
Specific Gravity3.177
Anthony et al, Handbook of Mineralogy (2001)
TenacityBrittle
Anthony et al, Handbook of Mineralogy (2001)
FractureUneven,Sub-Conchoidal
Anthony et al, Handbook of Mineralogy (2001)
Optical Properties of Norbergite
Refractive Index1.563 to 1.593
Anthony et al, Handbook of Mineralogy (2001)
Optical CharacterBiaxial/+
Anthony et al, Handbook of Mineralogy (2001)
PleochroismPale yellow - very pale yellow - colorless
Anthony et al, Handbook of Mineralogy (2001)
Colour
Colour (General)Tan, yellow, yellow-orange, orange-brown, pink with purplish tint, white; in thin section, pale yellow to colorless
Anthony et al, Handbook of Mineralogy (2001)
TransparencyTransparent,Translucent
Anthony et al, Handbook of Mineralogy (2001)
LustreVitreous,Resinous
Anthony et al, Handbook of Mineralogy (2001)
Fluorescence & other light emissions
Fluorescence (Short Wave UV)May fluoresce canary-yellow
Anthony et al, Handbook of Mineralogy (2001)
Crystallography of Norbergite
Crystal SystemOrthorhombic
Anthony et al, Handbook of Mineralogy (2001)
HabitCrystals rare, to 2.5 cm, thick tabular, typically rounded and highly modified; granular.
Anthony et al, Handbook of Mineralogy (2001)
Geological Environment
Where found:In contact metamorphic zones in limestones and dolostones into which plutonic rocks or pegmatites have introduced fluorine.
Anthony et al, Handbook of Mineralogy (2001)
Further Information
Mineral information:Norbergite information at mindat.org
Significant Gem Localities
USA
 
  • New Jersey
    • Sussex Co.
      • Franklin Mining District
        • Franklin
          • Franklin Marble
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