Mineral Information and Data:

Norbergite
Mg3SiO4F2 [CNMNC approved formula]

Named after the type locality: The Östanmoss Mine, Norberg, Västmanland, Sweden.

IMA status : Valid species (Pre-IMA 1926) Grandfathered
CLASSIFICATION 
Dana
(8th edition) :
52.03.02a.01  
  (52) Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O
  (52.03) with cations in [6] coordination only
  (52.03.02a) Humite group
  
Nickel-Strunz
(10th edition) :
09.AF.40
  (09) Silicates
  (09.A) Nesosilicates (Isolated tetrahedron) structures
  (09.AF) Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
  
Crystal system: Orthorhombic System
Point group (H-M): mmm (or 2/m 2/m 2/m) — dipyramidal
Unit cell: a = 10.27Å, b = 8.72Å, c = 4.7Å
Crystal Habit: Crystals varied habit, highly modified, rounded grains
  
Color: Tan, yellow, yellow-orange, orange-brown
Diaphaneity: Transparent to translucent
Luster: Vitreous to somewhat resinous
Hardness (Mohs): 6 to 6.5
Measured Density: 3.177 g/cm3
  
Geologic Setting: In contact metamorphic zones in limestones and dolostones into which plutonic rocks or pegmatites have introduced fluorine.
Mineral Association: Dolomite, calcite, tremolite, grossular, wollastonite, forsterite, monticellite,
cuspidine, °uoborite, ludwigite, fluorite, phlogopite
  
Luminescent Properties: May fluoresce canary-yellow under
SW UV.

 

Norbergite
Yellow, crude crystal grains to 3 mm in calcite matrix
Origin: Cardiff Uranium mine, Ontario, Canada
Sample size: 5 x 3 x 2 cm
Photo: Tom Loomis

 

Norbergite
(zoom-in of above)

 

Norbergite
Norbergite on calcite
Origin: Oak Saung Tang, Mogok, Mandalay Div., Myanma, Burma
Sample size: 5.6 x 4.3 x 4 cm
Photo: John Veevaert, Trinity Mineral Co

 

Norbergite
(zoom-in of above)

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