Mineral Information and Data:

Bararite
(NH4)2SiF6 [CNMNC approved formula]

Named after the locality: Bararee colliery, Barari Bengal, India.

IMA status : Valid species (Pre-IMA 1951) Grandfathered
CLASSIFICATION 
Dana
(8th edition) :
11.05.02.02  
  (11) Halide Complexes; Alumino-fluorides
  (11.05) where (A)m B (X)6
  (11.05.02) Malladrite Group
  
Nickel-Strunz
(10th edition) :
03.CH.10
  (03) Halides
  (03.C) Complex Halides
  (03.CH) Silicofluorides
  
Crystal system: Trigonal System
Point group (H-M): 3m (or 3 2/m) — hexagonal-scalenohedral
Unit cell: a = 5.77Å, c = 4.78Å
Crystal Habit: Crystals tabular; crusts, mammillary, arborescent
  
Color: White; colorless in thin section
Diaphaneity: Transparent
Luster: Vitreous
Hardness (Mohs): 2.5
Measured Density: 2.152 g/cm3
Cleavage: 1; {0001}perfect
  
Polymorphism and Series: Dimorphous with cryptohalite, the higher-temperature form.
Geologic Setting: Above a burning coal seam (Barari, India); a sublimation product at fumaroles
(Vesuvius, Italy); a sublimation product in burning anthracite piles (Pennsylvania, USA).
Mineral Association: Cryptohalite, sal ammoniac, sulfur
  
Synonyms/varieties: Baryte, hokutolite (Pb-rich var.)
Other Properties: H2O Soluble.
Comments: With a saline taste.

 

Bararite
White crystalline bararite intermixed
with cryptohalite colored yellow by selenium.
Origin: Shamokin, Northumberland County, Pennsylvania, USA.
Photo: Jeff Weissman
Photo : © Jeff Weissman / Photographic Guide to Mineral Species

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