Mineral Information and Data:

Anandite
BaFe2+3(Si3Fe3+)O10S(OH) [CNMNC approved formula]

Named for Ananda Kentush Coomaraswamy (1877-1947), first director of the Mineral Survey of Ceylon (Sri Lanka).

IMA status : Approved Species 1967 (IMA1966-005)
CLASSIFICATION 
Dana
(8th edition) :
71.02.02c.04  
  (71) Phyllosilicate Sheets of Six-Membered Rings
  (71.02) with 2:1 Layers
  (71.02.02c) Mica Group (Margarite subgroup)
  
Nickel-Strunz
(10th edition) :
09.EC.35
  (09) Silicates
  (09.E) Phyllosilicates
  (09.EC) Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
  
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Unit cell: a = 5.412(5) Å, b = 9.434(5) Å, c = 19.953(10) Å; β = 95°
Crystal Habit: Massive; cleavage flakes with hexagonal outlines
  
Color: Black
Diaphaneity: Nearly opaque
Luster: Vitreous
Hardness (Mohs): 3 - 4
Measured Density: 3.94 g/cm3
Cleavage: 1; {001} perfect
Streak: Gray white
  
Polymorphism and Series: 2O, 2M1, 1M polytypes.
Geologic Setting: As monomineralic veinlets and lenses in a banded magnetite deposit capped by banded magnetite-barite rock. The ore zone and associated interbedded calc-schists and gneisses are of metasedimentary origin, of approximately granulite facies grade.
Mineral Association: Magnetite, chalcopyrite, pyrite, pyrrhotite, barite
  

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