Mineralogy Database

Turtmannite Mineral Data

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General Turtmannite Information

Help on Chemical  Formula: Chemical Formula: (Mn,Mg)25.5[(V,As)O4]3(SiO4)3[AsO3]xO5-5x(OH)20+x
Help on Composition: Composition: Molecular Weight = 2,396.92 gm
   Magnesium   2.54 %  Mg    4.20 % MgO
   Manganese  52.72 %  Mn   68.07 % MnO
   Vanadium    4.78 %  V     8.54 % V2O5
   Silicon     3.52 %  Si    7.52 % SiO2
   Arsenic     3.28 %  As    1.24 % As2O3 /  3.60 % As2O5
   Hydrogen    0.84 %  H     7.53 % H2O
   Oxygen     32.33 %  O
             ______        ______ 
             100.00 %      100.69 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Mn2+23Mg2.5(VO4)2.25(AsO4)0.75(SiO4)3(AsO3)0.3O3.5(OH)20.03
Help on Environment: Environment: Manganoan paleokarst lenses in Triassic marbles metamorphosed to upper greenshist facies. Similar to mcgovernite; structure
Help on IMA Status: IMA Status: Approved IMA 2000 (Dana # Added)
Help on Locality: Locality: Barrhorn Unit (Central Alps) in the Triassic marbles near Turtmanntal, Valais, Switzerland. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after the locality.

Turtmannite Image

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Comments: Orange-brownish grains of turtmannite in matrix.
Location: Pipji Glacier, Turtmanntal (Turtmann Valley), Wallis (Valais), Switzerland. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Turtmannite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:2.47003
Help on Cell Dimensions: Cell Dimensions: a = 8.259, c = 20.4, Z = 1; V = 1,205.08 Den(Calc)= 3.30
Help on Crystal System: Crystal System: Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3c
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.86(1), 1.559(0.9), 3.26(0.8),4.13(0.7), 2.38(0.6), 3.46(0.6), 2.35(0.5),

Physical Properties of Turtmannite

Help on Cleavage: Cleavage: {0001} Perfect
Help on Color: Color: Bright yellow, Orange.
Help on Density: Density: 3.6 - 4, Average = 3.8
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Anhedral Grains - Granular minerals without the expression of crystal shapes
Help on Habit: Habit: Micaceous - Platy texture with "flexible" plates.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: colorless

Optical Properties of Turtmannite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.065 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= -0.077 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2385,KPDmeas= 0.2071,KC= 0.2215
Ncalc = 1.73 - 1.89
Help on Optical Data: Optical Data: Uniaxial (-), e=1.787.

Calculated Properties of Turtmannite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.62 gm/cc
note: Specific Gravity of Turtmannite =3.80 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0044526019
Boson Index = 0.9955473981
Help on Photoelectric: Photoelectric: PETurtmannite = 17.04 barns/electron
U=PETurtmannite x rElectron Density= 61.62 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Turtmannite is Not Radioactive

Turtmannite Classification

Help on  Dana Class: Dana Class: (43)Compound Phosphates, etc.
  (43.04)(Anhydrous Compound Anions With Hydroxyl or Halogen)
  (43.04.09)Mcgovernite Group Mcgovernite Mn9Mg4Zn2As2Si2O17(OH)14 R 3c 3 2/m Turtmannite! (Mn,Mg)25.5[(V,As)O4]3(SiO4)3[AsO3]xO5-5x(OH)20x R 3c 3 2/m
Help on  Strunz Class: Strunz Class: 08.BE.45 08 - PHOSPHATES, ARSENATES, VANADATES
  08.B - Phosphates, etc. with Additional Anions, without H2O
  08.BE -With only medium-sized cations, (OH, etc.):RO4 > 2:1
08.BE.45 Dixenite CuMn14Fe(AsO3)5(SiO4)2(AsO4)(OH)6 R 3 3
08.BE.45 Hematolite (Mn,Mg,Al)15(AsO3)(AsO4)2(OH)23 R 3 3
08.BE.45 Kraisslite (Mn,Mg)24Zn3Fe(AsO3)2(AsO4)3(SiO4)6(OH)18 P 6322 6 2 2
08.BE.45 Mcgovernite Mn9Mg4Zn2As2Si2O17(OH)14 R 3c 3 2/m
08.BE.45 Turtmannite! (Mn,Mg)25.5[(V,As)O4]3(SiO4)3[AsO3]xO5-5x(OH)20x R 3c 3 2/m
08.BE.45 Arakiite! (Zn,Mn)(Mn,Mg)12(Fe,Al)2(AsO3)(AsO4)2(OH)23 Cc m

Other Turtmannite Information

Help on References: References: NAME( AmMin, Vol 86, p 1494-1505) PHYS. PROP.(AmMin, Vol 86, p 1494-1505) OPTIC PROP.(AmMin, Vol 86, p 1494-1505)
Help on See Also: See Also: Links to other databases for Turtmannite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Dana No: Strunz No: 08.BE.45





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