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Ekatite Mineral Data

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General Ekatite Information

Help on Chemical  Formula: Chemical Formula: (Fe+++,Fe++,Zn)12(OH)6[AsO3]6[AsO3,HOSiO3]2
Help on Composition: Composition: Molecular Weight = 1,761.38 gm
   Zinc       2.97 %  Zn    3.70 % ZnO
   Iron      35.51 %  Fe   21.21 % FeO / 27.20 % Fe2O3
   Silicon    0.96 %  Si    2.05 % SiO2
   Arsenic   32.33 %  As   42.68 % As2O3
   Hydrogen   0.35 %  H     3.12 % H2O
   Oxygen    27.89 %  O
            ______        ______ 
            100.00 %       99.95 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Fe3+6Fe2+5.2Zn0.8(OH)6.1(AsO3)7.6(SiO3)0.6
Help on Environment: Environment: Oxidation product occurring on a matrix of chalcocite and etched quartz.
Help on IMA Status: IMA Status: Approved IMA 1998 (Dana # Added)
Help on Locality: Locality: Tsumeb mine, Namibia. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Dieter Ekat (1935-1996), Namibian mining engineer.
Help on Synonym: Synonym: IMA1998-024

Ekatite Image

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Comments: Divergent spray of dark brown acicular ekatite crystals.
Location: Tsumeb mine, Namibia.. Scale: 15 mm Tall.
© William Pinch

Ekatite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:0.39544
Help on Cell Dimensions: Cell Dimensions: a = 12.773, c = 5.051, Z = 1; V = 713.66 Den(Calc)= 4.10
Help on Crystal System: Crystal System: Hexagonal - Dihexagonal Pyramidal H-M Symbol (6mm) Space Group: P 63mc
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.22(1)(211,220), 2.42(0.7)(401,410), 6.37(0.5)(110),1.788(0.4), 2.531(0.4), 2.766(0.3)(400), 11.11(0.3)(100), 1.507(0.3)(701,431), 1.672(0.3)(521),

Physical Properties of Ekatite

Help on Cleavage: Cleavage: None
Help on Color: Color: Brownish black.
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Aggregates - Made of numerous individual crystals or clusters.
Help on Habit: Habit: Striated - Parallel lines on crystal surface or cleavage face.
Help on Hardness: Hardness: 3 - Calcite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: brown

Optical Properties of Ekatite

Help on Gladstone-Dale: Gladstone-Dale: CI calc= -0.024 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2524,KC= 0.2466
Ncalc = 2.01
Help on Optical Data: Optical Data: Uniaxial (+), w=1.99, e=2.08, bire=0.0900.

Calculated Properties of Ekatite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.85 gm/cc
note: Specific Gravity of Ekatite =4.10 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0093271825
Boson Index = 0.9906728175
Help on Photoelectric: Photoelectric: PEEkatite = 34.84 barns/electron
U=PEEkatite x rElectron Density= 134.00 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Ekatite is Not Radioactive

Ekatite Classification

Help on  Dana Class: Dana Class: (43)Compound Phosphates, etc.
  (43.04)(Anhydrous Compound Anions With Hydroxyl or Halogen)
  (43.04.10)Kraisslite Group Kraisslite (Mn,Mg)24Zn3Fe(AsO3)2(AsO4)3(SiO4)6(OH)18 P 6322 6 2 2 Ekatite! (Fe,Fe,Zn)12(OH)6[AsO3]6[AsO3,HOSiO3]2 P 63mc 6mm
Help on  Strunz Class: Strunz Class: 04.JB.75 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.J - Arsenites, Antimonites, Bismuthites, Sulfites,
  04.JB -Arsenites, antimonites, bismuthites; with additional anions, without H2O
04.JB.75 Ekatite! (Fe,Fe,Zn)12(OH)6[AsO3]6[AsO3,HOSiO3]2 P 63mc 6mm

Other Ekatite Information

Help on References: References: NAME( AmMin, Vol 87, p 355) PHYS. PROP.(AmMin, Vol 87, p 355) OPTIC PROP.(AmMin, Vol 87, p 355)
Help on See Also: See Also: Links to other databases for Ekatite :
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: 04.JB.75





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