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Ekatite Mineral Data
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General Ekatite Information
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 Chemical Formula: |
(Fe+++,Fe++,Zn)12(OH)6[AsO3]6[AsO3,HOSiO3]2 |
| Composition: |
Molecular Weight = 1,761.38 gm |
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Zinc 2.97 % Zn 3.70 % ZnO |
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Iron 35.51 % Fe 21.21 % FeO / 27.20 % Fe2O3 |
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Silicon 0.96 % Si 2.05 % SiO2 |
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Arsenic 32.33 % As 42.68 % As2O3 |
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Hydrogen 0.35 % H 3.12 % H2O |
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Oxygen 27.89 % O |
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______ ______ |
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100.00 % 99.95 % = TOTAL OXIDE |
| Empirical Formula: |
Fe3+6Fe2+5.2Zn0.8(OH)6.1(AsO3)7.6(SiO3)0.6 |
| Environment: |
Oxidation product occurring on a matrix of chalcocite and etched quartz. |
| IMA Status: |
Approved IMA 1998 (Dana # Added) |
| Locality: |
Tsumeb mine, Namibia. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Dieter Ekat (1935-1996), Namibian mining engineer. |
| Synonym: |
IMA1998-024 |
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Ekatite Image |
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Images:
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Ekatite
Comments: Divergent spray of dark brown acicular ekatite crystals.
Location: Tsumeb mine, Namibia..
Scale: 15 mm Tall.
© William Pinch |
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Ekatite Crystallography
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| Axial Ratios: |
a:c = 1:0.39544 |
| Cell Dimensions: |
a = 12.773, c = 5.051, Z = 1; V = 713.66 Den(Calc)= 4.10 |
| Crystal System: |
Hexagonal - Dihexagonal Pyramidal H-M Symbol (6mm) Space Group: P 63mc |
| 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), |
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Physical Properties of Ekatite
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| Cleavage: |
None |
| Color: |
Brownish black. |
| Diaphaneity: |
Transparent |
| Fracture: |
Brittle - Generally displayed by glasses and most non-metallic minerals. |
| Habit: |
Acicular - Occurs as needle-like crystals. |
| Habit: |
Aggregates - Made of numerous individual crystals or clusters. |
| Habit: |
Striated - Parallel lines on crystal surface or cleavage face. |
| Hardness: |
3 - Calcite |
| Luster: |
Vitreous (Glassy) |
| Streak: |
brown |
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Optical Properties of Ekatite
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| Gladstone-Dale: |
CI calc= -0.024 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2524,KC= 0.2466
Ncalc = 2.01 |
| Optical Data: |
Uniaxial (+), w=1.99, e=2.08, bire=0.0900. |
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Calculated Properties of Ekatite
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| Electron Density: |
Bulk Density (Electron Density)=3.85 gm/cc
note: Specific Gravity of Ekatite =4.10 gm/cc.
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| Fermion Index: |
Fermion Index = 0.0093271825
Boson Index = 0.9906728175 |
| Photoelectric: |
PEEkatite = 34.84 barns/electron
U=PEEkatite x rElectron Density= 134.00 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Ekatite is Not Radioactive |
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Ekatite Classification
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| Dana Class: |
43.04.10.02 (43)Compound Phosphates, etc. |
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(43.04)(Anhydrous Compound Anions With Hydroxyl or Halogen) |
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(43.04.10)Kraisslite Group |
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43.04.10.01 Kraisslite (Mn,Mg)24Zn3Fe(AsO3)2(AsO4)3(SiO4)6(OH)18 P 6322 6 2 2 |
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43.04.10.02 Ekatite! (Fe,Fe,Zn)12(OH)6[AsO3]6[AsO3,HOSiO3]2 P 63mc 6mm |
| Strunz Class: |
04.JB.75 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate |
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04.J - Arsenites, Antimonites, Bismuthites, Sulfites, |
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04.JB -Arsenites, antimonites, bismuthites; with additional anions, without H2O |
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04.JB.75 Ekatite! (Fe,Fe,Zn)12(OH)6[AsO3]6[AsO3,HOSiO3]2 P 63mc 6mm |
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Other Ekatite Information
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| References: |
NAME( AmMin, Vol 87, p 355) PHYS. PROP.(AmMin, Vol 87, p 355) OPTIC PROP.(AmMin, Vol 87, p 355) |
| 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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Print or Cut-and-Paste your Ekatite Specimen Label here :
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Ekatite
(Fe+++,Fe++,Zn)12(OH)6[AsO3]6[AsO3,HOSiO3]2
Dana No: 43.04.10.02 Strunz No: 04.JB.75
Locality:
Notes:
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