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Omongwaite Mineral Data
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General Omongwaite Information
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 Chemical Formula: |
Na2Ca5(SO4)6•3H2O |
| Composition: |
Molecular Weight = 880.31 gm |
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Potassium 2.62 % K 3.16 % K2O |
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Sodium 3.84 % Na 5.17 % Na2O |
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Calcium 21.67 % Ca 30.32 % CaO |
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Hydrogen 0.69 % H 6.14 % H2O |
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Sulfur 22.11 % S 55.21 % SO3 |
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Oxygen 49.07 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
| Empirical Formula: |
Na1.47K0.59Ca4.76S6.07O24•3(H2O) |
| Environment: |
Found in inclusions in gypsum crystals in recent salt lake deposits. Related to bassanite. |
| IMA Status: |
Approved IMA 2005 (Dana # Added) |
| Locality: |
Omongwa (salt) pan, near Aminuis, 140 km SSE of Gobabis, southwestern Kalahari, Namibia. Link to MinDat.org Location Data. |
| Name Origin: |
Named for the locality |
| Synonym: |
IMA2003-054b |
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Omongwaite Crystallography
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| Axial Ratios: |
a:b:c =1.7356:1:0.9181 |
| Cell Dimensions: |
a = 12.08, b = 6.96, c = 6.39, Z = 1; beta = 90.2° V = 537.25 Den(Calc)= 2.72 |
| Crystal System: |
Monoclinic - Sphenoidal H-M Symbol (2) Space Group: C 2 |
| X Ray Diffraction: |
By Intensity(I/Io): 3.014(1), 2.82(0.65), 3.019(0.51),6.028(0.4), 2.824(0.34), 3.484(0.29), 1.855(0.24), 1.853(0.23), |
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Physical Properties of Omongwaite
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| Color: |
White. |
| Diaphaneity: |
Transparent |
| Habit: |
Inclusions - Generally found as inclusions in other minerals. |
| Habit: |
Pseudo Hexagonal - Crystals show a hexagonal outline. |
| Luster: |
Vitreous (Glassy) |
| Streak: |
white |
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Optical Properties of Omongwaite
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| Optical Data: |
NCalc= 1.54 - from Gladstone-Dale relationship (KC = 0.1983) where Ncalc=Dcalc*KC+1
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Calculated Properties of Omongwaite
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| Electron Density: |
Bulk Density (Electron Density)=2.73 gm/cc
note: Specific Gravity of Omongwaite =2.72 gm/cc.
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| Fermion Index: |
Fermion Index = 0.002190571
Boson Index = 0.997809429 |
| Photoelectric: |
PEOmongwaite = 4.31 barns/electron
U=PEOmongwaite x relectron= 11.77 barns/cc.
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| Radioactivity: |
GRapi = 37.94 (Gamma Ray American Petroleum Institute Units)
Concentration of Omongwaite per GRapi unit = 2.64 (%)
Estimated Radioactivity from Omongwaite  - barely detectable
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Omongwaite Classification
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| Dana Class: |
29.04.07.02 (29)Hydrated Acid and Sulfates |
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(29.04)where (A+)2 Bn (XO4)p � x(H2O) |
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(29.04.07)Dana Group |
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29.04.07.01 Gorgeyite K2Ca5(SO4)6•(H2O) C 2/c 2/m |
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29.04.07.02 Omongwaite! Na2Ca5(SO4)6•3H2O C 2 2 |
| Strunz Class: |
07.CD.65 07 - SULFATES (SELENATES, TELLURATES) |
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07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O |
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07.CD -With only large cations |
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07.CD.65 Omongwaite! Na2Ca5(SO4)6•3H2O C 2 2 |
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Other Omongwaite Information
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| References: |
NAME( MinMag, v72:1307) PHYS. PROP.(MinMag, v72:1307) |
| See Also: |
Links to other databases for Omongwaite :
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 Omongwaite Specimen Label here :
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Omongwaite
Na2Ca5(SO4)6•3H2O
Dana No: 29.04.07.02 Strunz No: 07.CD.65
Locality:
Notes:
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