General Stilpnomelane Information Chemical Formula: |
K(Fe++,Mg,Fe+++)8(Si,Al)12(O,OH)27•n(H2O) |
Composition: |
Molecular Weight = 1,247.57 gm |
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Potassium 3.13 % K |
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Magnesium 2.73 % Mg |
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Aluminum 4.33 % Al |
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Iron 29.54 % Fe |
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Silicon 22.51 % Si |
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Hydrogen 0.57 % H |
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Oxygen 37.19 % O |
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100.00 % |
Empirical Formula: |
KFe2+4.3Mg1.4Fe3+2.3Si10Al2O24(OH)3·2(H2O) |
Environment: |
Commonly associated with iron ores. |
IMA Status: |
Valid Species (Pre-IMA) 1827 |
Locality: |
Moravia of Czechoslovakia at Sternberg in a bed of limonite. Link to MinDat.org Location Data. |
Name Origin: |
From the Greek for "shining" and "black", in allusion to its luster and color. |
Name Pronunciation: |
Stilpnomelane + Pronunciation |
Synonym: |
Ferristilpnomelane - high Fe+++ |
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Ferrostilpnomelane - Low Fe+++ |
| | Stilpnomelane Image
Images:
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Stilpnomelane Crystallography Axial Ratios: |
a:b:c =1:1:0.8073 |
Cell Dimensions: |
a = 21.8, b = 21.8, c = 17.6, Z = 6; alpha = 125.03°, beta = 95.98°, gamma = 120° V = 5,899.18 Den(Calc)= 2.11 |
Crystal System: |
Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1 |
X Ray Diffraction: |
By Intensity(I/Io): 2.55(1), 4.16(1), 12.3(1), |
Crystal Structure:
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Mouse
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| Physical Properties of Stilpnomelane Cleavage: |
{001} Perfect |
Color: |
Brown red, Green, Golden brown, Black. |
Density: |
2.77 - 2.96, Average = 2.86 |
Diaphaneity: |
Subtranslucent to opaque |
Fracture: |
Brittle - Generally displayed by glasses and most non-metallic minerals. |
Habit: |
Fibrous - Crystals made up of fibers. |
Habit: |
Foliated - Two dimensional platy forms. |
Habit: |
Platy - Sheet forms (e.g. micas). |
Hardness: |
3 - Calcite |
Luminescence: |
Non-fluorescent. |
Luster: |
Vitreous - Dull |
Streak: |
gray white |
| Optical Properties of Stilpnomelane Optical Data: |
Biaxial (-), a=1.543-1.634, b=1.576-1.745, g=1.576-1.745, bire=0.0330-0.1110, 2V(Calc)=0, 2V(Meas)=0-40. Dispersion none. |
Pleochroism (x): |
pale yellow, golden yellow, pale brown, or colorless. |
Pleochroism (y): |
deep brown, nearly black, chestnut brown, deep yellowish brown, or light greenish yellow. |
Pleochroism (z): |
deep brown, nearly black, chestnut brown, deep yellowish brown, or light greenish yellow. |
| Calculated Properties of Stilpnomelane Electron Density: |
Bulk Density (Electron Density)=2.46 gm/cc |
note: Specific Gravity of Stilpnomelane =2.51 gm/cc. Fermion Index: |
Fermion Index = 0.01 |
Boson Index = 0.99 Photoelectric: |
PEStilpnomelane = 10.10 barns/electron |
U=PEStilpnomelane x relectron= 24.89 barns/cc. Radioactivity: |
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GRapi = 44.41 (Gamma Ray American Petroleum Institute Units)
Estimated Radioactivity from Stilpnomelane - barely detectable | Stilpnomelane Classification Dana Class: |
74.01.01.01 (74)Phyllosilicate Modulated Layers |
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(74.01)with joined islands |
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(74.01.01)Stilpnomelane group |
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Strunz Class: |
09.EG.40 09 - SILICATES (Germanates) |
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09.E - Phyllosilicates |
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09.EG -Double nets with 6-membered and larger rings |
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| Other Stilpnomelane Information References: |
NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990) |
See Also: |
Links to other databases for Stilpnomelane : |
1 - Am. Min. Crystal Structure Database 2 - Athena 3 - EUROmin Project 4 - Ecole des Mines de Paris 5 - GeoScienceWorld 6 - Google Images 7 - Google Scholar 8 - Handbook of Mineralogy (MinSocAm) 9 - Handbook of Mineralogy (UofA) 10 - MinDAT 11 - Mineralienatlas (Deutsch) 12 - Minerals in Thin Section-University of North Carolina 13 - Minerals in Thin Sections-Humboldt State 14 - Online Mineral Museum 15 - QUT Mineral Atlas 16 - Ruff.Info Search for Stilpnomelane using: Visit our Advertisers for Stilpnomelane : A Bijoux Google Search for StilpnomelaneAdam's Minerals Google Search for Stilpnomelane Cape Minerals Google Search for Stilpnomelane Dakota Matrix Minerals Google Search for Stilpnomelane Excalibur Mineral Corp. Google Search for Stilpnomelane Exceptional Minerals Google Search for Stilpnomelane John Betts Fine Minerals Search for Stilpnomelane McDougall Minerals Google Search for Stilpnomelane Mineral News Website Link Rock and Mineral Shows Google Search for Stilpnomelane Weinrich Minerals, Inc. Google Search for Stilpnomelane Ask about Stilpnomelane here : Print or Cut-and-Paste your Stilpnomelane Specimen Label here :
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