Psilomelane Mineral Data + 
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- 7.9.2.0 Psilomelane ? (Ba,H2O)2Mn5O10 A2/m 2/m
- 7.9.2.1 Romanechite (Ba,H2O)2(Mn,Mn)5O10 C 2/m 2/m
General Psilomelane Information |
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 Chemical Formula: |
(Ba,H2O)2Mn5O10 | ||
| Composition: |
Molecular Weight = 590.03 gm | ||
| Barium 23.27 % Ba 25.99 % BaO | |||
| Manganese 46.56 % Mn 66.89 % Mn2O3 | |||
| Hydrogen 0.34 % H 3.05 % H2O | |||
| Oxygen 29.83 % O | |||
| ______ ______ | |||
| 100.00 % 95.93 % = TOTAL OXIDE | |||
| Empirical Formula: |
Ba·(H2O)Mn3+5O10 | ||
| Environment: |
General term for hard, black Mn oxides. Romanechite is one of the most common species. | ||
| IMA Status: |
Discredited IMA 1982 | ||
| Locality: |
Common world wide. Link to MinDat.org Location Data. | ||
| Name Origin: |
Named in 1758 from the Greek psilos - "smooth" and melas - "black." | ||
Psilomelane Image | |||
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Images:
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Psilomelane Crystallography |
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| Axial Ratios: |
a:b:c =3.3194:1:4.809 | ||
| Cell Dimensions: |
a = 9.56, b = 2.88, c = 13.85, Z = 2; beta = 92.5° V = 380.97 Den(Calc)= 5.14 | ||
| Crystal System: |
Monoclinic - PrismaticH-M Symbol (2/m) Space Group: A2/m | ||
Physical Properties of Psilomelane |
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| Cleavage: |
None | ||
| Color: |
Iron black, Dark steel gray. | ||
| Density: |
4.4 - 4.7, Average = 4.55 | ||
| Diaphaniety: |
Opaque | ||
| Fracture: |
Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. | ||
| Habit: |
Botryoidal - "Grape-like" rounded forms (e.g.. malachite). | ||
| Habit: |
Mammillary - Larger "breast-like" rounded forms resembling botryoidal (e.g. malachite). | ||
| Habit: |
Reniform - "Kidney like" in shape (e.g.. hematite). | ||
| Hardness: |
5-6 - Between Apatite and Orthoclase | ||
| Luminescence: |
None. | ||
| Luster: |
Sub Metallic | ||
| Magnetism: |
Nonmagnetic | ||
| Streak: |
brownish black | ||
Optical Properties of Psilomelane |
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| Optical Data: |
NCalc= 2.26 - from Gladstone-Dale relationship (KC = 0.245) where Ncalc=Dcalc*KC+1 NCalc= 2.11 - from Gladstone-Dale relationship (KC = 0.245) where Ncalc=Dmeas*KC+1 |
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Calculated Properties of Psilomelane |
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| Electron Density: |
relectron=4.72 gm/cc |
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| Fermion Index |
Fermion Index = 0.04162 Boson Index = 0.95838 |
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| Photoelectric: |
PEPsilomelane = 114.11 barns/electron |
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Psilomelane is Not Radioactive |
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Psilomelane Classification |
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| Dana Class: |
7.9.2.0 (7)Multiple Oxides | ||
| (7.9)where A B (O)2 | |||
| (7.9.2)Dana Group | |||
| Strunz Class: |
IV/X.00-00 IV - Oxides | ||
| IV/X - Unclassified Strunz Oxides | |||
| IV/X.00 - Oxide | |||
Other Psilomelane Information |
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| References: |
NAME( Duda&Rejl90) PHYS. PROP.(Mason68) | ||
| See Also: |
Links to other databases for Psilomelane : 1 -Am. Min. Crystal Structure Database 2 - Amethyst Galleries' Mineral Gallery 3 -Athena 4 - Crocoite.com Mineral Locations 5 - Franklin Minerals(Palache) 6 - Glendale Community College 7 -Google Images 8 -Google Scholar 9 -MinDAT 10 -MinMax(Deutsch) 11 -MinMax(English) 12 -Mineralienatlas (Deutsch) 13 - Minerals of Wisconsin 14 -QUT Mineral Atlas 15 - WWW-MINCRYST Search for Psilomelane using: Visit our Advertisers for Psilomelane : AA Mineral SpecimensB & L Fine Minerals Dan Weinrich Fine Minerals Dan Weinrich Auctions e-Rocks Auctions Excalibur Minerals Exceptional Minerals Fabre Minerals Greenside Minerals Heliodor John Betts Fine Minerals Mason's Minerals Mineral News Mineral of the Month Club MineralsWeb Fine Minerals T G Fine Minerals Wrights Rock Shop Translate Psilomelane Mineral Data : Ask about Psilomelane here : Print or Cut-and-Paste your Psilomelane Specimen Label here :
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