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Cryptomelane Mineral Data + |
General Cryptomelane Information |
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| K(Mn++++,Mn++)8O16 | |||
| Molecular Weight = 734.59 gm | |||
| Potassium 5.32 % K 6.41 % K2O | |||
| Manganese 59.83 % Mn 19.31 % MnO / 71.01 % MnO2 | |||
| Oxygen 34.85 % O | |||
| ______ ______ | |||
| 100.00 % 96.73 % = TOTAL OXIDE | |||
| KMn4+6Mn2+2O16 | |||
| Commonest of the hard, black, fine-grained manganese oxides formerly called psilomelane. | |||
| Valid Species (Pre-IMA) 1942 | |||
| Chindwara, India. Link to MinDat.org Location Data. | |||
| From the Greek for hidden and black, as the identity of this common, black mineral is lost in the group of other black Mn-bearing oxides. | |||
| Psilomelane | |||
Cryptomelane Image | |||
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Cryptomelane Crystallography |
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| a:b:c =3.3993:1:3.4513 | |||
| a = 9.79, b = 2.88, c = 9.94, Z = 1; beta = 90.62° V = 280.24 Den(Calc)= 4.35 | |||
| Monoclinic - PrismaticH-M Symbol (2/m) Space Group: I2/m | |||
| By Intensity(I/Io): 2.399(1), 1.654(0.8), 3.11(0.8), | |||
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Mouse |
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Physical Properties of Cryptomelane |
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| Black, Gray, Blue gray. | |||
| 4.36 | |||
| Opaque | |||
| Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). | |||
| Botryoidal - "Grape-like" rounded forms (e.g.. malachite). | |||
| Cryptocrystalline - Occurs as crystals too small to distinguish with the naked eye. | |||
| Massive - Uniformly indistinguishable crystals forming large masses. | |||
| 6-6.5 - Orthoclase-Pyrite | |||
| Sub Metallic | |||
| brownish black | |||
Calculated Properties of Cryptomelane |
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relectron=4.11 gm/cc |
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| Fermion Index = 0.00017 Boson Index = 0.99983 |
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PECryptomelane = 16.25 barns/electron |
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| GRapi = 72.57 (Gamma Ray American Petroleum Institute Units) Estimated Radioactivity from Cryptomelane |
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Cryptomelane Classification |
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| 7.9.1.2 (7)Multiple Oxides | |||
| (7.9)where A B (O)2 | |||
| (7.9.1)Cryptomelane Group (Hard black, fine-grained) | |||
| IV/D.08-20 IV - Oxides | |||
| IV/D - Oxides with metal : oxygen = 1:2 (MO2 and related compounds) | |||
| IV/D.08 - Cryptomelane group | |||
Other Cryptomelane Information |
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| NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) | |||
| Links to other databases for Cryptomelane : 1 -Am. Min. Crystal Structure Database 2 -Athena 3 - Crocoite.com Mineral Locations 4 - Franklin Minerals(Dunn) 5 -Google Images 6 -Google Scholar 7 -Handbook of Mineralogy (UofA) 8 -MinDAT 9 -MinMax(Deutsch) 10 -MinMax(English) 11 -Mineralienatlas (Deutsch) 12 -QUT Mineral Atlas 13 - WWW-MINCRYST 14 -theimage 15 -École des Mines de Paris Search for Cryptomelane using: Visit our Advertisers for Cryptomelane : Translate Cryptomelane Mineral Data : Ask about Cryptomelane here : Print or Cut-and-Paste your Cryptomelane Specimen Label here :
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