General Ferrihydrite Information Chemical Formula: |
Fe+++2O3•0.5(H2O) |
Composition: |
Molecular Weight = 168.70 gm |
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Iron 66.21 % Fe 94.66 % Fe2O3 |
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Hydrogen 0.60 % H 5.34 % H2O |
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Oxygen 33.19 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
Fe3+2O3•0.5(H2O) |
Environment: |
Secondary mineral in an oxidizing environment, strongly dependant on pH. |
IMA Status: |
Approved IMA 1973 |
Locality: |
Clara mine, Grube Clara, Germany Link to MinDat.org Location Data. |
Name Origin: |
Named for the composition as a hydrated ferric iron compound. |
Name Pronunciation: |
Ferrihydrite |
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Images:
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Ferrihydrite Crystallography Axial Ratios: |
a:c = 1:3.17567 |
Cell Dimensions: |
a = 2.96, c = 9.4, Z = 1; V = 71.33 Den(Calc)= 3.93 |
Crystal System: |
Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: P 31c |
X Ray Diffraction: |
By Intensity(I/Io): 2.45(1), 1.97(0.6), 2.25(0.6), |
Crystal Structure:
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Mouse
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| Physical Properties of Ferrihydrite Color: |
Yellow brown, Dark brown. |
Density: |
3.8 |
Habit: |
Aggregates - Made of numerous individual crystals or clusters. |
Habit: |
Microscopic Crystals - Crystals visible only with microscopes. |
Streak: |
yellowish brown |
| Optical Properties of Ferrihydrite Optical Data: |
NCalc= 2.24 - from Gladstone-Dale relationship (KC = 0.3163) where Ncalc=Dcalc*KC+1 |
NCalc= 2.2 - from Gladstone-Dale relationship (KC = 0.3163) where Ncalc=Dmeas*KC+1 | Calculated Properties of Ferrihydrite Electron Density: |
Bulk Density (Electron Density)=3.77 gm/cc |
note: Specific Gravity of Ferrihydrite =3.93 gm/cc. Fermion Index: |
Fermion Index = 0.01 |
Boson Index = 0.99 Photoelectric: |
PEFerrihydrite = 20.08 barns/electron |
U=PEFerrihydrite x rElectron Density= 75.77 barns/cc. Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) |
Ferrihydrite is Not Radioactive | Ferrihydrite Classification Dana Class: |
04.03.02.02 (04)Simple Oxides |
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(04.03)with a cation charge of 3+ (A+++2 O3) |
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(04.03.02)Dana Group |
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Strunz Class: |
04.FE.35 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate |
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04.F - Hydroxides (without V or U) |
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04.FE -Hydroxides with OH, without H2O; sheets of edge-sharing octahedra |
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| Other Ferrihydrite Information References: |
PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) |
See Also: |
Links to other databases for Ferrihydrite : |
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 - Online Mineral Museum 13 - QUT Mineral Atlas 14 - Ruff.Info Search for Ferrihydrite using: Visit our Advertisers for Ferrihydrite : A Bijoux Google Search for FerrihydriteAdam's Minerals Google Search for Ferrihydrite Cape Minerals Google Search for Ferrihydrite Dakota Matrix Minerals Google Search for Ferrihydrite Excalibur Mineral Corp. Google Search for Ferrihydrite Exceptional Minerals Google Search for Ferrihydrite John Betts Fine Minerals Search for Ferrihydrite McDougall Minerals Google Search for Ferrihydrite Mineral News Website Link Rock and Mineral Shows Google Search for Ferrihydrite Weinrich Minerals, Inc. Google Search for Ferrihydrite Ask about Ferrihydrite here : Print or Cut-and-Paste your Ferrihydrite Specimen Label here :
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