Ferrihydrite Mineral Data + 
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- 4.3.2.1 Akdalaite (Al2O3)4·(H2O) P 6122,P 61 6 2 2
- 4.3.2.2 Ferrihydrite Fe2O3·0.5(H2O) P 31c 3 2/m
- 4.3.2.3 IMA2004-051! 5(Al2O3)·H2O P 63mc
- IV/F.09-10 Akdalaite (Al2O3)4·(H2O) P 6122,P 61 6 2 2
- IV/F.09-20 Ferrihydrite Fe2O3·0.5(H2O) P 31c 3 2/m
General Ferrihydrite Information |
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 Chemical Formula: |
Fe+++2O3·0.5(H2O) | ||
| Composition: |
Molecular Weight = 168.70 gm | ||
| Iron 66.21 % Fe 94.66 % Fe2O3 | |||
| Hydrogen 0.60 % H 5.34 % H2O | |||
| Oxygen 33.19 % O | |||
| ______ ______ | |||
| 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. | ||
Search for Ferrihydrite Images | |||
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Images:
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Ferrihydrite Crystallography |
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| 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), | ||
Physical Properties of Ferrihydrite |
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| 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 |
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| 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 |
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Calculated Properties of Ferrihydrite |
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| Electron Density: |
relectron=3.77 gm/cc |
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| Fermion Index |
Fermion Index = 0.01419 Boson Index = 0.98581 |
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| Photoelectric: |
PEFerrihydrite = 20.08 barns/electron |
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Ferrihydrite is Not Radioactive |
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Ferrihydrite Classification |
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| Dana Class: |
4.3.2.2 (4)Simple Oxides | ||
| (4.3)with a cation charge of 3+ (A+++2 O3) | |||
| (4.3.2)Dana Group | |||
| Strunz Class: |
IV/F.09-20 IV - Oxides | ||
| IV/F - Hydroxides and oxidic hydrates, water-bearing oxides with layered structure | |||
| IV/F.09 - Akdalaite - Ferrihydrite series | |||
Other Ferrihydrite Information |
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| 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 - Google Images 6 - Google Scholar 7 - Handbook of Mineralogy (MinSocAm) 8 - Handbook of Mineralogy (UofA) 9 - MinDAT 10 - MinMax(Deutsch) 11 - MinMax(English) 12 - Mineralienatlas (Deutsch) 13 - QUT Mineral Atlas 14 - Ruff.Info Search for Ferrihydrite using: Visit our Advertisers for Ferrihydrite : AA Mineral SpecimensB & L Fine Minerals Dan Weinrich Fine Minerals Dan Weinrich 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 The GeoZone Wrights Rock Shop Translate Ferrihydrite Mineral Data : Ask about Ferrihydrite here : Print or Cut-and-Paste your Ferrihydrite Specimen Label here :
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