Ferrihydrite Mineral Data

Ferrihydrite Mineral Data +

General Ferrihydrite Information

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

Images:

Image not yet available on Webmineral.com

Try searching images.google.com or Mindat Picture Gallary for mineral pictures. Caution: The images retrieved may not be appropriate.

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

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.45(1), 1.97(0.6), 2.25(0.6),

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:

r_electron=3.77 gm/cc
note: r_Ferrihydrite=3.93 gm/cc.

Fermion Index

Fermion Index = 0.01419
Boson Index = 0.98581

Photoelectric:

PE_Ferrihydrite= 20.08 barns/electron
U=PE_Ferrihydrite x r_electron= 75.77 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Ferrihydrite is Not Radioactive

Ferrihydrite Classification

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

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

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

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

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 - Crocoite.com Mineral Locations 4 - EUROmin Project 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 -École des Mines de Paris

Search for Ferrihydrite using:

[ALTAVISTA] [AOL] [About.com] [All-The-Web] [HotBot] [Ixquick] [LookSmart] [MAMMA] [MSN.COM] [Netscape] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Ferrihydrite :
AA Mineral Specimens
A-Rocks Auction
Adams Minerals
B and L Minerals
Dakota Matrix
Dan Weinrich Fine Minerals
Dan Weinrich Auctions
e-Rocks Auctions
Excalibur Minerals
Exceptional Minerals
Fabre Minerals
Greenside Minerals
John Betts Fine Minerals
Masons Minerals
Mineral News
Mineral of the Month Club
MineralsWeb Fine Minerals
Minernet.it
Rockshop.cz Kalat Fine Minerals
T G Fine Minerals
Wrights Rock Shop

Translate Ferrihydrite Mineral Data :

Ask about Ferrihydrite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Ferrihydrite Specimen Label here :

Ferrihydrite

Fe+++2O3·0.5(H2O)
Dana No: 4.3.2.2 Strunz No: IV/F.09-20
Locality:

Notes: