Mineralogy Database

Goethite Mineral Data

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General Goethite Information

Help on Chemical  Formula: Chemical Formula: Fe+++O(OH)
Help on Composition: Composition: Molecular Weight = 88.85 gm
   Iron      62.85 %  Fe   89.86 % Fe2O3
   Hydrogen   1.13 %  H    10.14 % H2O
   Oxygen    36.01 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Fe3+O(OH)
Help on Environment: Environment: Common in iron ore deposits.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1806
Help on Locality: Locality: Mesabi district, Minnesota, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after the German poet, J. W. Goethe (1749-1832).
Help on Name Pronunciation: Name Pronunciation: Goethite Say GOETHITE
Help on Synonym: Synonym: Acicular iron ore
  ICSD 28247
  Limonite
  Needle ironstone
  PDF 29-713
 

Goethite Image

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  Goethite

Comments: Stellate crystalline aggregates of acicular goethite crystals.
Location: Pribram, Bohemia, Czech Republic. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

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  Laubmannite   Goethite

Comments: Reddish brown goethite hosting radiating sprays of olive green laubmannite to 3 cm across.
Location: Buckeye Mountain, Polk County, Arkansas, USA. Scale: 10.5 x 7.5 cm.
© John Veevaert

Goethite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.4615:1:0.3034
Help on Cell Dimensions: Cell Dimensions: a = 4.596, b = 9.957, c = 3.021, Z = 4; V = 138.25 Den(Calc)= 4.27
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pbnm
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 4.18(1), 2.69(0.3), 2.452(0.25),
Help on Forms: Forms:

Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

Keyboard
S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

Forms: ( 0 1 0) ( 1 1 1) ( 1 0 0) ( 1 1 0) ( 0 1 1)

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Physical Properties of Goethite

Help on Cleavage: Cleavage: {010} Perfect, {100} Distinct
Help on Color: Color: Brown, Reddish brown, Yellowish brown, Brownish yellow, Ocher yellow.
Help on Density: Density: 3.3 - 4.3, Average = 3.8
Help on Diaphaneity: Diaphaneity: Subtranslucent to opaque
Help on Fracture: Fracture: Hackly - Jagged, torn surfaces, (e.g. fractured metals).
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Help on Habit: Habit: Reniform - "Kidney like" in shape (e.g.. hematite).
Help on Hardness: Hardness: 5-5.5 - Apatite-Knife Blade
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Adamantine - Silky
Help on Streak: Streak: yellowish brown
 

Optical Properties of Goethite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.14 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.014 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.322,KPDmeas= 0.3618,KC= 0.3175
Ncalc = 2.05 - 2.37
Help on Optical Data: Optical Data: Biaxial (-), a=2.26-2.275, b=2.393-2.409, g=2.398-2.515, bire=0.1380-0.2400, 2V(Calc)=20-78, 2V(Meas)=0-27. Dispersion r > v extreme.
Help on Pleochroism (x): Pleochroism (x): yellow or colorless.
Help on Pleochroism (y): Pleochroism (y): brownish yellow or ocher yellow.
Help on RL Anisotrophism: RL Anisotrophism: Distinct in bluish grays.
Help on RL Color: RL Color: Gray with bluish tint with yellow, red, brown internal reflections.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Goethite in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm   17.50   19.20 
   
 420 nm   16.70   18.30 
 440 nm   15.90   17.40 
 460 nm   15.20   16.70 
 480 nm   14.60   16.00 
 500 nm   14.10   15.50 
 520 nm   13.70   15.00 
 540 nm   13.30   14.60 
 560 nm   13.00   14.30 
 580 nm   12.80   14.00 
 600 nm   12.50   13.70 
 620 nm   12.40   13.50 
 640 nm   12.20   13.40 
 660 nm   12.00   13.20 
 680 nm   12.00   13.10 
 700 nm   11.90   13.00 
Calculated Relative Intensity Colors of Goethite in Air
Relative
Intensity
   0%   70% 100% 140% 210% 280% 350% 420% 490% 560% 630% 680%
R1                        
R2                        
 

Calculated Properties of Goethite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=4.13 gm/cc
note: Specific Gravity of Goethite =4.27 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEGoethite = 18.93 barns/electron
U=PEGoethite x rElectron Density= 78.24 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Goethite is Not Radioactive
 

Goethite Classification

Help on  Dana Class: Dana Class: 06.01.01.02 (06)Hydroxides and Oxides Containing Hydroxyl
  (06.01)where X+++O OH
  (06.01.01)Diaspore group (Orthorhombic, Pnma or Pnmd)
 
06.01.01.01 Diaspore AlO(OH) Pbnm 2/m 2/m 2/m
 
06.01.01.02 Goethite FeO(OH) Pbnm 2/m 2/m 2/m
 
06.01.01.03 Groutite MnO(OH) Pbnm 2/m 2/m 2/m
 
06.01.01.04 Montroseite (V,Fe,V)O(OH) Pbnm 2/m 2/m 2/m
 
06.01.01.05 Bracewellite CrO(OH) Pbnm 2/m 2/m 2/m
 
06.01.01.06 Tsumgallite! GaO(OH) Pbnm 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 04.FD.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.F - Hydroxides (without V or U)
  04.FD -Hydroxides with OH, without H2O; chains of edge-sharing octahedra
 
04.FD.10 Bracewellite CrO(OH) Pbnm 2/m 2/m 2/m
 
04.FD.10 Diaspore AlO(OH) Pbnm 2/m 2/m 2/m
 
04.FD.10 Guyanaite CrO(OH) Pnnm 2/m 2/m 2/m
 
04.FD.10 Groutite MnO(OH) Pbnm 2/m 2/m 2/m
 
04.FD.10 Goethite FeO(OH) Pbnm 2/m 2/m 2/m
 
04.FD.10 Montroseite (V,Fe,V)O(OH) Pbnm 2/m 2/m 2/m
 
04.FD.10 Tsumgallite! GaO(OH) Pbnm 2/m 2/m 2/m
 

Other Goethite Information

Help on See Also: See Also: Links to other databases for Goethite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Amethyst Galleries' Mineral Gallery
5 - Athena
6 - CalTech Mineral Spectroscopy
7 - EUROmin Project
8 - Ecole des Mines de Paris
9 - Franklin Minerals(Dunn)
10 - Franklin Minerals(Palache)
11 - GeoScienceWorld
12 - Glendale Community College
13 - Google Images
14 - Google Scholar
15 - Handbook of Mineralogy (MinSocAm)
16 - Handbook of Mineralogy (UofA)
17 - HyperPhysics
18 - MinDAT
19 - Mineralienatlas (Deutsch)
20 - Online Mineral Museum
21 - QUT Mineral Atlas
22 - Ruff.Info
23 - Scandinavian mineral gallery
24 - University of Colorado - Mineral Structure Data
25 - WWW-MINCRYST
26 - theimage

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

Goethite

Fe+++O(OH)
Dana No: 06.01.01.02 Strunz No: 04.FD.10
Locality:

 

Notes:

 

 


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