Goethite Mineral Data (original) (raw)

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

Click Here for Larger Goethite Image in a New Browser Window Images:

Click Here for Larger Goethite Image in a New Browser Window Images:

Click Here for Larger Goethite Image Goethite Laubmannite 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 - DipyramidalH-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
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Drag2 - Resize
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| | Forms:( 0 1 0) ( 1 1 1) ( 1 0 0) ( 1 1 0) ( 0 1 1) Warning: this large pop-up is very compute intensive and may not work well with some computers. | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

Click Here for Large Goethite Structure Window Crystal Structure:

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drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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| | Gualtieri A , Venturelli P , American Mineralogist , 84 (1999) p.895-904, In situ study of the goethite-hematite phase transformation by real time, synchrotron powder diffraction, Sample at T = 25 C View Additional jPOWD Structure files for Goethite [1] [2] [3] [4] [5] [6] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |

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 R 2 ∑ 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

RelativeIntensity 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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Ask about Goethite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
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Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Espa�ol

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: