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Goethite

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Johann Wolfgang von Goethe
Formula:
α-Fe3+O(OH)
Colour:
brownish black, yellow-brown, reddish brown
Lustre:
Adamantine, Silky, Metallic, Dull
Hardness:
5 - 5½
Specific Gravity:
4.27 - 4.29
Crystal System:
Orthorhombic
Name:
Named in 1806 by Johann Georg Lenz in honor of the German poet, novelist, playwright, philosopher, politician, and geoscientist Johann Wolfgang von Goethe [August 28, 1749, Frankfurt, Germany – March 22, 1832, Weimar, Germany]. Goethe was Chief Minister of State of Weimar. (Portions of the Goethe mineral collection are reputedly held by the Goethe Society in New York, New York, USA.)
Diaspore Group.

Sulfidation of goethite into mackinawite and pyrrhotite is described by Wang et al. (2015); the process is inactive in the CH4 atmosphere but is triggered by the addition of CO2.

May crystallize from a precursor - a not approved species called 'proto-goethite'. May also form due to mineralization of lichen (Parmelia conspersa) thalli on metamorphics (e.g., gneisses), granites, feldspars.

Visit gemdat.org for gemological information about Goethite.


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Classification of GoethiteHide

Approved, 'Grandfathered' (first described prior to 1959)
4.00.

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
0 :
0 :
6.1.1.2

6 : HYDROXIDES AND OXIDES CONTAINING HYDROXYL
1 : XO(OH)
7.20.5

7 : Oxides and Hydroxides
20 : Oxides of Fe

Pronounciation of GoethiteHide

Pronounciation:
PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of GoethiteHide

Adamantine, Silky, Metallic, Dull
Transparency:
Opaque
Colour:
brownish black, yellow-brown, reddish brown
Streak:
yellowish brown, orange-yellow, ocher-yellow
Hardness:
5 - 5½ on Mohs scale
Hardness:
VHN100=667 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
Perfect
{010}; {100} less perfect.
Fracture:
Irregular/Uneven
Density:
4.27 - 4.29 g/cm3 (Measured)    4.18 g/cm3 (Calculated)

Optical Data of GoethiteHide

Type:
Biaxial (-)
RI values:
nα = 2.260 - 2.275 nβ = 2.393 - 2.409 nγ = 2.393 - 2.409
2V:
Calculated: 20°
Max Birefringence:
δ = 0.133 - 0.134
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Very High
Dispersion:
relatively strong r>v
Pleochroism:
Visible
Comments:
X = red b/yellow b = clear yellow
Y = red a/yellow c = brown-yellow
Z = red c/yellow a = orange-yellow

Chemical Properties of GoethiteHide

Formula:
α-Fe3+O(OH)
IMA Formula:
FeO(OH)
Common Impurities:
Mn

Crystallography of GoethiteHide

Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 4.608 Å, b = 9.956 Å, c = 3.0215 Å
Ratio:
a:b:c = 0.463 : 1 : 0.303
Unit Cell V:
138.62 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Prismatic [001] and striated [001]; also flattened into tablets or scales on {010}. Velvety aggregates of capillary crystals to acicular [001] and long prismatic forms often radially grouped. Massive, reniform, botryoidal, stalactitic. Bladed or columnar. Compact or fibrous concretionary nodules. Oolitic.

Crystallographic forms of GoethiteHide

Crystal Atlas:
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Goethite no.4 - Goldschmidt (1913-1926)
Goethite no.29 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by www.smorf.nl.

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Transparency
Opaque | Translucent | Transparent

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X-Ray Powder DiffractionHide

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Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacingIntensity
4.98 (12)
4.183 (100)
2.693 (35)
2.450 (50)
2.253 (14)
2.190 (18)
1.7192 (20)

Type Occurrence of GoethiteHide

Synonyms of GoethiteHide

Other Language Names for GoethiteHide

Varieties of GoethiteHide

AlumogoethiteAluminian Goethite
EhrenwerthiteA name for goethite pseudomorphs after Pyrite
SammetblendeA fuzzy variety of goethite with a velvety luster created by carpets of microscopic acicular crystals forming crusts or balls. The name is derived from the German word for "velvet" and is often used for this variety in Germany and Bohemia. A more modern s...
SammtblendeA fuzzy variety of goethite with a velvety luster created by carpets of microscopic acicular crystals forming crusts or balls. The name is derived from the German word for "velvet" and is often used for this variety in Germany and Bohemia. A more modern s...
SamtblendeA fuzzy variety of goethite with a velvety luster created by carpets of microscopic acicular crystals forming crusts or balls. The name is derived from the German word for "velvet" and is often used for this variety in Germany and Bohemia.

Common AssociatesHide

Associated Minerals Based on Photo Data:
Quartz564 photos of Goethite associated with Quartz on mindat.org.
Calcite450 photos of Goethite associated with Calcite on mindat.org.
Hematite245 photos of Goethite associated with Hematite on mindat.org.
Baryte167 photos of Goethite associated with Baryte on mindat.org.
Limonite150 photos of Goethite associated with Limonite on mindat.org.
Vanadinite149 photos of Goethite associated with Vanadinite on mindat.org.
Smoky Quartz132 photos of Goethite associated with Smoky Quartz on mindat.org.
Malachite130 photos of Goethite associated with Malachite on mindat.org.
Pyrite128 photos of Goethite associated with Pyrite on mindat.org.
Amethyst114 photos of Goethite associated with Amethyst on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

4.00.Microlite GroupIso. m3m (4/m 3 2/m) : Fd3m
4.00.Ferrotaaffeite-6N'3S(Be,Zn,Mg)FeAl4O8Trig.
4.00.Pyrochlore GroupA2Nb2(O,OH)6Z
4.00.Roméite Group
4.00.Ferrohögbomite-2N2S[(Fe2+,Mg,Zn,Al)3(Al,Ti,Fe3+)8O15(OH)]2Hex. 6mm : P63mc
4.00.Písekite-(Y)(Y,As,Ca,Fe,U)(Nb,Ti,Ta)O4
4.00.UM2004-19-O:AlCeGdZr(Gd,Ce)4Al2Zr4O17
4.00.UM2004-21-O:CaFeGdZrCa2Gd4Fe5ZrO15
4.00.UM2004-27-O:GdTiGd2Ti4O11
4.00.Mapiquiroite(Sr,Pb)(U,Y)Fe2(Ti,Fe3+,Cr3+)18O38Trig. 3 : R3
4.00.AlmeidaitePbZn2(Mn,Y)(Ti,Fe3+)18O37(OH,O)Trig. 3 : R3
4.00.VapnikiteCa2CaUO6Mon. 2/m

Related Minerals - Dana Grouping (8th Ed.)Hide

6.1.1.1DiasporeAlO(OH)Orth. mmm (2/m 2/m 2/m)
6.1.1.3GroutiteMn3+O(OH)Orth. mmm (2/m 2/m 2/m) : Pnma
6.1.1.4Montroseite(V3+,Fe3+)O(OH)Orth.
6.1.1.5BracewelliteCrO(OH)Orth. mmm (2/m 2/m 2/m)

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

7.20.1WüstiteFeOIso. m3m (4/m 3 2/m) : Fm3m
7.20.2MagnetiteFe2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
7.20.3MaghemiteFe3+2O3Iso. 4 3 2 : P41 3 2
7.20.4HematiteFe2O3Trig. 3m (3 2/m) : R3c
7.20.6Akaganeite(Fe3+,Ni2+)8(OH,O)16Cl1.25 · nH2OMon. 2/m
7.20.7FeroxyhyteFe3+O(OH)Hex.
7.20.8Lepidocrociteγ-Fe3+O(OH)Orth. mm2 : Cmc21
7.20.9FerrihydriteFe3+10O14(OH)2Trig.
7.20.10Amakinite(Fe2+,Mg)(OH)2Trig.
7.20.11MagnesioferriteMgFe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
7.20.12MuskoxiteMg7Fe4O13 · 10H2OTrig. 3m (3 2/m)
7.20.13SrebrodolskiteCa2Fe3+2O5Orth. mmm (2/m 2/m 2/m) : Pnma
7.20.14HercyniteFe2+Al2O4Iso. m3m (4/m 3 2/m) : Fd3m
7.20.15BrownmilleriteCa2(Al,Fe3+)2O5Orth. mm2

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
Iron ore

Goethite in petrologyHide

Common component of (items highlighted in red)

References for GoethiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Lenz, J.G. (1806) Göthit. In: Tabellen über das gesammte Mineralreich. Göpferdts, Jena, 46-46.
Posnjak, E., Merwin, H.E. (1919) The hydrated ferric oxides. American Journal of Science: 47: 311.
Spencer, L.J. (1919) Mineralogical characters of turite (=turgite) and some other iron-ores from Nova Scotia. Mineralogical Magazine: 18: 339.
Goldzstaub (1935) Bulletin soc. min., 58, 6.
Hoppe, W. (1940) Über die Kristallstruktur von α-AlOOH (Diaspor) und α-FeOOH (Nadeleisenerz). Zeitschrift für Kristallographie: 103: 73-89.
Palache, C., Berman, H., Frondel, C. (1944) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 680-685.
Szytula, A., Burewicz, A., Dimitrijevic, Z., Krasnicki, S., Rzany, H., Todorovic, J., Wanic, A., Wolski, W. (1968) Neutron diffraction studies of α-FeOOH. Physica Status Solidi: 26: 429-434.
Gualtieri, A.F., Venturelli, P. (1999) In situ study of the goethite-hematite phase transformation by real time synchrotron powder diffraction. American Mineralogist: 84: 895-904.
Frankel, R.B., Bazylinski, D.A. (2003) Biologically induced mineralization by bacteria. Reviews in Mineralogy and Geochemistry: 54: 95-114.
Burford, E.P., Kierans, M., Gadd, G.M. (2003) Geomycology: fungi in mineral substrata. Mycologist: 17(3): 98-107; DOI: 10.1017/S0269915X03003112
Yang, H., Lu, R., Downs, R.T., Costin, G. (2006) Goethite, α–FeO(OH), from single–crystal data. Acta Crystallographica: E62: i250-i252.
de Faria, D.L.A, Lopes, F.N. (2007) Heated goethite and natural hematite: can Raman spectroscopy be used to differentiate them? Vibrational Spectroscopy: 45: 117-121.
Wang, M., Chou, I-M., Lu, W., De Vivo, B. (2015) Effects of CH4 and CO2 on the sulfidization of goethite and magnetite: an in situ Raman spectroscopic study in high-pressure capillary optical cells at room temperature. European Journal of Mineralogy: 27(2): 193-201.

Internet Links for GoethiteHide

Localities for GoethiteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListShow