Groutite (original) (raw)
A valid IMA mineral species - grandfathered
About GroutiteHide
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Colour:
Black, may be iridescent
Lustre:
Sub-Adamantine, Resinous, Waxy, Greasy, Dull
Crystal System:
Orthorhombic
Name:
Named in 1945 by John W. Gruner in honor of Frank Fitch Grout (August 1, January 24, 1880 Rockford, Illinois - August 1, 1958 Minneapolis, MN), petrologist, University of Minnesota, USA.
Co-Type Localities:
ⓘ Mahnomen pit, Ironton, Cuyuna North Range, Crow Wing County, Minnesota, USA
ⓘ Sagamore Mangan No. 2 pit, Riverton, Cuyuna North Range, Crow Wing County, Minnesota, USA
Unique IdentifiersHide
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Long-form identifier:
mindat:1:1:1756:1
62ada685-1b6f-4651-8369-a767bab2e044
IMA Classification of GroutiteHide
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Approved, 'Grandfathered' (first described prior to 1959)
Type description reference:
Classification of GroutiteHide
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4.FD.10
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
D : Hydroxides with OH, without H2O; chains of edge-sharing octahedra
6.1.1.3
6 : HYDROXIDES AND OXIDES CONTAINING HYDROXYL
1 : XO(OH)
7.18.8
7 : Oxides and Hydroxides
18 : Oxides of Mn
Mineral SymbolsHide
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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Gro | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Gro | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261–264 doi:10.1180/clm.2020.30 |
Pronunciation of GroutiteHide
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Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Sorry, your browser doesn't support HTML5 audio. | Jolyon Ralph | United Kingdom |
Physical Properties of GroutiteHide
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Sub-Adamantine, Resinous, Waxy, Greasy, Dull
Colour:
Black, may be iridescent
Hardness:
VHN100=630 - 711 kg/mm2 - Vickers
Cleavage:
Perfect
Perfect on {010}
Less perfect {100}
Fracture:
Irregular/Uneven, Splintery
Density:
4.144 g/cm3 (Measured) 4.172 g/cm3 (Calculated)
Optical Data of GroutiteHide
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RI values:
_n_α = 2.100 - 2.200 _n_γ = 2.100 - 2.200
δ = 0.000
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Optical Extinction:
Parallel
Reflectivity:
| Wavelength | R1 | R2 |
|---|---|---|
| 400nm | 13.7 % | 22.0% |
| 420nm | 13.4 % | 21.3% |
| 440nm | 13.3 % | 20.7% |
| 460nm | 13.1% | 20.2% |
| 480nm | 13.0% | 19.7% |
| 500nm | 13.0% | 19.4% |
| 520nm | 12.9% | 19.1% |
| 540nm | 12.9% | 19.0% |
| 560nm | 12.8% | 19.0% |
| 580nm | 12.7% | 18.7% |
| 600nm | 12.7% | 18.6% |
| 620nm | 12.7% | 18.5% |
| 640nm | 12.6% | 18.3% |
| 660nm | 12.5% | 18.2% |
| 680nm | 12.4% | 18.0% |
| 700nm | 12.4% | 17.9% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 22.0%.
R1 shown in black, R2 shown in red
Comments:
X = very dark brown to black; Y = yellowish brown.
Comments:
Strong pleochroism distinguishes groutite from manganite.
Chemistry of GroutiteHide
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Crystallography of GroutiteHide
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Crystal System:
Orthorhombic
Class (H-M):
m m m _(_2/_m_2/_m_2/m ) - Dipyramidal
Cell Parameters:
a = 4.560 Å, b = 10.700 Å, c = 2.870 Å
Ratio:
a:b:c = 0.426 : 1 : 0.268
Unit Cell V:
140.03 ų (Calculated from Unit Cell)
Morphology:
Wedge- or lens-shaped crystals. Type material showed: {110}, {120}, {130}, {010}, {100}, {111}, {021}, {134}
Twinning:
Reported. [Compare twinning in isostructural diaspore.]
Comment:
Non-standard space-group setting Pbnm.
Crystal StructureHide
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| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0011832 | Groutite | Wyckoff R W G (1963) Second edition. Interscience Publishers, New York, New York Crystal Structures 1 290-295 | 1963 | 0 | 293 | ||
| 0013941 | Groutite | Kohler T, Armbruster T, Libowitzky E (1997) Hydrogen bonding and Jahn-Teller distortion in groutite, alpha-MnOOH, and manganite, gamma-MnOOH, and their relations to the manganese dioxides ramsdellite and pyrolusite Journal of Solid State Chemistry 133 486-500 | 1997 | Nchwaning Mine, Kalahari manganese field, Republic of South Africa | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder DiffractionHide
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Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.349 Å | (9) |
| 4.195 Å | (100) |
| 3.471 Å | (10) |
| 2.8099 Å | (34) |
| 2.6743 Å | (29) |
| 2.5294 Å | (13) |
| 2.4288 Å | (4) |
| 2.3684 Å | (48) |
| 2.3076 Å | (17) |
| 2.2795 Å | (2) |
| 2.2297 Å | (2) |
| 2.2119 Å | (7) |
| 2.0078 Å | (5) |
| 1.9569 Å | (3) |
| 1.9372 Å | (4) |
| 1.7984 Å | (3) |
| 1.7833 Å | (2) |
| 1.7609 Å | (9) |
| 1.7354 Å | (6) |
| 1.6932 Å | (26) |
| 1.6055 Å | (18) |
| 1.5964 Å | (7) |
| 1.5604 Å | (3) |
| 1.5145 Å | (9) |
| 1.4848 Å | (1) |
| 1.4622 Å | (4) |
| 1.4491 Å | (4) |
| 1.4348 Å | (6) |
Comments:
ICDD 24-713 (Cayuna Range, Minnesota, USA) plus 51 lines of 1-4 intensity to 0.8227; see also ICDD 12-733 but with estimated intensities.
Geological EnvironmentHide
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Type Occurrence of GroutiteHide
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Co-Type Localities:
ⓘ Mahnomen pit, Ironton, Cuyuna North Range, Crow Wing County, Minnesota, USA
ⓘ Sagamore Mangan No. 2 pit, Riverton, Cuyuna North Range, Crow Wing County, Minnesota, USA
Place of Conservation of Type Material:
The Natural History Museum, London, England, number 1948,106.
National Museum of Natural History, Washington, D.C., USA, number 105004.
Geological Setting of Type Material:
Late stage mineralization in vugs in Banded Iron Formation (BIF)
Associated Minerals at Type Locality:
Reference:
Gruner, John W (1947) Groutite, HMnO2, a new mineral of the diaspore-goethite group. American Mineralogist: 32: 654-659.
Other Language Names for GroutiteHide
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Relationship of Groutite to other SpeciesHide
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Other Members of this group:
Common AssociatesHide
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Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat GroupingHide
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Fluorescence of GroutiteHide
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Not fluorescent in ultraviolet
Other InformationHide
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Thermal Behaviour:
Groutite is infusible and loses water on heating in air at temperatures above 200°C. Heating at 150°C in air for five days does not affect it.
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:
Manganese ore
Internet Links for GroutiteHide
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References for GroutiteHide
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Reference List:
Kohler, Thomas, Armbruster, Thomas, Libowitzky, Eugen (1997) Hydrogen Bonding and Jahn–Teller Distortion in Groutite,α-MnOOH, and Manganite,γ-MnOOH, and Their Relations to the Manganese Dioxides Ramsdellite and Pyrolusite. Journal of Solid State Chemistry, 133. 486-500 doi:10.1006/jssc.1997.7516
Bernardini, Simone, Bellatreccia, Fabio, Della Ventura, Giancarlo, Ballirano, Paolo, Sodo, Armida (2020) Raman spectroscopy and laser-induced degradation of groutellite and ramsdellite, two cathode materials of technological interest. RSC Advances, 10 (2). 923-929 doi:10.1039/c9ra08662e
Localities for GroutiteHide
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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 ListHide
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- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. 
- Good crystals or important locality for species. 
- World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.