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Guyanaite

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Formula:
CrO(OH)
System:
Orthorhombic
Name:
Named in 1967 by Charles Milton, Daniel E. Appleman, Edward Ching-Te Chao, Frank Cuttita, Joseph I. Dinnin, Edward J. Dwornik, Margaret Hall, Blanche L. Ingram, and Harry J. Rose, Jr. for the country where the mineral was first found: Guyana / Guiana.
The β phase of CrO(OH). As with other Cr mineral species from the Merume River locality, such as bracewellite, grimaldiite, and mcconnellite, this species is NOT universally present in every specimen and verification of each specimen is required.

A nanophase Fe analogue is known as 'proto-goethite'.


Classification of Guyanaite

Approved
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
6.1.2.3

6 : HYDROXIDES AND OXIDES CONTAINING HYDROXYL
1 : XO(OH)
7.14.4

7 : Oxides and Hydroxides
14 : Oxides of Cr

Physical Properties of Guyanaite

Density:
4.53-4.81 g/cm3 (Calculated)

Optical Data of Guyanaite

Type:
Biaxial
Dispersion:
r > v extreme
Comments:
brown colours

Chemical Properties of Guyanaite

Formula:
CrO(OH)
Elements listed in formula:
Analytical Data:
Merume River, Guyana (water by stoichiometry) / Outokumpu, Finland (electron microprobe, mean of 7 analytical points, water by difference), wt.%
Ti2O3 0.86 / -
Al2O3 4.0 / 1.03
Fe2O3 4.4 / 1.47
Mn2O3 0.98 / -
V2O3 6.78 / -
Cr2O3 71.7 / 75.76
H2O+ 14.3 / 14.96

total 96.3 / 100.00
Common Impurities:
Fe,Al,V

Crystallography of Guyanaite

Crystal System:
Orthorhombic
Cell Parameters:
a = 4.857-4.862 Å, b = 4.295-4.314 Å, c = 2.951-2.958 Å
Ratio:
a:b:c = 1.131 : 1 : 0.687
Unit Cell Volume:
V 61.56 ų (Calculated from Unit Cell)
Z:
2
Comment:
Space group is P21nm or Pnnm (LP phase); HP phase: Pnnm
X-Ray Powder Diffraction Data:
d-spacingIntensity
3.224 (vvs)
2.432 (vs)
1.636 (s)
1.719 (ms)
1.609 (ms)
1.516 (ms)
2.524 (m)

Type Occurrence of Guyanaite

General Appearance of Type Material:
microcrystalline aggregates, alluvial grains; very rarely as prismatic crystals, up to 0.1 mm
Geological Setting of Type Material:
In an alluvial placer deposit, in fine-grained intergrowth with other chromium oxide-hydroxide minerals

Relationship of Guyanaite to other Species

4.FD.05SpertiniiteCu(OH)2
4.FD.10BracewelliteCrO(OH)
4.FD.10DiasporeAlO(OH)
4.FD.10GroutiteMn3+O(OH)
4.FD.10Montroseite(V3+,Fe2+,V4+)O(OH)
4.FD.10TsumgalliteGaOOH
4.FD.15ManganiteMn3+O(OH)
4.FD.20Yttrotungstite-(Y)Y(W,Fe,Si,Al,Ti)2(O,OH,H2O)9
4.FD.20Yttrotungstite-(Ce)CeW2O6(OH)3
4.FD.20Unnamed (Nd-analogue of Yttrotungstite-(Ce))(Nd,Ce,La)W2O6(OH)3
4.FD.25FrankhawthorneiteCu2Te6+O4(OH)2
4.FD.30KhiniteCu32+PbTe6+O6(OH)2
4.FD.30Khinite-3TPb2+Cu32+Te6+O6(OH)2
7.14.1EskolaiteCr2O3
7.14.2BracewelliteCrO(OH)
7.14.3GrimaldiiteCrO(OH)
7.14.5YimengiteK(Cr,Ti,Fe,Mg)12O19
7.14.6Mathiasite(Mg,Cr,Fe,Ca,K)2(Ti,Zr,Cr,Fe)5O12
7.14.7McconnelliteCu1+CrO2
7.14.8RedledgeiteBa(Ti64+Cr23+)O16
7.14.9HawthorneiteBaMgTi3Cr4Fe22+Fe23+O19
7.14.10ZincochromiteZnCr2O4
7.14.11WattersiteHg41+Hg2+O2(CrO4)
7.14.12ChromiteFe2+Cr2O4
7.14.13MagnesiochromiteMgCr23+O4

Other Names for Guyanaite

Name in Other Languages:
German:Guyanait
Spanish:Guyanaita

Other Information

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

References for Guyanaite

Reference List:
American Mineralogist: 62: 593

Milton, C., Appleman, D. E., Appleman, M. H., Chao, E. C. T., Cuttitta, F., Dinnin, J. I., Dwornik, E. J., Ingram, B. L. and Rose, H. J., Jr. (1976): Merumite, a complex assemblage of chromium minerals from Guyana. U.S. Geol. Surv. Prof. Paper: 887: 1-29 (+ 6 plates)

Jahn, S., Wunder, B., Koch-Müller, M., Tarrieu, L., Pöhle, M., Watenphul, A., Taran, M.N. (2012): Pressure-induced hydrogen bond symmetrisation in guyanaite, β-CrOOH: evidence from spectroscopy and ab initio simulations. European Journal of Mineralogy: 24(5): 839-850

Anthony, J.W., Bideaux, R.A., Bladh, K.W. and Nichols, M.C., Eds. Handbook of Mineralogy, Mineralogical Society of America, Chantilly, VA 20151-1110, USA. http://www.handbookofmineralogy.org/ (2016)

Internet Links for Guyanaite

mindat.org URL:
https://www.mindat.org/min-1783.html
Please feel free to link to this page.

Localities for Guyanaite

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.
(TL) indicates type locality for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
Finland
 
  • Eastern Finland Region
    • Outokumpu Cu-Co-Zn-Ni-Ag-Au ore field
Vuorelainen, Yrjö; Häkli, T.A.; Kataja, M. 1968. A hydrated oxide of chromium as a pseudumorph after eskolaite, Outokumpu, Finland. Bulletin of the Geological Society of Finland n:o 40, p. 125-129, illus.
Guyana (TL)
 
  • Mazaruni District
    • Kamakusa
Geol.Soc.Amer.,Progr.Ann. Meeting (1967) p. 151; MINERALOGICAL MAGAZINE, DECEMBER 1984, VOL. 48, PP. 560 2
  • Upper Takutu-Upper Essequibo Region
    • Omai
Voicu, G., & Bardoux, M. (2002). Geochemical behavior under tropical weathering of the Barama–Mazaruni greenstone belt at Omai gold mine, Guiana Shield. Applied geochemistry, 17(3), 321-336.
Russia
 
  • Urals Region
    • Middle Urals
      • Permskaya Oblast'
        • Gornozavodskii area
          • Saranovskaya Village (Sarany)
Суставов, С. Г., Шагалов, Е. С., Нурмухаметов, Ф. З., & Главатских, С. П. (2012). ПЕРВАЯ НАХОДКА В РОССИИ ОКСИГИДРАТОВ ХРОМА-ГРИМАЛЬДИТА И ГВИАНАИТА В ЮЖНО-САРАНОВСКОМ ХРОМИТОВОМ МЕСТОРОЖДЕНИИ. Литосфера, (3), 154-159.
USA
 
  • Utah
    • San Juan Co.
Schulze, D. J., Flemming, R. L., Shepherd, P. H., & Helmstaedt, H. (2014). Mantle-derived guyanaite in a Cr-omphacitite xenolith from Moses Rock diatreme, Utah. American Mineralogist, 99(7), 1277-1283.
Mineral and/or Locality  
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