Guyanaite Mineral Data

General Guyanaite Information

Chemical Formula:

CrO(OH)

Composition:

Molecular Weight = 85.00 gm

Chromium 61.17 % Cr 89.40 % Cr₂O₃

Hydrogen 1.19 % H 10.60 % H₂O

Oxygen 37.64 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CrO(OH)

Environment:

Fine-grained intergrowth with other chromium oxide-hydroxide minerals. Trimorphous with bracewellite and grimaldiite.

IMA Status:

Approved IMA 1967

Locality:

Merume River and its tributaries, Mazaruni district, Guyana. Link to MinDat.org Location Data.

Name Origin:

Named for the localtiy.

Name Pronunciation:

Guyanaite + Pronunciation

Synonym:

ICSD 2257

PDF 25-1437

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Guyanaite Crystallography

Axial Ratios:

a:b:c =1.1308:1:0.6887

Cell Dimensions:

a = 4.857, b = 4.295, c = 2.958, Z = 2; V = 61.71 Den(Calc)= 4.57

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pnnm

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.224(1), 1.636(0.4), 2.432(0.4),

Crystal Structure:

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Christensen N , Hansen P , Lehmann M S , Journal of Solid State Chemistry , 19 (1976) p.299-304, Isotope effects in the bonds of beta-CrOOH and beta-CrOOD, Locality: synthetic

Physical Properties of Guyanaite

Color:

Greenish brown, Golden brown, Reddish brown.

Density:

4.53

Streak:

brown

Optical Properties of Guyanaite

Gladstone-Dale:

CI meas= 0.327 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.333 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1969,KPDmeas= 0.1987,KC= 0.2953
Ncalc = 2.34 - 2.35

Optical Data:

Biaxial (?), b=1.9

Calculated Properties of Guyanaite

Electron Density:

Bulk Density (Electron Density)=4.37 gm/cc
note: Specific Gravity of Guyanaite =4.53 gm/cc.

Fermion Index:

Fermion Index = 0.05
Boson Index = 0.95

Photoelectric:

PE_Guyanaite= 13.79 barns/electron
U=PE_Guyanaite x rElectron Density= 60.27 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Guyanaite is Not Radioactive

Guyanaite Classification

Dana Class:

06.01.02.03 (06)Hydroxides and Oxides Containing Hydroxyl

(06.01)where X+++O OH

(06.01.02)Boehmite Group

06.01.02.01 Boehmite AlO(OH) Amam 2/m 2/m 2/m

06.01.02.02 Lepidocrocite FeO(OH) Amam 2/m 2/m 2/m

06.01.02.03 Guyanaite CrO(OH) Pnnm 2/m 2/m 2/m

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 Guyanaite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Guyanaite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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

Guyanaite

CrO(OH)
Dana No: 06.01.02.03 Strunz No: 04.FD.10
Locality:

Notes: