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Grimaldiite Mineral Data
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General Grimaldiite Information
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 Chemical Formula: |
Cr+++O(OH) |
| Composition: |
Molecular Weight = 85.00 gm |
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Chromium 61.17 % Cr 89.40 % Cr2O3 |
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Hydrogen 1.19 % H 10.60 % H2O |
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Oxygen 37.64 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
| Empirical Formula: |
CrO(OH) |
| Environment: |
Fine-grained intergrowth with other chromium oxide-hydroxide minerals in alluvial gravels. Trimorphous with bracewellite and guyanaite. |
| IMA Status: |
Approved IMA 1967 |
| Locality: |
Basin of the Merume River, Guyana. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Frank Saverio Grimaldi (1915- ), formerly Chief Chemist, U.S. Geological Survey. |
| Name Pronunciation: |
Grimaldiite + Pronunciation  |
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Grimaldiite Image |
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Images:
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Grimaldiite Crystallography
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| Axial Ratios: |
a:c = 1:4.50454 |
| Cell Dimensions: |
a = 2.973, c = 13.392, Z = 3; V = 102.51 Den(Calc)= 4.13 |
| Crystal System: |
Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3m |
| X Ray Diffraction: |
By Intensity(I/Io): 4.44(1), 2.407(0.3), 1.858(0.25), |
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Physical Properties of Grimaldiite
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| Color: |
Dark red, Reddish brown. |
| Density: |
4.11 |
| Diaphaneity: |
Opaque |
| Hardness: |
3.5-4.5 - Between Copper Penny and Fluorite-Apatite |
| Luster: |
Metallic |
| Streak: |
red |
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Optical Properties of Grimaldiite
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| Optical Data: |
NCalc= 2.22 - from Gladstone-Dale relationship (KC = 0.2953) where Ncalc=Dcalc*KC+1
NCalc= 2.21 - from Gladstone-Dale relationship (KC = 0.2953) where Ncalc=Dmeas*KC+1
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Calculated Properties of Grimaldiite
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| Electron Density: |
Bulk Density (Electron Density)=3.98 gm/cc
note: Specific Gravity of Grimaldiite =4.13 gm/cc.
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| Fermion Index: |
Fermion Index = 0.05
Boson Index = 0.95 |
| Photoelectric: |
PEGrimaldiite = 13.79 barns/electron
U=PEGrimaldiite x rElectron Density= 54.95 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Grimaldiite is Not Radioactive |
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Grimaldiite Classification
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| Dana Class: |
06.01.05.01 (06)Hydroxides and Oxides Containing Hydroxyl |
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(06.01)where X+++O OH |
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(06.01.05)Dana Group |
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06.01.05.01 Grimaldiite CrO(OH) R 3m 3 2/m |
| Strunz Class: |
04.FE.20 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate |
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04.F - Hydroxides (without V or U) |
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04.FE -Hydroxides with OH, without H2O; sheets of edge-sharing octahedra |
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04.FE.20 Grimaldiite CrO(OH) R 3m 3 2/m |
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04.FE.20 Heterogenite-2H CoO(OH) P 63/mmc 6/m 2/m 2/m |
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04.FE.20 Heterogenite-3R CoO(OH) R 3m 3 2/m |
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Other Grimaldiite Information
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| References: |
NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) |
| See Also: |
Links to other databases for Grimaldiite :
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 Grimaldiite Specimen Label here :
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Grimaldiite
Cr+++O(OH)
Dana No: 06.01.05.01 Strunz No: 04.FE.20
Locality:
Notes:
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