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Eskolaite Mineral Data
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General Eskolaite Information
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 Chemical Formula: |
Cr2O3 |
| Composition: |
Molecular Weight = 151.99 gm |
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Chromium 68.42 % Cr 100.00 % Cr2O3 |
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Oxygen 31.58 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
| Empirical Formula: |
Cr2O3 |
| Environment: |
In chromium-rich termolite skarns, metaquartzites, and chlorite veins. Rare component of chondrite meteorites. |
| IMA Status: |
Valid Species (Pre-IMA) 1958 |
| Locality: |
Outokumpu, Karelia, Finland. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Pentti Eelis Eskola (1883-1964), of the University of Helsinki, Helsinki, Finland. |
| Name Pronunciation: |
Eskolaite + Pronunciation  |
| Synonym: |
ICSD 201102 |
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PDF 38-1479 |
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Eskolaite Image |
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Images:
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Eskolaite Crystallography
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| Axial Ratios: |
a:c = 1:2.74304 |
| Cell Dimensions: |
a = 4.958, c = 13.6, Z = 6; V = 289.52 Den(Calc)= 5.23 |
| Crystal System: |
Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3c |
| X Ray Diffraction: |
By Intensity(I/Io): 1.67(1), 2.67(0.97), 3.63(0.96), |
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Physical Properties of Eskolaite
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| Cleavage: |
None |
| Color: |
Black, Dark green. |
| Density: |
5.18 |
| Diaphaneity: |
Opaque |
| Fracture: |
Brittle - Uneven - Very brittle fracture producing uneven fragments. |
| Habit: |
Hexagonal - Six-sided crystal shape in cross-section or habit. |
| Habit: |
Platy - Sheet forms (e.g. micas). |
| Habit: |
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). |
| Hardness: |
8-8.5 - Between Topaz and Chrysoberyl |
| Luster: |
Metallic |
| Streak: |
green |
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Optical Properties of Eskolaite
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| Dichroism (e): |
emerald green. |
| Dichroism (w): |
olive green. |
| Optical Data: |
Uniaxial (?). |
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NCalc= 2.52 - from Gladstone-Dale relationship (KC = 0.29) where Ncalc=Dcalc*KC+1
NCalc= 2.5 - from Gladstone-Dale relationship (KC = 0.29) where Ncalc=Dmeas*KC+1 |
| RL Color: |
Gray with emerald green internal reflections. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Eskolaite in Air
| λ |
R |
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∑ R(λ) |
| 400 nm |
24.50 |
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| 420 nm |
23.60 |
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| 440 nm |
22.70 |
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| 460 nm |
22.10 |
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| 480 nm |
22.00 |
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| 500 nm |
21.80 |
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| 520 nm |
21.50 |
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| 540 nm |
21.00 |
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| 560 nm |
20.50 |
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| 580 nm |
20.10 |
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| 600 nm |
19.80 |
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| 620 nm |
19.70 |
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| 640 nm |
19.60 |
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| 660 nm |
19.50 |
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| 680 nm |
19.50 |
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| 700 nm |
19.50 |
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Calculated Relative Intensity Colors of Eskolaite in Air
Relative
Intensity |
0% |
50% |
100% |
150% |
200% |
250% |
300% |
350% |
400% |
440% |
| R |
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Calculated Properties of Eskolaite
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| Electron Density: |
Bulk Density (Electron Density)=4.96 gm/cc
note: Specific Gravity of Eskolaite =5.23 gm/cc.
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| Fermion Index: |
Fermion Index = 0.06
Boson Index = 0.94 |
| Photoelectric: |
PEEskolaite = 15.66 barns/electron
U=PEEskolaite x rElectron Density= 77.59 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Eskolaite is Not Radioactive |
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Eskolaite Classification
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| Dana Class: |
04.03.01.03 (04)Simple Oxides |
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(04.03)with a cation charge of 3+ (A+++2 O3) |
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(04.03.01)Corundum-Hematite group (Rhombohedral: R-3c) |
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04.03.01.01 Corundum Al2O3 R 3c 3 2/m |
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04.03.01.02 Hematite Fe2O3 R 3c 3 2/m |
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04.03.01.03 Eskolaite Cr2O3 R 3c 3 2/m |
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04.03.01.04 Karelianite V2O3 R 3c 3 2/m |
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04.03.01.05 Tistarite! Ti2O3 R 3c 3 2/m |
| Strunz Class: |
04.CB.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate |
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04.C - Metal:Oxygen = 2:3, 3:5, and Similar |
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04.CB -With medium-sized cations |
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04.CB.05 Auroantimonate* AuSbO3 Ortho ? Ortho |
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04.CB.05 Geikielite MgTiO3 R 3 3 |
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04.CB.05 Brizziite-III NaSbO3 R 3 3 |
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04.CB.05 Brizziite-VII NaSbO3 R 3 3 |
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04.CB.05 Ecandrewsite (Zn,Fe,Mn)TiO3 R 3 3 |
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04.CB.05 Corundum Al2O3 R 3c 3 2/m |
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04.CB.05 Eskolaite Cr2O3 R 3c 3 2/m |
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04.CB.05 Hematite Fe2O3 R 3c 3 2/m |
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04.CB.05 Karelianite V2O3 R 3c 3 2/m |
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04.CB.05 Ilmenite FeTiO3 R 3 3 |
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04.CB.05 Melanostibite Mn(Sb,Fe)O3 R 3 3 |
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04.CB.05 Pyrophanite MnTiO3 R 3 3 |
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04.CB.05 Romanite* (Fe,U,Pb)2(Ti,Fe)O4 Trig ? Trig |
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04.CB.05 Tistarite! Ti2O3 R 3c 3 2/m |
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Other Eskolaite Information
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| References: |
NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3) |
| See Also: |
Links to other databases for Eskolaite :
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
15 - University of Colorado - Mineral Structure Data
16 - WWW-MINCRYST
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Print or Cut-and-Paste your Eskolaite Specimen Label here :
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Eskolaite
Cr2O3
Dana No: 04.03.01.03 Strunz No: 04.CB.05
Locality:
Notes:
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