Chromite Mineral Data

General Chromite Information
Help on Chemical Formula: Chemical Formula: Fe++Cr2O4
Help on Composition: Composition: Molecular Weight = 223.84 gm
   Chromium  46.46 %  Cr   67.90 % Cr2O3
   Iron      24.95 %  Fe   32.10 % FeO
   Oxygen    28.59 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Fe2+Cr2O4
Help on Environment: Environment: Cummulate mineral found in ultramafic portions of layered mafic intrusions. Common in meteorites.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1845
Help on Locality: Locality: Bastide de la Carrade, Gassin, Var, France. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after its chemical composition.
Help on Synonym: Synonym: Chrome iron ore
  Chromic iron
  Ferrichromite-magnetic, altered
  ICSD 20819
  PDF 34-140
 

Chromite Image

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Chromite   Antigorite

Comments: Chromite veins in yellow to green antigorite with picrolite, chromian antigorite and dolomite (polished section).
Location: Wood's Mine, near 'Texas', Little Britain Township, Lancaster County, Pennsylvania, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species
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Chromite   Theophrastite

Comments: Green pearly scaly theophrastite coatings on massive dark chromite.
Location: Vermion Region, near Thessaloniki, Kedriki Makedhonia, Greece. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Chromite Crystallography
Help on Cell Dimensions: Cell Dimensions: a = 8.36, Z = 8; V = 584.28 Den(Calc)= 5.09
Help on Crystal System: Crystal System: Isometric - HexoctahedralH-M Symbol (4/m 3 2/m) Space Group: F d3m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.52(1), 1.46(0.9), 1.6(0.9),
Help on Forms: Forms:

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Forms: [ 1 1 1]

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Lenaz D , Princivalle F , The Canadian Mineralogist , 43 (2005) p.1305-1314, The crystal chemistry of detrital chromian spinel from the, southeastern Alps and Outer Dinarides: The discrimination of, supplies from areas of similar tectonic setting?, Sample: CL 1

View Additional jPOWD Structure files for Chromite
[1] [10] [2] [3] [4] [5] [6] [7] [8] [9]
 

Physical Properties of Chromite

Help on Cleavage: Cleavage: None
Help on Color: Color: Black, Brownish black.
Help on Density: Density: 4.5 - 5.09, Average = 4.79
Help on Diaphaniety: Diaphaniety: Opaque
Help on Fracture: Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Help on Habit: Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Habit: Habit: Nuggets - Irregular lumps produced by stream transport of malleable metals.
Help on Hardness: Hardness: 5.5 - Knife Blade
Help on Luminescence: Luminescence: None.
Help on Luster: Luster: Metallic
Help on Magnetism: Magnetism: Naturally weak
Help on Streak: Streak: brown
 

Optical Properties of Chromite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.092 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.145 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.22,KPDmeas= 0.2336,KC= 0.2573
Help on Optical Data: Optical Data: Isotropic, n=2.08-2.16.
Help on RL Color: RL Color: Gray-white with a brownish tint and brownish red internal reflections.
Help on RL Pleochroism: RL Pleochroism: None.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Chromite in Air
λ R  ∑ R(λ) 
 400 nm   13.20   
 420 nm   13.10 
 440 nm   13.00 
 460 nm   12.80 
 480 nm   12.60 
 500 nm   12.40 
 520 nm   12.20 
 540 nm   12.00 
 560 nm   11.90 
 580 nm   11.80 
 600 nm   11.70 
 620 nm   11.70 
 640 nm   11.60 
 660 nm   11.60 
 680 nm   11.60 
 700 nm   11.60 
Calculated Relative Intensity Colors of Chromite in Air
Relative
Intensity		    0%   80% 100% 160% 240% 320% 400% 480% 560% 640% 720% 740%
R                        
 

Calculated Properties of Chromite

Help on Electron Density: Electron Density:

relectron=4.54 gm/cc
note: rChromite =4.80 gm/cc.
Help on Fermion Index Fermion Index Fermion Index = 0.04956
Boson Index = 0.95044
Help on Photoelectric: Photoelectric:

PEChromite = 18.28 barns/electron
U=PEChromite x relectron= 83.03 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Chromite is Not Radioactive
 

Chromite Classification
Help on Dana Class: Dana Class: 7.2.3.3 (7)Multiple Oxides
  (7.2)(A+ B++)2 X4 Spinel group
  (7.2.3)(Chromium subgroup)
 
7.2.3.1 Magnesiochromite MgCr2O4 F d3m 4/m 3 2/m
 
7.2.3.2 Manganochromite (Mn,Fe)(Cr,V)2O4 F d3m 4/m 3 2/m
 
7.2.3.3 Chromite FeCr2O4 F d3m 4/m 3 2/m
 
7.2.3.4 Nichromite (Ni,Co,Fe)(Cr,Fe,Al)2O4 F d3m 4/m 3 2/m
 
7.2.3.5 Cochromite (Co,Ni,Fe)(Cr,Al)2O4 F d3m 4/m 3 2/m
 
7.2.3.6 Zincochromite ZnCr2O4 F d3m 4/m 3 2/m
Help on Strunz Class: Strunz Class: IV/B.03-20 IV - Oxides
  IV/B - Oxides with metal : oxygen = 3:4 (spinel type M3O4 and related) Chromite-Spinels
  IV/B.03 - Spinel group, Magnesio-chromite - Zinco-chromite series
 
IV/B.03-10 Magnesiochromite MgCr2O4 F d3m 4/m 3 2/m
 
IV/B.03-20 Chromite FeCr2O4 F d3m 4/m 3 2/m
 
IV/B.03-30 Manganochromite (Mn,Fe)(Cr,V)2O4 F d3m 4/m 3 2/m
 
IV/B.03-40 Cochromite (Co,Ni,Fe)(Cr,Al)2O4 F d3m 4/m 3 2/m
 
IV/B.03-50 Nichromite (Ni,Co,Fe)(Cr,Fe,Al)2O4 F d3m 4/m 3 2/m
 
IV/B.03-60 Zincochromite ZnCr2O4 F d3m 4/m 3 2/m
 

Other Chromite Information
Help on References: References: NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
Help on See Also: See Also: Links to other databases for Chromite :
1 -Am. Min. Crystal Structure Database 2 - Amethyst Galleries' Mineral Gallery 3 - Applied Mineralogy 4 - Applied Mineralogy 5 -Athena 6 - Crocoite.com Mineral Locations 7 - EUROmin Project 8 - Glendale Community College 9 -Google Images 10 -Google Scholar 11 - HyperPhysics 12 -MinDAT 13 -MinMax(Deutsch) 14 -MinMax(English) 15 - Mineral and Gemstone Kingdom 16 -Mineralienatlas (Deutsch) 17 - Minerals of Wisconsin 18 - Philatelic Mineralogy 19 -QUT Mineral Atlas 20 - Scandinavian mineral gallery 21 -University of Colorado - Mineral Structure Data 22 -University of Minnesota 23 - WWW-MINCRYST 24 -École des Mines de Paris

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Chromite

Fe++Cr2O4
Dana No: 7.2.3.3 Strunz No: IV/B.03-20
Locality:

 

Notes:

 
 
   
 
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