Mineralogy Database

Chromite Mineral Data

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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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  Theophrastite   Chromite

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 - Hexoctahedral H-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),
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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 Diaphaneity: Diaphaneity: 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: Non-fluorescent.
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
Ncalc = 2.16 - 2.31
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: Bulk Density (Electron Density)=4.54 gm/cc
note: Specific Gravity of Chromite =4.80 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.04
Boson Index = 0.96
Help on Photoelectric: Photoelectric: PEChromite = 18.28 barns/electron
U=PEChromite x rElectron Density= 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: 07.02.03.03 (07)Multiple Oxides
  (07.02)(A+ B++)2 X4 Spinel group
  (07.02.03)(Chromium subgroup)
 
07.02.03.01 Magnesiochromite MgCr2O4 F d3m 4/m 3 2/m
 
07.02.03.02 Manganochromite (Mn,Fe)(Cr,V)2O4 F d3m 4/m 3 2/m
 
07.02.03.03 Chromite FeCr2O4 F d3m 4/m 3 2/m
 
07.02.03.04 Nichromite (Ni,Co,Fe)(Cr,Fe,Al)2O4 F d3m 4/m 3 2/m
 
07.02.03.05 Cochromite (Co,Ni,Fe)(Cr,Al)2O4 F d3m 4/m 3 2/m
 
07.02.03.06 Zincochromite ZnCr2O4 F d3m 4/m 3 2/m
Help on  Strunz Class: Strunz Class: 04.BB.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.B - Metal:Oxygen = 3:4 and similar
  04.BB -With only medium-sized cations
 
04.BB.05 Cochromite (Co,Ni,Fe)(Cr,Al)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Filipstadite (Mn,Mg)4SbFeO8 pseudo ISO 2/m 2/m 2/m
 
04.BB.05 Magnetite FeFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Gahnite ZnAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Chromite FeCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Galaxite (Mn,Mg)(Al,Fe)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Cuprospinel (Cu,Mg)Fe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Donathite? (Fe,Mg)(Cr,Fe)2O4 P 4/nnm 4/m 2/m 2/m
 
04.BB.05 Brunogeierite (Ge,Fe)Fe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Coulsonite FeV2O4 F d3m 4/m 3 2/m
 
04.BB.05 Hercynite FeAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Franklinite (Zn,Mn,Fe)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Jacobsite (Mn,Fe,Mg)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesiochromite MgCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesioferrite MgFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesiocoulsonite MgV2O4 F d3m 4/m 3 2/m
 
04.BB.05 Manganochromite (Mn,Fe)(Cr,V)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Qandilite (Mg,Fe)2(Ti,Fe,Al)O4 F d3m 4/m 3 2/m
 
04.BB.05 Nichromite (Ni,Co,Fe)(Cr,Fe,Al)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Spinel MgAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Ulvospinel TiFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Zincochromite ZnCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Trevorite NiFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Vuorelainenite (Mn,Fe)(V,Cr)2O4 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 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Glendale Community College
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - HyperPhysics
12 - MinDAT
13 - Mineral and Gemstone Kingdom
14 - Mineralienatlas (Deutsch)
15 - Online Mineral Museum
16 - Philatelic Mineralogy
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - Scandinavian mineral gallery
20 - University of Colorado - Mineral Structure Data
21 - WWW-MINCRYST

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

Chromite

Fe++Cr2O4
Dana No: 07.02.03.03 Strunz No: 04.BB.05
Locality:

 

Notes:

 

 
   
 


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