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Chromite

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Formula:
Fe2+Cr3+2O4
Colour:
Black
Lustre:
Resinous, Greasy, Metallic, Sub-Metallic, Dull
Hardness:
Specific Gravity:
4.5 - 4.8
Crystal System:
Isometric
Member of:
Name:
Chromite was named in 1845 by Wilhelm Haidinger in allusion to its composition. The species was originally named fer chromate alumine by Louis Nicolas Vauquelin in 1798. Vauquelin was the discoverer of the element chromium.
Polymorph of:
Isostructural with:
Spinel Group. It apparently forms a complete solid solution series with many other members of the group, eg. in the Chromite-Hercynite Series, Chromite-Spinel Series, Chromite-Magnetite Series and the Chromite-Magnesiochromite Series. It is the iron analogue of Zincochromite, Cochromite, Manganochromite and Magnesiochromite and the Cr analogue of Hercynite, Coulsonite and Magnetite

It usually contains Mg, ferric iron [Fe(III)], Al and often Ti. "Ferritchromit", i.e. Fe(III) substitutions for Al and Cr, usually in grain rims, may give high total Fe contents and a false chromite identification. Of course, the definition requires dominant Fe(II)>Mg and Cr>Fe(III). (e.g. photo ID: 514894).

"Chromite" is commonly used for any Cr-rich mineral of the spinel group, particularly for the chromite-magnesiochromite series, and much of the mineral referred to as "chromite" in geological and petrological papers and mining statistics is usually Magnesiochromite. The Fe-dominant species - Chromite itself - can be FOUND, although uncommonly, in many "chromite" deposits, chromitite (rock name), and other "chromite"-bearing occurrences connected with hyperbasic rocks. As a rule of thumb, a member of the chromite-magnesiochromite series is twice as likely to be a magnesiochromite instead of a chromite. "Chromites" associated with olivine or serpentines, which are Mg-rich rocks, frequently have Mg-rich associated minerals. True chromite is common as inclusions in Diamonds from kimberlites (South Africa and Yakutia). Members of the spinel group may be enriched Cr and V in marbles (Slyudyanka), massive sulphide ores (Outokumpu) and also in some types of meteorites. In any case, "chromite" always needs ANALYTICAL CONFIRMATION. Note: Chromite, that is near end-member, has a higher specific gravity than near end-member magnesiochromite.


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Classification of ChromiteHide

Approved, 'Grandfathered' (first described prior to 1959)
First Published:
1845
4.BB.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
B : Metal: Oxygen = 3:4 and similar
B : With only medium-sized cations
7.2.3.3

7 : MULTIPLE OXIDES
2 : AB2X4
7.14.12

7 : Oxides and Hydroxides
14 : Oxides of Cr

Pronounciation of ChromiteHide

Pronounciation:
PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of ChromiteHide

Resinous, Greasy, Metallic, Sub-Metallic, Dull
Transparency:
Translucent, Opaque
Colour:
Black
Streak:
Brown
Hardness:
5½ on Mohs scale
Hardness:
VHN100=1278 - 1456 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
Parting may develop along {111}
Fracture:
Irregular/Uneven, Hackly, Sub-Conchoidal
Comment:
Broken surfaces frequently have an angular granulated appearance.
Density:
4.5 - 4.8 g/cm3 (Measured)    5.12 g/cm3 (Calculated)

Optical Data of ChromiteHide

Type:
Isotropic
RI values:
n = 2.08 - 2.16
Birefringence:
0.0
Max Birefringence:
δ = 0.000 - Isotropic minerals have no birefringence
Surface Relief:
Very High
Type:
Isotropic
Colour in reflected light:
Grey-white with brownish tint.
Internal Reflections:
Brownish red
Pleochroism:
Non-pleochroic

Chemical Properties of ChromiteHide

Formula:
Fe2+Cr3+2O4
IMA Formula:
Fe2+Cr2O4
Idealised Formula:
FeCr2O4
Common Impurities:
Mg,Mn,Zn,Al,Ti

Crystallography of ChromiteHide

Crystal System:
Isometric
Class (H-M):
m3m (4/m 3 2/m) - Hexoctahedral
Space Group:
Fd3m
Setting:
Fd3m
Cell Parameters:
a = 8.344 Å
Unit Cell V:
580.93 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Octahedral crystals uncommon, modified by {001} at times. Rarely, crystals may show small dodecahedral faces, etc. Usually massive, fine granular to compact.
Twinning:
On {111}

Crystallographic forms of ChromiteHide

Crystal Atlas:
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Chromite no.1 - Goldschmidt (1913-1926)
Chromite no.2 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by www.smorf.nl.

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Edge Lines | Miller Indicies | Axes

Transparency
Opaque | Translucent | Transparent

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X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
4.84 (10)
2.96 (30)
2.53 (100)
2.09 (20)
1.61 (40)
1.48 (50)
1.09 (10)
0.855 (10)
Comments:
ICDD 34-140 (synthetic). See also GSAM 85:195 (1962) natural material.

Occurrences of ChromiteHide

Paragenetic Mode(s):

Type Occurrence of ChromiteHide

Synonyms of ChromiteHide

Other Language Names for ChromiteHide

Varieties of ChromiteHide

Aluminian ChromiteAn aluminian variety of Chromite. Cr:Al from 3:1 to 1:1
AlumoberezoviteA magnesian aluminian Chromite
BerezovskiteA Magnesian Chromite
Chromferrit
Ferrian ChromiteA member of Chromite-Magnetite Series - a ferrian variety of Chromite with Fe3+ contents 0,10-0,50 apfu.
FerrichromiteA member of Chromite-Magnetite Series - a ferrian variety of Chromite with Fe3+ contents 0,50-1 apfu.
Titaniferous ChromiteA titanium-bearing variety of chromite.

Relationship of Chromite to other SpeciesHide

Member of:
Other Members of this group:
Cochromite(Co,Ni,Fe)(Cr,Al)2O4
CoulsoniteFe2+V3+2O4
CuprospinelCu2+Fe3+2O4Iso.
Filipstadite(Sb0.5Fe0.5)Mn2O4Iso.
FrankliniteZn2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
GahniteZnAl2O4Iso. m3m (4/m 3 2/m) : Fd3m
GalaxiteMn2+Al2O4Iso. m3m (4/m 3 2/m) : Fd3m
HercyniteFe2+Al2O4Iso. m3m (4/m 3 2/m) : Fd3m
JacobsiteMn2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
MagnesiochromiteMgCr2O4Iso. m3m (4/m 3 2/m) : Fd3m
MagnesiocoulsoniteMgV2O4Iso.
MagnesioferriteMgFe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
MagnetiteFe2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
ManganochromiteMn2+Cr2O4
Nichromite(Ni,Co,Fe)(Cr,Fe,Al)2O4Iso. m3m (4/m 3 2/m) : Fd3m
Qandilite(Mg,Fe3+)2(Ti,Fe3+,Al)O4
SpinelMgAl2O4Iso. m3m (4/m 3 2/m) : Fd3m
TrevoriteNi2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
UlvöspinelFe2TiO4Iso.
VuorelaineniteMn2+V3+2O4
XieiteFe2+Cr2O4Orth. mmm (2/m 2/m 2/m)
ZincochromiteZnCr2O4Iso.
Forms a series with:

Common AssociatesHide

Associated Minerals Based on Photo Data:
Serpentine Subgroup32 photos of Chromite associated with Serpentine Subgroup on mindat.org.
Chromian Clinochlore25 photos of Chromite associated with Chromian Clinochlore on mindat.org.
Uvarovite21 photos of Chromite associated with Uvarovite on mindat.org.
Grossular12 photos of Chromite associated with Grossular on mindat.org.
Olivine12 photos of Chromite associated with Olivine on mindat.org.
Antigorite11 photos of Chromite associated with Antigorite on mindat.org.
Magnetite11 photos of Chromite associated with Magnetite on mindat.org.
Phlogopite7 photos of Chromite associated with Phlogopite on mindat.org.
Mariinskite7 photos of Chromite associated with Mariinskite on mindat.org.
Stichtite6 photos of Chromite associated with Stichtite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

4.BB.05Cochromite(Co,Ni,Fe)(Cr,Al)2O4
4.BB.05CoulsoniteFe2+V3+2O4
4.BB.05CuprospinelCu2+Fe3+2O4Iso.
4.BB.05Filipstadite(Sb0.5Fe0.5)Mn2O4Iso.
4.BB.05FrankliniteZn2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05GahniteZnAl2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05GalaxiteMn2+Al2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05HercyniteFe2+Al2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05JacobsiteMn2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05ManganochromiteMn2+Cr2O4
4.BB.05MagnesiocoulsoniteMgV2O4Iso.
4.BB.05MagnesiochromiteMgCr2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05MagnesioferriteMgFe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05MagnetiteFe2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05Nichromite(Ni,Co,Fe)(Cr,Fe,Al)2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05Qandilite(Mg,Fe3+)2(Ti,Fe3+,Al)O4
4.BB.05SpinelMgAl2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05TrevoriteNi2+Fe3+2O4Iso. m3m (4/m 3 2/m) : Fd3m
4.BB.05UlvöspinelFe2TiO4Iso.
4.BB.05VuorelaineniteMn2+V3+2O4
4.BB.05ZincochromiteZnCr2O4Iso.
4.BB.10HausmanniteMn2+Mn3+2O4Tet. 4/mmm (4/m 2/m 2/m) : I41/amd
4.BB.10HetaeroliteZnMn2O4Tet. 4/mmm (4/m 2/m 2/m) : I41/amd
4.BB.10HydrohetaeroliteZnMn2O4 · H2OTet. 4/mmm (4/m 2/m 2/m) : I41/amd
4.BB.10IwakiiteMn2+Fe3+2O4Tet. 4/mmm (4/m 2/m 2/m) : I41/amd
4.BB.15MaghemiteFe3+2O3Iso. 4 3 2 : P41 3 2
4.BB.15TitanomaghemiteFe3+(Fe3+,Ti4+,Fe2+,◻)2O4Iso. 4 3 2 : P43 3 2
4.BB.20Tegengrenite(Mg,Mn2+)2Sb5+0.5(Mn3+,Si,Ti)0.5O4Trig.
4.BB.25XieiteFe2+Cr2O4Orth. mmm (2/m 2/m 2/m)

Related Minerals - Dana Grouping (8th Ed.)Hide

7.2.3.1MagnesiochromiteMgCr2O4Iso. m3m (4/m 3 2/m) : Fd3m
7.2.3.2ManganochromiteMn2+Cr2O4
7.2.3.4Nichromite(Ni,Co,Fe)(Cr,Fe,Al)2O4Iso. m3m (4/m 3 2/m) : Fd3m
7.2.3.5Cochromite(Co,Ni,Fe)(Cr,Al)2O4
7.2.3.6ZincochromiteZnCr2O4Iso.

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

7.14.1EskolaiteCr2O3Trig.
7.14.2BracewelliteCrO(OH)Orth. mmm (2/m 2/m 2/m)
7.14.3GrimaldiiteCrO(OH)Trig.
7.14.4GuyanaiteCrO(OH)Orth.
7.14.5YimengiteK(Cr,Ti,Fe,Mg)12O19Hex.
7.14.6Mathiasite(K, Ba, Sr)(Zr, Fe)(Mg,Fe)2 (Ti,Cr,Fe)18O38Trig.
7.14.7McconnelliteCuCrO2Trig.
7.14.8RedledgeiteBa(Ti4+6Cr3+2)O16Tet.
7.14.9HawthorneiteBaMgTi3Cr4Fe2+2Fe3+2O19Hex. 6/mmm (6/m 2/m 2/m) : P63/mmc
7.14.10ZincochromiteZnCr2O4Iso.
7.14.11Wattersite(Hg+2)2Hg2+(CrO4)O2Mon. 2/m : B2/b
7.14.13MagnesiochromiteMgCr2O4Iso. m3m (4/m 3 2/m) : Fd3m

Fluorescence of ChromiteHide

Not fluorescent in UV

Other InformationHide

Notes:
Some are weakly magnetic due to zones of magnetite composition, etc.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
Major ore source for chromium.

Chromite in petrologyHide

An essential component of (items highlighted in red)
Common component of (items highlighted in red)
Accessory component of (items highlighted in red)

References for ChromiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Vauqueline (1800), Bull. soc. philom.: 55: 57.
Pemberton, H. (1891), Chromite: Chem. News: 63: 241.
Simpson (1920), Mineralogical Magazine: 19: 99 (as Beresofite).
Palache, Charles, Harry Berman & Clifford Frondel (1944), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 709-712.
Bliss, N.W. and MacLean, W.H. (1975) The paragenesis of zoned chromite from central Manitoba. Geochimica et Cosmochimica Acta: 39: 973-990.
Da Silva, E.G., Abras, A., and Sette Camara, A.O.R. (1976) Mössbauer effect study of cation distribution in natural chromites. Journal of Applied Physics: 12: 783-785.
Fatseas, G.A., Dormann, J.L., and Blanchard, H. (1976) Study of the Fe 3+ / Fe 2+ ratio in natural chromites (Fe x Mg 1-x)(Cr 1-y-x Fe y Al z)O4. Journal of Physics: 12: 787-792.
Da Silva, E.G., Abras, A., and Speziali, L. (1980) Mössbauer effect study of cation distribution in natural chromites of Brazilian and Philippine origin. Journal of Applied Physics: 12: 389-392.
Osborne, M.D., Fleet, M.E., and Bancroft, G.M. (1981) Fe 2+ - Fe 3+ ordering in chromite and Cr-bearing spinels. Contributions to Mineralogy and Petrology: 77: 251-255.
Mitra, S., PAl, T., and Pal, T. (1991) Petrogenic implication of the Mössbauer hyperfine parameters of Fe 3+-chromites from Sukinda (India) ultramafites. Mineralogical Magazine: 55(4): 535:542.
Chen, Y.L., Xu, B.F., Chen, J.G., and ge, Y.Y. (1992) Fe 2+ - Fe 3+ ordered distribution in chromite spinels. Physics and Chemistry of Minerals: 19(4): 255-259.
Leblanc, M. and Ceuleneer, G. (1992) Chromite crystallisation in multicelular magma flow: evidence from a chromitite dike in the Oman ophiolite. Lithos: 27: 231-257.
Canadian Mineralogist (1994): 32: 729-746.
Zhou, Mei-Fu, Robinson, P.T., and Bai, W.J. (1994) Formartion of podiform chromitites by melt/rock interaction in the upper mantle. Mineral. Deposita: 29: 98-101.
Zhou, Mei-Fu, Robinson, P.T., Malpas, J., and Li, Z. (1996) Podiform chromitites in the Luobusa ophiolite (southern Tibet): implications for melt-rock interaction and chromite segregation in the upper mantle. Journal of Petrology: 37: 3-21.
Figueiras, J. and Waerenborgh, J.C. (1997) Fully oxidized chromite in the Serra Alta (South Portugal) quartzites: chemical and structural characterization and geological implications. Mineralogical Magazine: 61: 627-638.
Zhou, Mei-Fu and Robnson, P.T. (1997) Origin and tectonic environment of podiform chromite deposits. Economic geology: 92: 259-262.
Zhou, Mei-Fu, Sun, Min, Keays, R.R., and Kerrich, R.W. (1998) Controls on platinum-group elemental distributions of podiform chromitites: a case study of high-Cr and high-Al chromitites from Chinese orogenic belts. Geochimica et Cosmochimica Acta: 62: 677-688.
Barnes, S.J. (2000) Chromite in komatiites. II. Modification during greenschist to mid-amphibolite facies metamorphism. Journal of Petrology: 41: 387-409.
Salviulo, G., Carbonin, S., and Della Giusta, A. (2000) Powder and single-crystal X-ray structural refinements on a natural chromite: dependence of site occupancies on experimental strategies. Materials Science Forum: 321-324: 46-52.
Papike, J.J., Karner, J.M., and Shearer, C.K. (2004) Comparative planetary mineralogy: V/(Cr+Al) systematics in chromite as an indicator of relative oxygen fugacity. American Mineralogist: 89: 1557-1560.
Mosier, D.L., Singer, D.A., Moring, B.C., and Galloway, J.P., (2012), Podiform chromite deposits—database and grade and tonnage models: U.S. Geological Survey Scientific Investigations Report 2012–5157, 45 p. and database.

Internet Links for ChromiteHide

Localities for ChromiteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListShow