Magnesiochromite Mineral Data

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General Magnesiochromite Information

Chemical Formula:

MgCr2O4

Composition:

Molecular Weight = 192.29 gm

Magnesium 12.64 % Mg 20.96 % MgO

Chromium 54.08 % Cr 79.04 % Cr₂O₃

Oxygen 33.28 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

MgCr₂O₄

Environment:

Accessory mineral in ultramafic rocks, as dunites, serpentinites, kimberlites, lamproites, and komatiites. Forms two series, with chromite, and with spinel.

IMA Status:

Valid Species (Pre-IMA) 1868

Locality:

Kalarangi mines, Orissa, India. Link to MinDat.org Location Data.

Name Origin:

Named for a MAGNESIum-rich chromite.

Name Pronunciation:

Magnesiochromite

Synonym:

Chrompicotite

ICSD 20819

PDF 10-351

Magnesiochromite Image

Images:

Magnesiochromite

Comments: Black crystalline magnesiochromite grains in serpentinite.
Location: Red Pit, Fulton Township, Lancaster County, Pennsylvania, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Magnesiochromite Crystallography

Cell Dimensions:

a = 8.277, Z = 8; V = 567.05 Den(Calc)= 4.50

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/I_o): 2.49(1), 1.466(0.7), 1.593(0.6),

Forms:

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Forms: ( 1 1 1)

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Crystal Structure:

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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: BG 17B

View Additional jPOWD Structure files for Magnesiochromite
[1] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [2] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [3] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [4] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [5] [50] [51] [52] [53] [54] [55] [56] [57] [58] [6] [7] [8] [9]

Physical Properties of Magnesiochromite

Cleavage:

None

Color:

Black.

Density:

4.2

Diaphaneity:

Opaque

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Hardness:

5.5 - Knife Blade

Luster:

Metallic

Streak:

dark gray

Optical Properties of Magnesiochromite

Optical Data:

NCalc= 2.22 - from Gladstone-Dale relationship (KC = 0.2711) where Ncalc=Dcalc*KC+1
NCalc= 2.14 - from Gladstone-Dale relationship (KC = 0.2711) where Ncalc=Dmeas*KC+1

Calculated Properties of Magnesiochromite

Electron Density:

Bulk Density (Electron Density)=4.31 gm/cc
note: Specific Gravity of Magnesiochromite =4.50 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_{Magnesiochromite}= 12.54 barns/electron
U=PE_{Magnesiochromite} x rElectron Density= 54.01 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Magnesiochromite is Not Radioactive

Magnesiochromite Classification

Dana Class:

07.02.03.01 (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

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 Magnesiochromite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Magnesiochromite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (MinSocAm)
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - MinMax(Deutsch)
11 - MinMax(English)
12 - Mineral and Gemstone Kingdom
13 - Mineralienatlas (Deutsch)
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - University of Colorado - Mineral Structure Data
17 - WWW-MINCRYST

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

Magnesiochromite

MgCr2O4
Dana No: 07.02.03.01 Strunz No: 04.BB.05
Locality:

Notes: