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.
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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:
PEMagnesiochromite = 12.54 barns/electron U=PEMagnesiochromite x rElectron Density= 54.01 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Magnesiochromite is Not Radioactive
Chemical Formula: 
