what are the special features of chromite?!?

Answer 1

* Color is brownish black to a deep dark black.
* Luster is metallic to greasy.
* Transparency: Crystals are opaque.
* Crystal System is isometric; 4/m bar 3 2/m
* Crystal Habits include octahedrons often with dodecahedral faces modifing the edges of the octahedron to the point of rounding the crystal. Well formed crystals are rare and chromite is usually found massive or granular.
* Cleavage is absent.
* Fracture is conchoidal.
* Hardness is 5.5
* Specific Gravity is 4.5 - 4.8 (average for metallic minerals)
* Streak is brown.
* Other characteristics: Weakly magnetic and an octahedral parting is sometimes seen.
* Associated Minerals include olivine, talc, serpentine, uvarovite, pyroxenes, biotite, magnetite and anorthite.
* Notable Occurrences include several mines in North Carolina, Montana, Maryland, Oregon, Texas, California and Wyoming, USA also found in Turkey; South Africa; Philippines and Russia.
* Best Field Indicators are crystal habit, streak, associations with ultra-basic minerals and parting.

Hope that helps. =)

Answer 2

in: http://webmineral.com/data/Chromite.shtml

You'll find a lot of data - include the crystal shape (annimation).

Chemical Formula: Fe++Cr2O4
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

Environment: Cummulate mineral found in ultramafic portions of layered mafic intrusions. Common in meteorites.

IMA Status: Valid Species (Pre-IMA) 1845

Locality: Bastide de la Carrade, Gassin, Var, France. Link to MinDat.org Location Data.

Name Origin: Named after its chemical composition.

Synonym: Chrome iron ore
Chromic iron
Ferrichromite-magnetic, altered

Answer 3

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