Chromite

Chromite

General
Category	Mineral
oxide: (Fe, Mg)Cr₂O₄
Identification
Color	Black to brownish black
Crystal habit	Octahedral rare; massive to granular
Isometric; hexoctahedral
Cleavage	absent
Fracture	Conchoidal
Mohs Scale hardness	5.5
Luster	Submetallic
Refractive index	Subtranslucent to opaque
Streak	Dark brown
Specific gravity	4.5 - 4.8
Fusibility	Infusible
Other Characteristics	Weakly magnetic
Major varieties
Magnesiochromite

Chromite, iron magnesium chromium oxide: (Fe, Mg)Cr₂O₄, is an iron substitute for chromium.

Chromite is found in ultramafic igneous body with some layers consisting of 90% chromite making the rare rock type, chromitite.

Chromite is also used as a refractory material.

The only ore of chromium is the mineral chromite. In the western hemisphere, chromite ore is produced only in Brazil and Cuba; By comparison, about 80% of world production of chromite comes from India, Iran, Pakistan, Oman, Zimbabwe, Turkey and Southern Africa. Southern Africa itself produces about half of this.

Chromite is mined from the ultramafic rocks in the Zhob District of Balochistan. Most of the chromite is of metallurgical grade with Cr₂O₃ averaging 46% and a chrome to iron ratio of 3:1.

References

Dana's Manual of Mineralogy ISBN 0-471-03288-3
Guilbert, John M., and Park, Charles F., Jr. (1986) The Geology of Ore Deposits, Freeman, ISBN 0-7167-1456-6
Mineral Galleries: Chromite
Webmineral.com
Minerals.net
USGS info.

Categories: Refractory materials

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Chromite". A list of authors is available in Wikipedia.