article


- align=center bgcolor="#9966FF"
Chromite
- align=center

- align=center bgcolor="#9966FF"
General
-
CategoryMineral
-
Chemical formulairon magnesium chromium oxide:(Fe,Mg)Cr2O4
- align="center" bgcolor="#9966FF"
Identification
-
Color Black to brownish black
-
Crystal habit Octahedral rare; massive to granular
-
Crystal system Isometric; hexoctahedral
-
Cleavageabsent
-
FractureConchoidal
-
Mohs Scale hardness 5.5
-
LusterSubmetallic
-
Refractive indexSubtranslucent to opaque
-
Pleochroism N/A
-
Streak Dark brown
-
Specific gravity 4.5 - 4.8
-
FusibilityInfusable
-
Solubility?
-
Other CharacteristicsWeakly magnetic
- align="center" bgcolor="#9966FF"
Major varieties
-
Magnesiochromite
-
Chromite, iron magnesium chromium oxide: (Fe,Mg)Cr2O4, is an oxide mineral belonging to the spinel group. Magnesium is always present in variable amounts, also aluminium and iron substitute for chromium.

Chromite is found in peridotite and other layered ultramafic intrusive rocks and also found in metamorphic rocks such as serpentinites. Ore deposits of chromite form as early magmatic differentiates. It is commonly associated with olivine, magnetite, serpentine, and corundum. The vast Bushveld igneous complex of South Africa is a large layered mafic to ultramafic igneous body with some layers consisting of 90% chromite making the rare rock type, chromitite. Chromite is the chief ore of chromium.

Chromite is also used as a refractory material.

Chromite is found in Afghanistan, Iran, Pakistan, Oman, Zimbabwe.

In Pakistan Chromite has been mined in the Zhob District of Baluchistan since 1902. Currently the major mining company in Pakistan is Pakistan Chrome Mines Ltd. Chromite is found in the ultramfic rocks in the Zhob District of Baluchistan, Most of the Chromite is of metalurgical grade with Cr2O3 averaging 46% and a chrome to iron ration of 3:1.

References and external links


http://minerals.usgs.gov/minerals/pubs/country/1998/9324098.pdf

Magnesium minerals | Iron minerals | Chromium minerals | Oxide minerals | Refractory materials

Chromeisenstein | Cromita | Cromite | Chromiet | クロム鉄鉱 | Cromita | Kromiitti

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Chromite".

Home Pageartsbusinesscomputersgameshealthhospitalshomekids & teensnewsphysiciansrecreationreferenceregionalscienceshoppingsocietysportsworld