Wolframite

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Wolframite

General
Category Mineral
Chemical formula (Fe,Mn)WO4
Identification
Color Black (ferberite) to brown (huebnerite)
Crystal habit Tabular crystals, sometimes prismatic
Crystal system Monoclinic 2/m
Cleavage Perfect 010
Fracture Uneven to rough
Mohs Scale hardness 4-4.5
Luster Submetallic to resinous
Refractive index Opaque
Pleochroism None
Streak Black to brown
Specific gravity 7 - 7.5
Fusibility 3 - 4 to magnetic globule
Solubility Insoluble

Wolframite (Fe,Mn)WO4, is an iron manganese tungstate mineral that is the intermediate between ferberite (Fe2+ rich) and huebernite (Mn2+ rich). Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is found in quartz veins and pegmatites associated with granitic intrusives. Associated minerals include cassiterite, scheelite, bismuth, quartz, pyrite, galena, sphalerite, and arsenopyrite.

It was historically found in Bohemia, Saxony, and Cornwall. China reportedly has the world's largest supply of tungsten ore with about 60%. Other producers are Portugal, Russia, Australia, Thailand, Korea, Bolivia, and the United States.

The name comes from German Wolfram for tungsten [1] and provides the chemical symbol, W, for tungsten.

Wolframite was highly valued as the main source of the metal tungsten, a strong and dense material with many military uses. In WWII wolframite mines were a strategic asset as the metal was used in munitions. German industrial tools mostly used tungsten carbide. Also, tungsten was used in specialized armor piercing ammunition. This importance has decreased with the increasing use of depleted uranium for many of these applications.

[edit] See also

[edit] References

  1. ^ Peter van der Krogt. Wolframium Wolfram Tungsten. Elementymology & Elements Multidict. Retrieved on 2008-05-14.
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