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
Streak	Black to brown
Specific gravity	7 - 7.5
Refractive index	Opaque
Pleochroism	None
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

• List of minerals

[edit] References

1. ^ Peter van der Krogt. "Wolframium Wolfram Tungsten". Elementymology & Elements Multidict. http://elements.vanderkrogt.net/elem/w.html. Retrieved 2008-05-14. 

• Webmineral data
• Mindat.org
• spiritone.com

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