Wolframite

Wolframite

General
Category	Tungstate
Formula (repeating unit)	(Fe,Mn)WO₄
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	P2/c
Unit cell	a = 4.77 Å, b = 5.73 Å c = 4.98 Å; β = 90.2°; Z = 2
Identification
Color	Grayish to brownish black
Crystal habit	Tabular to short prismatic crystals
Cleavage	Perfect 010
Fracture	Uneven to rough
Mohs scale hardness	4-4.5
Luster	Submetallic to resinous
Streak	Reddish brown
Diaphaneity	Opaque
Specific gravity	7 - 7.5
Pleochroism	None
Fusibility	3 - 4 to magnetic globule
Solubility	insoluble
References

Wolframite, (Fe,Mn)WO₄, is an iron manganese tungstate mineral that is the intermediate between ferberite (Fe²⁺ rich) and hübnerite (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.

This mineral was historically found in Europe in Bohemia, Saxony, and Cornwall. China reportedly has the world's largest supply of tungsten ore with about 60%. Other producers are Canada, Portugal, Russia, Australia, Thailand, South Korea, Rwanda, Bolivia, the United States, and the Democratic Republic of the Congo.

The name "wolframite" is derived from German "wolf rahm", the name given to tungsten by Johan Gottschalk Wallerius in 1747. This, in turn, derives from "Lupi spuma", the name Georg Agricola used for the element in 1546, which translates into English as "wolf's froth" or "cream". The etymology is not entirely certain but seems to be a reference to the large amounts of tin consumed by the mineral during its extraction. Wolfram is the basis for the chemical symbol W for tungsten as a chemical element.

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