Wolframite

Wolframite
General
Category	Oxide minerals
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
Fusibility	3–4 to magnetic globule
References	[1][2][3]

Wolframite is an iron, manganese, and tungstate mineral with a chemical formula of (Fe,Mn)WO₄ that is the intermediate mineral between ferberite (Fe²⁺ rich) and hübnerite (Mn²⁺ rich).^[4] 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.^[5] Associated minerals include cassiterite, scheelite, bismuth, quartz, pyrite, galena, sphalerite, and arsenopyrite.

This mineral was historically found in Europe in Bohemia, Saxony, and in the UK in Devon and Cornwall. China reportedly has the world's largest supply of tungsten ore with about 60%.^[6] Other producers are Spain, Canada, Portugal, Russia, Australia, Thailand, South Korea, Rwanda, Bolivia, the United States, and the Democratic Republic of the Congo.^[7]