Wolframite

Name:
Wolframite
Detailed information:

M Formula:	(Fe,Mn)WO4
Properties:
Black to brown color, submetallic to resinous luster, black to brown streak. Mohs hardness 5–5.5, d 7.0–7.5.
Occurrence:
Colorado, South Dakota, Nevada, Australia, Bolivia, Europe.
Use:
Chief ore of tungsten.