Wolframite

[Sarah]

Tungstate of iron and manganese, generally of a brownish orgrayish black color, submetallic luster, and high specific gravity.It occurs in cleavable masses, and also crystallized. Called alsowolfram.

[Kai]

a mineral consisting of iron and manganese tungstate in crystalline form; the principal ore of tungsten; found in quartz veins associated with granitic rocks