FERBERITE
Ferberite is an iron tungstate mineral, FeWO4.
It is the iron-rich end member of a chemical spectrum called wolframite,
(Fe,Mn)WO4. It has a metallic to submetallic luster, black
color and streak, moderate hardness (H = 4 to 4.5), perfect cleavage, parting,
and a high specific gravity. Ferberite crystals are often described as
wedge-shaped; crystal faces tend to be striated. Ferberite also occurs in
massive and granular forms.
Ferberite has been reported from some hydrothermal
veins, some pegmatitic granites & altered granites, and in some alluvial
deposits.
Ferberite from the Tazna Mine, Atocha-Quechisla Mining District, Potosí
Department, Bolivia (CSM # 54433, Colorado School of Mines Geology Museum,
Golden, Colorado, USA).