Ferberite
Ferberite is the iron endmember of the manganese–iron wolframite solid solution series. The manganese endmember is hübnerite. Ferberite is a black monoclinic mineral composed of iron(II) tungstate, FeWO4.
Ferberite and hübnerite often contain both divalent cations of iron and manganese, with wolframite as the intermediate species for which the solid solution series is named.<ref>Wolframite on Mindat</ref>
Ferberite occurs as granular masses and as slender prismatic crystals. It has a Mohs hardness of 4.5 and a specific gravity of 7.4 to 7.5. Ferberite typically occurs in pegmatites, granitic greisens, and high temperature hydrothermal deposits.<ref name=HBM/> It is a minor ore of tungsten.
Ferberite was discovered in 1863 in Sierra Almagrera, Spain, and named after the German mineralogist Moritz Rudolph Ferber (1805–1875).<ref name=Mindat/>
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Twinned Ferberite, Tazna Mine, Atocha-Quechisla District, Nor Chichas Province, Potosí Department, Bolivia. 4.8 × 4.0 × 3.6 cm.
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Ferberite – Cínovec / Zinnwald, Erzgebirge; Krusné Hory Mts, Saxony and Ústí Region (Bohemia), Germany and Czech Republic