ferberite

Ferberite is an iron tungstate mineral with the chemical formula FeWO4. It is the iron endmember of the wolframite group, which forms a continuous solid solution with MnWO4 (hubnerite). Ferberite commonly occurs in hydrothermal tungsten veins and granitic pegmatites and is typically found together with other tungsten minerals such as scheelite, as well as quartz, cassiterite, and bismuth minerals.

In terms of crystallography and appearance, ferberite crystallizes in the monoclinic system. Crystals are typically prismatic to tabular and tend to be brown to black with a metallic to submetallic luster. The streak is brownish gray, and cleavage is indistinct. Ferberite has a Mohs hardness of about 4.5 to 5.5 and a specific gravity in the range of roughly 7.3 to 7.6, reflecting its high tungsten content.

Economically, ferberite is an important ore of tungsten. Concentrates of ferberite are processed to produce tungsten oxide, which is refined into tungsten metal used for hard alloys, tools, and various electronics applications. Because it forms with other tungsten-bearing minerals, ferberite commonly occurs in ore deposits alongside scheelite and other hydrothermal tungsten minerals.

Geographically, ferberite occurs in tungsten districts around the world, including historic deposits in classic tungsten provinces and ongoing production areas. The mineral is chosen for identification and ore characterization in tungsten mining and processing, where its iron content helps distinguish it from other members of the wolframite group.