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 occurs as granular masses and as slender prismatic crystals. It ahs 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. It is a minor ore of tungsten.It was discovered in 1863 in Sierra Almagrera, Spain. It was named after Moritz Rudolph Ferber (1805-1875).
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General Information:
 Chemical Formula:
Fe++WO4
 Composition:
(Molecular Weight = 303.69 gm)
Iron 18.39 % Fe
Tungsten 60.54 % W 
Oxygen 21.07 % O 
 Empirical Formula:
Fe2+(WO4)
 Name Origin:
After Rudolph Ferber of Gera, Germany.
Physical Properties:
 Cleavage:
[010] Perfect
 Color:
black.
 Density:
7.5 - 7.4, Average = 7.45
 Diaphaniety:
Opaque
 Habits:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Lamellar - Thin laminae producing a lamellar structure., Massive - Granular - Common texture observed in granite an d other igneous rock.
 Hardness:
4.5 - Between Fluorite and Apatite
 Luster:
Sub Metallic
 Streak:
brownish black
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