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
Fluorapatite on ferberite from Minas da Panasqueira, Beira Baixa, Portugal
General
CategoryTungstate mineral
Formula
(repeating unit)		FeWO4
Strunz classification4.DB.30
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP2/c
Unit cella = 4.72, b = 5.7
c = 4.96 [Å]; β = 90°; Z = 2
Identification
ColorBlack, dark brown in transmitted light
Crystal habitBladed crystals; massive
TwinningContact or interpenetrant or lamellar twins
CleavagePerfect on {010}; partings on {100} and {102}
FractureUneven
TenacityBrittle
Mohs scale hardness4–4.5
LusterSubmetallic to metallic adamantine
StreakBrownish black
DiaphaneityNearly to entirely opaque
Specific gravity7.58
Optical propertiesBiaxial (+)
Refractive indexnα = 2.255 nβ = 2.305 nγ = 2.414
Birefringenceδ = 0.159
2V angleMeasured: 66°
Other characteristicsSlightly magnetic
References[1][2][3]

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.[4]

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.[1] 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).[2]

  • Twinned Ferberite, Tazna Mine, Atocha-Quechisla District, Nor Chichas Province, Potosí Department, Bolivia. 4.8 x 4.0 x 3.6 cm.
  • Ferberite - Cínovec / Zinnwald, Erzgebirge; Krusné Hory Mts, Saxony & Ústí Region (Bohemia), Germany & Czech Republic

See also

References
  1. Ferberite in the Handbook of Mineralogy
  2. Ferberite on Mindat.org
  3. Ferberite data on Webmineral site
  4. Wolframite on Mindat


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