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
Ferberite with muscovite from Minas da Panasqueira, Beira Baixa, Portugal
General
CategoryTungstate mineral
Formula
(repeating unit)
FeWO4
IMA symbolFeb[1]
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[2][3][4]

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.[5]

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.[2] 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).[3]

See also

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References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b Ferberite in the Handbook of Mineralogy
  3. ^ a b Ferberite on Mindat.org
  4. ^ Ferberite data on Webmineral site
  5. ^ Wolframite on Mindat
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