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 | |
| Category | Tungstate mineral |
| Formula (repeating unit) | FeWO4 |
| IMA symbol | Feb[1] |
| Strunz classification | 4.DB.30 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P2/c |
| Unit cell | a = 4.72, b = 5.7 c = 4.96 [Å]; β = 90°; Z = 2 |
| Identification | |
| Color | Black, dark brown in transmitted light |
| Crystal habit | Bladed crystals; massive |
| Twinning | Contact or interpenetrant or lamellar twins |
| Cleavage | Perfect on {010}; partings on {100} and {102} |
| Fracture | Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 4–4.5 |
| Luster | Submetallic to metallic adamantine |
| Streak | Brownish black |
| Diaphaneity | Nearly to entirely opaque |
| Specific gravity | 7.58 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 2.255 nβ = 2.305 nγ = 2.414 |
| Birefringence | δ = 0.159 |
| 2V angle | Measured: 66° |
| Other characteristics | Slightly 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]
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Twinned Ferberite, Tazna Mine, Atocha-Quechisla District, Nor Chichas Province, Potosí Department, Bolivia. 4.8 × 4.0 × 3.6 cm. -
Ferberite – Cínovec / Zinnwald, Erzgebirge; Krusné Hory Mts, Saxony and Ústí Region (Bohemia), Germany and Czech Republic
See also edit
References edit
- ^ 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.
- ^ a b Ferberite in the Handbook of Mineralogy
- ^ a b Ferberite on Mindat.org
- ^ Ferberite data on Webmineral site
- ^ Wolframite on Mindat
External links edit
