ClassicGems.net

Hübnerite

Discovered in 1865;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

MnWO₄

Manganese Tungstate

Molecular Weight:

614.71 gm

Composition:

Manganese

18.14 %

Mn

23.43 %

MnO

Tungsten

60.72 %

W

76.57 %

WO₃

Oxygen

21.14 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/D.16-10

Nickel-Strunz 10th Ed. ID:

4.DB.30

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
B : With medium-sized cations; chains of edge-sharing octahedra

Related to:

Ferberite - Hübnerite Series

Synonyms:

Huebnerite

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals are prismatic; also lamellar, massive and granular.

Twinning:

Common as simple contact, as interpenetrant twins, lamellar,

Physical Properties

Cleavage:

[010] Perfect

Fracture:

Irregular to Uneven

Tenacity:

Brittle

Moh's Hardness:

4.0 - 4.5

Density:

7.12 - 7.20 (g/cm³) (very heavy)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Brown, Reddish Brown, Brownish Black, rarely Red

Transparency:

Transparent, Translucent, Opaque

Luster:

Adamantine, Resinous, Metallic

Refractive Index:

2.17 - 2.32  Biaxial ( + )

Birefringence:

0.1200 - 0.1300

Dispersion:

Relatively strong

Pleochroism:

Visible
X = yellow to green, orange-red;
Y = yellowish brown to greenish yellow, red-orange to red;
Z = green, brick red to red

Anisotrophism:

Strong; Color in reflected light: light gray; Internal reflections: white to brownish.
Distinctly Anisotropic; internal reflections: deep blood red

Occurances

Geological Setting:

In high temperature hydrothermal veins and pneumanolytically altered greisens; granite pegmatites and sedimentary alluvial deposits.

Type Locality:

Erie and Enterprize veins, Ellsworth mine, Ellsworth (Mammoth) District, Nye County, Nevada, USA

Year Discovered:

1865

View mineral photos:

Hübnerite Mineral Photos and Locations

Unusual Gem Categories

Anisotropic Gems, Black Gems

More Information

Mindat.org
Webmineral.com

Hübnerite is a rare member of the Wolframite mineral series that also includes Ferberite. Hübnerite is the Manganese (Mn) rich end member while Ferberite is the Iron (Fe) rich end member and Wolframite is the intermediate between the two. Hübnerite is a minor ore of Tungsten which is an important industrial element. Hübnerite is a very rare collector's gem. Gemstones are usually very dark reddish brown to black. It is a very interesting mineral in that it has very high refractive index and birefringence, strong dispersion, distinct pleochroism, extremely high density, adamantine to metallic luster and is distinctly anisotropic.

Hübnerite was discovered in 1865 at the Ellsworth mine, Nye County, Nevada, USA by German mining engineer Eugene N. Riotte. He named the new mineral Hübnerite to honor German mining engineer and metallurgist Friedrich Adolph Hübner (1830 - 1878?), from Freiberg, Saxony, Germany.

Hübnerite is found at many locations in the USA such as Arizona, California, Colorado, Idaho, Navada, New Mexico and South Dakota. Other worldwide locations include Australia, France, Czech Republic and Peru.

Hübnerite gems for sale: