Chemical Formula: MnWO4
Locality: Erie and Enterprise veins, Ellsworth (Mammoth) district, Nye County, Nevada, USA.
Name Origin: After the German mineralogist, Adolph Huebner.
Hübnerite or hubnerite is a mineral consisting of manganese tungsten oxide (chemical formula: MnWO4, it isn’t a tungstate). It is the manganese endmember of the manganese – iron wolframite solid solution series. It forms reddish brown to black monoclinic prismatic submetallic crystals. The crystals are typically flattened and occur with fine striations. It has a high specific gravity of 7.15 and a Mohs hardness of 4.5. It is transparent to translucent with perfect cleavage. Refractive index values are nα=2.170 – 2.200, nβ=2.220, and nγ=2.300 – 2.320.
Typical occurrence is in association with high-temperature hydrothermal vein deposits and altered granites with greisen, granite pegmatites and in alluvial deposits. It occurs associated with cassiterite, arsenopyrite, molybdenite, tourmaline, topaz, rhodochrosite and fluorite.
It was first described in 1865 for an occurrence in the Erie and Enterprise veins, Mammoth district, Nye County, Nevada, and named after the German mining engineer and metallurgist, Adolf Huebner from Freiberg, Saxony
Physical Properties
Cleavage: {010} Perfect
Color: Brown, Reddish brown, Brownish black.
Density: 7.2 – 7.1, Average = 7.15
Diaphaneity: Transparent to Translucent
Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals.
Hardness: 4.5 – Between Fluorite and Apatite
Luster: Sub Metallic
Streak: reddish brown
Photos :
 district, Nye County, Nevada, USA. Name Origin: After the Germ){kind=link}