Hübnerite

Color differences between members of the wolframite family are clear and marked. The color of hübnerite varies from yellowish brown to reddish brown. Crystal and crystalline masses of hübnerite show a variety of lusters from adamantine, submetallic to resinous luster. In thin splints, hübnerite can be either transparent or translucent. The streak is related to the color being a shade lighter. All the wolframite minerals exhibit perfect cleavage on {010}. On {100} and {102}, parting is less well-developed. Hübnerite exhibits brittle and uneven fracture. It is common for all members of the wolframite family to show simple contact twins on {100} or rarely interpenetrant twins on {001}. The hardness of hübnerite is between 4 and 4.5 and its specific gravity is between 7.12 and 7.18.

Hübnerite is a rare member of the wolframite group. Hübnerite is usually found within pegmatites and high-temperature quartz veins. Hübnerite does not occur on its own, but is typically associated with other minerals such as cassiterite, scheelite, quartz, galena, arsenopyrite, native bismuth, pyrite, and sphalerite.

Since hübnerite comes from a family with only two end members it would be easier to explain the composition of the wolframite family since there is not enough data on hübnerite itself. The primary formula of the wolframite series is (Fe,Mn)WO4. The predominance of either iron or manganese results in formation of one of two minerals, the compositional end-members FeWO4 (ferberite) and MnWO4 (hübnerite), respectively.. Hübnerite is rarer than ferberite because of the difficulty of substituting manganese for iron. There are also other analogues, such as MgWO4. These compounds are usually referred to as "wolframites" because they share the wolframite structure, but are not naturally occurring minerals, typically being produced for industrial applications, e.g., crystal scintillators.

Hübnerite is a rare mineral, but is still a major ore of tungsten. Once processed, the tungsten can then be used to manufacture metal tools. Because it only occurs rarely, this mineral is a highly desired specimen among collectors.

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 Hübner from Freiberg, Saxony.