Hubnerite
Hübnerite belongs to the tungstate group. It contains manganese and tungsten. Its chemical formula is MnWO₄.
Hübnerite typically presents tabular or flattened crystals of a very dark color, almost black, but dark red when viewed through the lens.
The density of Hübnerite is less than 7.3 (1 for water) and its hardness is less than 5 (10 for diamond). The streak on the porcelain is brownish-yellow.
The name Hübnerite comes from the name of the mining engineer A. Hübner.
