HÜBNERITE, Slaskov, Czech Republic (miniature)

Hübnerite, a mineral composed of manganese tungsten oxide (MnWO4), represents the manganese endmember of the manganese–iron wolframite solid solution series. This mineral typically manifests as reddish-brown to black monoclinic prismatic crystals with a submetallic luster, often exhibiting flattened forms and fine striations. With a specific gravity of 7.15 and a Mohs hardness of 4.5, it is characterized by its transparency to translucency and perfect cleavage.