Hübnerite

Huebnerite is a mineral from the wolframite group, composed of manganese tungstate (MnWO₄). It occurs as prismatic or tabular crystals, ranging in color from reddish-brown to brownish-black, with a submetallic to resinous luster.

It forms in tungsten-rich hydrothermal veins, often associated with quartz, ferberite, and scheelite. Fine huebnerite crystals, particularly those from Peru, Bolivia, China, and the United States, are prized by collectors for their deep color, brilliance, and elegant crystalline morphology.