Hübnerite

tungstate

pegmatites

Formula: Mn2+(WO4) anhydrous tungstate, but according to Mindat this species is misclassified in Dana 8th edition. There are no WO4 tetrahedra in it, so it should be classified as a simple oxide.
Hübnerite forms a complete solid solution series with ferberite.
Specific gravity: 7.12 to 7.18
Hardness: 4 to 4½
Streak: Greenish-grey, yellow to reddish-brown
Colour: Yellow-brown, reddish-brown, blackish brown, black, red (rare)
Environments:

Pegmatites
Sedimentary environments
Metamorphic environments
Hydrothermal environments

Hübnerite occurs in high-temperature (hypothermal) hydrothermal veins and medium temperature metamorphic rocks. It also occurs in granite pegmatites and in alluvial and residual deposits.
Associated minerals include cassiterite, arsenopyrite, molybdenite, tourmaline, topaz, rhodochrosite and fluorite.

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