Metallic black crystal of the tungsten mineral tungstenite from the most famous locality for the mineral: Crevoladossola Quarry, Ossola Valley, Crevoladossola, Novara, Ossola Valley, Piedmont, Italy. Good contrast with the matrix. — Photo: David Hospital · CC BY-SA 4.0
Tungstenite
The rare mineral form of tungsten disulfide — a soft dark-gray mineral resembling molybdenite.
Intro adapted from Wikipedia (CC BY-SA).
Tungstenite is an IMA-recognized mineral species in the sulfide class, with the chemical formula WS₂.
It crystallizes in the hexagonal crystal system (space group P6_3/mmc). It is a member of the Molybdenite structural group.
Key properties: Mohs hardness 2.5; specific gravity 7.4; Metallic luster.
IMA symbol Tgt, grandfathered status — known before the IMA’s founding, named in 1917.
Found in a deposit replacing limestone (Emma mine, Utah, USA); replacing scheelite (Angokitsk deposit, Russia); in high-temperature fumaroles (Kudryavyy volcano, Russia).
It is found associated with Pyrite, sphalerite, galena, cinnabar, tetrahedrite, wolframite, scheelite, quartz.
The name refers to its composition.