Platy metallic crystals of the very rare sulphosal mineral wittite from the famous locality LaFossa Crater (La Fossa Crater, Vulcano Island, Aeolian Islands, Sicily, Italy) and associated to acicular metallic bismuthinite. Analyzed specimen. — Photo: David Hospital · CC BY-SA 4.0
Wittite
Wittite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Pb₈Bi₁₀(S,Se)₂₃.
It crystallizes in the monoclinic crystal system (space group C2/m).
Key properties: Mohs hardness 2–2.5; specific gravity 7.12; Black streak; Metallic. R1 –R2: (400) 43.2–45.3, (420) 42.8–44.9, (440) 42.4–44.5, (460) 41.9–44.2, (480) 41.5–43.8, (500) 41.1–43.3 luster.
IMA symbol Wit, IMA status: questionable, named in 1924.
Found in an amphibolite rock (Falun, Sweden); in garnet tactite (Middlemarch Canyon, Arizona, USA).
It is found associated with Nordströmite, friedrichite, magnetite, pyrite, cordierite, quartz (Falun, Sweden).
The name refers to T. Witt, Swedish mining engineer.