Exceptional sample of the extremely rare demicheleite-(Cl) (IMA 2008-020) in well formed red microcrystals and associated to white godovikovite. The mineral is found only in this locality worldwide and it has an unusual chemistry, as it is a bismuth sulphide chloride (BiSCl). From: La Fossa Crater, Vulcano Island, Messina Province, Sicily, Italy. — Photo: David Hospital · CC BY-SA 4.0
Demicheleite-(Cl)
Demicheleite-(Cl) is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula BiSCl.
It crystallizes in the orthorhombic crystal system (space group Pnam). It is a member of the Demicheleite structural group.
Key properties: specific gravity 5.934; Brown streak; Submetallic luster.
IMA symbol Dem-Cl, IMA status: approved, named in 2008.
A product of fumarolic alteration of pyroclastic breccia.
It is found associated with Demicheleite-(Br), bismoclite, bismuthinite, godovikovite, panichiite, aiolosite, brontesite, adranosite.
The mineral was named to honor Vincenzo de Michele (b. 1936), former curator of the Natural History Museum, Milan, Italy, and suffix for its chemical composition.