Exceptional and very rich sample of the extremely rare mineral (IMA 2007-022) demicheleite-(Br) in well formed metallic deep red crystals. The mineral is found only in this locality worldwide ( La Fossa Crater, Vulcano Island, Messina Province, Sicily, Italy) and it has an unusual chemistry, as it is a bismuth sulphide bromide (BiSBr). Analyzed by SEM/EDS. — Photo: David Hospital · CC BY-SA 4.0
Demicheleite-(Br)
Demicheleite-(Br) is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula BiSBr.
It crystallizes in the orthorhombic crystal system (space group Pnam). It is a member of the Demicheleite structural group.
Key properties: specific gravity 6.312; Red streak; Submetallic luster.
IMA symbol Dem-Br, IMA status: approved, named in 2007.
A product of fumarolic alteration of pyroclastic breccia.
It is found associated with Demicheleite-(I), pseudocotunnite, bismoclite, bismuthinite, cotunnite, challacolloite.
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.