Erniggliite (Tl2SnAs2S6), a new mineral from Lengenbach, Binntal (Switzerland) : description and crystal structure determination based on data from synchrotron radiation

Erniggliite, Tl 2 SnAs 2 S 6 , is a new mineral species from the famous sulfosalt locality Lengenbach, Binntal (Switzerland). It occurs in small cavities in a dolomitic rock of Triassic age. Associated are a large number of various, mainly Tl-bearing As-sulfosalts such as hutchinsonite, hatchite, wallisite, lorandite, bernardite, abundant realgar and orpiment and two additional new minerals, edenharterite and stalderite. The mineral is characterized by its conspicuous hexagonal habit and an uncommon micaceous cleavage parallel to {0001}