Russoite, arsenite ammonium hydrate chloride (IMA 2015-105) found in the "Fumarola Bocca Grande" Phlegrean Fields, "Solfatara di Pozzuoli", (Campostrini et al. 2016).
Named after Massimo Russo born 1960, geologist and researcher at the "Osservatorio Vesuviano " National Institute of Geophysics and Volcanology in Naples.
Structurally the russoite is closely related to the lucabindiite.
Russoite is exclusive of its type locality in which is very rarely found as tabular hexagonal, colorless crystals.