Rozenite is a hydrous iron , Fe2+SO4•4(H2O).
It occurs as a secondary mineral, formed under low humidity at less than 21 °C (70 °F) as an alteration of copper-free melanterite , which is a post mine alteration product of pyrite. It also occurs in lacustrine seams. Associated minerals include melanterite, epsomite , gypsum , pyrite, marcasite and limonite
It was first described in 1960 for an occurrence on Ornak Mountain, Western Tatra Mountains , Poland (1874–1936).