Kremersite
Kremersite is a rare mineral which is a hydrated multiple chloride of iron, ammonium and potassium with the formula: 2FeCl5·H2O. Kremersite is a brown-red to orange mineral that crystallizes in the orthorhombic system. It is a water-soluble mineral that is found around volcanic fumaroles. Occurs at Vesuvius, Italy and Mt. Etna, Sicily. It was discovered in 1853 and named for the German chemist, Peter Kremers.
