Wiktionary
ferrimolybdite
n. (context mineral English) An orthorhombic mineral containing hydrogen, iron, molybdenum, and oxygen.
Wikipedia
Ferrimolybdite
Ferrimolybdite is a hydrous iron molybdate mineral with formula: Fe(MoO)·8(HO) or Fe(MoO)·n(HO). It forms coatings and radial aggregates of soft yellow needles which crystallize in the orthorhombic system.