Archerite is a phosphate mineral with chemical formula (K,NH₄)H₂PO₄. It's named after Michael Archer (born 25 March 1945), professor of Biology, University of New South Wales. Its type locality is Petrogale Cave, Madura Roadhouse, Dundas Shire, Western Australia, Australia. It occurs in guano containing caves as wall encrustations and stalactites.