Wiktionary
archerite
n. (context mineral English) A phosphate mineral found in guano caves.
Wikipedia
Archerite
Archerite is a phosphate mineral with chemical formula (K,NH)HPO. 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. It occurs in guano containing caves as wall encrustations and stalactites.