Arnhemite and pyrophosphite are the principal phases in a slag that forms a thin layer in a profile of cave soil. The slag is interpreted to have resulted from the melting of ashes during the combustion of bat quano.
Not Approved IMA
Arhem Cave, 150 km east of Windhoek, Namibia. Link to MinDat.org Location Data.
Named after the Greek pyros, meaning fire and the element name - Phosphorus.