Buff to tan colored almost brown biphosphammite crystals associated to white archerite from the type locality in Australia: Murra-el-elevyn Cave, Dundas Shire, Western Australia, Australia. — Photo: David Hospital · CC BY-SA 4.0
Archerite
Archerite (IMA symbol: Aht) 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. It occurs in guano containing caves as wall encrustations and stalactites.
Intro adapted from Wikipedia (CC BY-SA).
Archerite is an IMA-recognized mineral species in the phosphate class, with the chemical formula H₂K(PO₄).
It crystallizes in the tetragonal crystal system (space group I-42d). It is a member of the Biphosphammite structural group.
Key properties: specific gravity 2.23.
IMA symbol Aht, IMA status: approved, named in 1975.
Found as a component of ~talactites and crusts on the walls of caves containing bat guano deposits.
It is found associated with Biphosphammite, aphthitalite, halite, syngenite, stercorite, oxammite, weddellite, whitlockite, guanine, newberyite, calcite, mundrabillaite.