Tan crystsls of the very rare ammonium phosphate mineral phosphammite from one of the only two known localities worldwide. From Guañape Islands, Virù Province, Libertad Department, Peru. Phosphammite is one of the few ammonium minerals known. Ex Vandenbroucke Museum collection specimen, from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Phosphammite
Phosphammite is an IMA-recognized mineral species in the phosphate class, with the chemical formula (NH₄)₂(PO₃OH).
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: specific gravity 1.61; optically biaxial.
IMA symbol Pam, grandfathered status — known before the IMA’s founding, named in 1852.
Probably a crystallization product of the liquid fraction of guano.
It is found associated with Ammonian aphthitalite, urea, weddellite (Toppin Hill Cave, Western Australia); biphosphammite (Guañape Island, Peru).
As a PHOSPHate of AMMonium.