Phoxite
Phoxite is an IMA-recognized mineral species in the organic mineral class, with the chemical formula (NH₄)₂Mg₂(C₂O₄)(PO₃OH)₂(H₂O)₄.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Not in a structural group, Oxalate structural group.
Key properties: Mohs hardness 2.5; specific gravity 1.98; White streak; Vitreous to oily luster; optically biaxial.
IMA symbol Phx, IMA status: approved, named in 2018.
Found in a hot and humid area of an abandoned Cu-Pb-Au-Ag-Mo-V-barite-fluorspar mine in an unusual bat-guano-related, post-mining assemblage in portions of the interiors and rims of circular masses.
It is found associated with Antipinite, aphithitalite, bassanite, struvite, thenardite, weddellite.
Reflects the fact that the mineral contains essential phosphate (ph) and oxalate (ox) groups.