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Formula: (NH4)H2(PO4)
Anhydrous acid phosphate
Crystal System: Tetragonal
Specific gravity: 2.04 measured, 1.99 calculated
Hardness: 1 to 2
Streak: White
Colour: White, pale yellow or colourless, colourless in transmitted light
Environments
Biphosphammite occurs as an alteration of phosphammite in guano,
due to loss of ammonium (NH4) (Webmin).
Associated minerals include ammonium-aphthitalite,
phosphammite,
urea and weddellite
(Mindat).
Localities
At the type locality, Murra-el-elevyn Cave, Cocklebiddy Roadhouse, Dundas Shire, Western Australia, biphosphammite
occurs in crusts on bat guano as a byproduct of the reaction between the liquid fraction of bat guano and
urea. It is associated with syngenite
(HOM, Dana).
At the Guañape Islands, Virù Province, La Libertad, Peru, biphosphammite occurs as an alteration product of
phosphammite in guano, due to loss of ammonium (NH4).
Phosphammite remains as an associated mineral
(HOM ).
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