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Formula: (NH4)2Mg(PO3OH)2.4H2O
Hydrated acid phosphate
Specific gravity: 1.83
Streak: White
Colour: Colourless
Solubility: Dissolves rapidly in water forming struvite (AM 48.635-641)
Environments
Schertelite is formed in drier portions of bat guano, by the reaction of NH4 from guano with Mg in
surrounding rocks (Webmin, HOM). Schertelite, hannayite,
bobierrite, newberyite and
struvite are reported to be commonly associated minerals
(AM 48.635-641).
Localities
At the type locality, the Skipton Caves, Mount Widderin, Skipton, Corangamite Shire, Victoria, Australia,
schertelite is associated with struvite and
newberyite
(HOM).
Alteration
Mixtures of the commonly associated minerals hannayite, schertelite,
bobierrite, newberyite and
struvite may be formed by reaction of magnesium with concentrated ammonium
phosphate solutions of the guano deposit, followed by alterations in the course of leaching and aeration. In laboratory
preparations, hannayite and schertelite precipitate rapidly from
concentrated solutions of ammonium phosphate over the pH range 3.5 to 6 (acid) and the temperature range 25 to
100oC. Newberyite or
struvite, depending on the pH, is formed at lower concentrations of ammonium
phosphate. When either newberyite or
struvite is placed in a saturated solution of monoammonium phosphate, it is
replaced by hannayite, which then alters to schertelite in a few days
(AM 48.635-641).
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