Formula: Mg(PO3OH).3H2O
Hydrated acid phosphate
Specific gravity: 2.10 to 2.11
Hardness: 3 to 3½
Streak: White
Colour: Light Grey to white or colourless, pale brown; colourless in transmitted light.
Solubility: Very slightly soluble in cold water. Readily soluble in dilute hydrochloric acid

Cave deposits

Newberyite is found in caves, formed directly from bat guano (Webmin, HOM).


At the type locality, the Skipton Caves, Mount Widderin, Skipton, Corangamite Shire, Victoria, Australia, newberyite occurs in a bat guano cave deposit associated with hannayite and struvite (Mindat, Dana, HOM).

At the Petrogale Cave, Madura Roadhouse, Dundas Shire, Western Australia, newberyite is associated with biphosphammite (HOM ).

Near Dawson, Yukon, Canada, newberyite from the decaying tooth of a mammoth occurs with struvite and magnesite (Dana).

At Ascension Island, Saint Helena, in the South Atlantic, newberyite has been found in a specimen from the roof of a cavern in a young basalt flow (AM 13.397-401).

At Paoha Island, Mono Lake, Mono county, California, USA, newberyite occurs with monetite and struvite (HOM). The newberyite is a decomposition product of struvite which once formed as large crystals in or immediately below a guano deposit; the original struvite morphology has been preserved by a veneer of monetite (AM 51.1755-1765). Newberyite pseudomorphs after struvite have been found here (KL p197).


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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