Dittmarite

dittmarite

struvite

hannayite

schertelite

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Formula: (NH₄)Mg(PO₄).H₂O
Hydrated phosphate
Crystal System: Orthorhombic
Specific gravity: 2.15 measured, 2.19 calculated
Hardness: 5
Streak: White
Colour: Colourless
Environments

Cave deposits

Dittmarite is found in dryer parts of bat guano in caves (Webmin)

Localities

At the Wooltana Cave, Wooltana homestead area, North Flinders Ranges, Flinders Ranges, South Australia, the principal mineral is whitlockite with dittmarite, biphosphammite, görgeyite, brushite, gypsum and whewellite. Dittmarite is a very rare mineral and it cannot be formed directly in caves as it is normally crystallised from boiling water. It is proposed that it is formed by decomposition of struvite in the presence of ammonia arising from the fresh bat guano. The minerals dittmarite, struvite and newberyite, can transform between themselves in caves and in kidney stones (in vitro) according to the conditions. The cave walls are dolomite. (Transactions of the Royal Society of South Australia(2014), 138(2): 214–230).

At the type locality, the Skipton Caves, Mt. Widderin, Skipton, Corangamite Shire, Victoria, Australia, dittmarite is associated with struvite, newberyite, hannayite and schertelite (HOM, Dana).

At Arnhem Cave, Windhoek Rural, Khomas Region, Namibia dittmarite occurs with swaknoite, mundrabillaite and arcanite (HOM).

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