Formula: (NH4)Mg(PO4).6H2O
Hydrated normal phosphate, struvite group
Specific gravity: 1.711
Hardness: 1½ to 2
Streak: White
Colour: Colourless, white (dehydrated), yellow or brownish, light grey; colourless in transmitted light
Solubility: Readily soluble in acids, very slightly soluble in water


Cave deposits

Struvite is typically formed in bird or bat guano in caves and surface deposits, associated with newberyite, hannayite, brushite and stercorite (HOM). It is found as a product of organic decay in putrescent matter, canned foods or other organic matter (Mindat, Webmin).


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

At the type locality, St Nikolai church, Hamburg, Germany, struvite was found in Medieval sewers (Mindat) in a bed of peat underlying deposits of organic matter (Dana).

At Paoha Island, Mono Lake, Mono county, California, USA, newberyite pseudomorphs after struvite have been found (KL p197).

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