Colorless-pale beige crystal aggregates of the extremely rare ammonium phosphate mineral schertelite from the type locality in Australia (Skipton Caves, Mount Widderin, Corangamite Shire, Victoria, Australia), and only one of the two known localities worldwide. A phosphate mineral found in bat guano deposits. Ex Vandenbroucke Museum collection specimen, from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Schertelite
Schertelite is an IMA-recognized mineral species in the phosphate class, with the chemical formula (NH₄)₂Mg(PO₃OH)₂·4H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbca).
Key properties: specific gravity 1.83; optically biaxial.
IMA symbol She, grandfathered status — known before the IMA’s founding, named in 1902.
Rarely formed in drier portions of bat guano, by the reaction of NH4 from guano with Mg in surrounding rocks.
It is found associated with Struvite, newberyite (Skipton lava tube caves, Australia).
The mineral was named to honor Professor Arnulf Schertel (1841-1902), mineralogist, Freiberg Mining Academy, Freiberg, Germany.