White massive specimen of the rare phosphate mineral peisleyite from the type and only known locality worldwide: Toms Phosphate Quarry, Kapunda, South Australia, Australia. — Photo: David Hospital · CC BY-SA 4.0
Peisleyite
Peisleyite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Na₃Al₁₆(PO₄)₁₀(SO₄)₂(OH)₁₇·20H₂O.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: Mohs hardness 3; specific gravity 2.2; Earthy luster.
IMA symbol Pei, IMA status: approved, named in 1981.
Found as a rare secondary mineral in phosphate beds in limestone.
It is found associated with F-rich wavellite.
The mineral was named to honor Mr. Vincent Peisley (b. 1941), Brahma Lodge, Australia, who first collected the species.