White globular aggregates of the rare mineral aldermanite from the type locality (Moculta Phosphate Quarry, Angaston, South Australia, Australia) and of the very few known localities, all of them in South Australia. — Photo: David Hospital · CC BY-SA 4.0
Aldermanite
A rare hydrated magnesium-aluminium phosphate named for A. R. Alderman, professor of geology at the University of Adelaide.
Intro adapted from Wikipedia (CC BY-SA).
Aldermanite is an IMA-recognized mineral species in the phosphate class, with the chemical formula [Mg(H₂O)₆][Na(H₂O)₂Al₃(PO₄)₂(OH)₆]·H₂O.
It crystallizes in the orthorhombic crystal system. It is a member of the Aldermanite structural group.
Key properties: Mohs hardness 2; Pearly luster.
IMA symbol Adm, IMA status: approved, named in 1980.
Found as a secondary mineral in cavities in a brecciated metamorphosed sedimentary phosphate deposit, formed by the alteration of fluellite (Moculta quarry, Australia).
It is found associated with Fluellite.
The mineral was named to honor Arthur Richard Alderman (1901–1980), Professor of Geology and Mineralogy, University of Adelaide, Adelaide, Australia.