Outstanding acicular white crystals of the very rare phosphate mineral angastonite intermixed with the extremely rare elliottite (IMA 2021-113) from the type locality for both minerals in Penrice quarry, Angaston, Australia. Both minerals are visually indistinguishable. Ex. Erich Laskowski collection. — Photo: David Hospital · CC BY-SA 4.0
Elliottite
Elliottite is an IMA-recognized mineral species in the phosphate class, with the chemical formula NaMgAl₃(PO₄)₂F₆·9H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m).
Key properties: specific gravity 2.09; White streak; optically biaxial.
IMA symbol Eli, IMA status: approved, named in 2022.
Secondary in phosphate rock derived from weathered argillaceous rocks by alteration of minyulite in near-neutral solutions.
It is found associated with Minyulite, penriceite, wavellite, “angastonite”, goethite (Tom’s quarry); crandallite, minyulite, penriceite, perhamite, quartz.
The mineral was named to honor Peter Elliott (b.