Sharp yellowish tan crystals of the extremely rare Fe-Al phosphate mineral mcauslanite from the type and only known locality worldwide in Nova Scotia (East Kemptville, Argyle, Yarmouth County, Nova Scotia, Canada). Ex Vandenbroucke Museum collection specimen, from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Mcauslanite
Mcauslanite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Fe²⁺₃Al₂(PO₄)₃(PO₃OH)F·18H₂O.
It crystallizes in the triclinic crystal system.
Key properties: Mohs hardness 3.5; specific gravity 2.22; White streak; Vitreous to silky luster; optically biaxial.
IMA symbol Mas, IMA status: approved, named in 1986.
A very rare non-oxidized secondary mineral along joints beneath the erosional surface of a greisen-hosted stockwork tin mine.
It is found associated with Vivianite, phosphophyllite, childrenite–eosphorite.
The mineral was named to honor Dr. David A. McAuslan (1943–), Exploration Manager for Shell Canada Resources Ltd., developers of the East Kemptville tin mine, Canada.