Austinite on calcite Field of view: 10 mm Locality: Christiana Mine, Agios Konstantinos (Kamariza), Lavrion mining district, Lavreotiki, East Attica, Attica, Greece ( locality at mindat.org ) — Photo: Henk Smeets – tomeikminerals.com · CC BY 4.0
Austinite
Austinite is an IMA-recognized mineral species in the arsenate class, with the chemical formula CaZn(AsO₄)(OH).
It crystallizes in the orthorhombic crystal system (space group P2_12_12_1). It is a member of the Adelite structural group.
Key properties: Mohs hardness 4–4.5; specific gravity 4.13; Subadamantine to silky in aggregates luster; refractive index 1.768; optically biaxial.
IMA symbol Aus, grandfathered status — known before the IMA’s founding, named in 1935.
A rare secondary mineral found in the oxidized zone of some arsenic-rich base-metal deposits.
It is found associated with Adamite, talmessite, “limonite”, quartz (Gold Hill, Utah, USA).
The mineral was named to honor Professor Austin Flint Rogers (1877–1957), American mineralogist, Stanford University, Palo Alto, California, USA.