Auriacusite Field of view: 0.4 mm Locality: Maria Josefa Mine, Rodalquilar, Almería, Andalusia, Spain — Photo: Henk Smeets – tomeikminerals.com · CC BY 4.0
Auriacusite
Auriacusite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Fe³⁺Cu²⁺(AsO₄)O.
It crystallizes in the orthorhombic crystal system (space group Pnnm). It is a member of the Andalusite structural group.
Key properties: Mohs hardness 3; specific gravity 4.447; Brownish yellow streak; Silky luster; optically biaxial.
IMA symbol Aur, IMA status: approved, named in 2009.
Found as a secondary mineral in the weathering zone of a polymetallic sulfarsenide deposit.
It is found associated with Segnitite, brochantite, malachite, tetrahedrite, pyrite.
The name comes from the Latin auri (golden yellow) and acus (needle), in reference to its color and habit.