Ajoite Field of view: 2 mm Locality: New Cornelia Mine, Pima County, Arizona, USA — Photo: Henk Smeets – tomeikminerals.com · CC BY 4.0
Ajoite
A hydrated copper-bearing silicate prized by collectors for its vivid blue-green color; minor manganese, iron and calcium often tag along.
Intro adapted from Wikipedia (CC BY-SA).
Ajoite is an IMA-recognized mineral species in the silicate class, with the chemical formula K₃Cu²⁺₂₀Al₃Si₂₉O₇₆(OH)₁₆·8H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Ajoite structural group.
Key properties: Mohs hardness 2; specific gravity 2.96; refractive index 1.591; optically biaxial.
IMA symbol Aj, IMA status: approved, named in 1958.
Found in oxidized copper-rich base-metal deposits.
It is found associated with Shattuckite, conichalcite, quartz, muscovite, pyrite (Ajo, Arizona, USA); creaseyite, fluorite (Potter-Cramer property, Arizona, USA); shattuckite, duhamelite.
The name refers to the type occurrence at Ajo, Arizona, USA.