:Locality: Blyava Cu Deposit, Orensburgskaya Oblast, Urals Region, Russian Federation Size: 0.2 × 0.1 × 0.1 cm Description: Some aggregates of green avdoninite crystals from the Type Locality. In a glass capsule to avoid getting dehydrated. This species is a very rare fumarole potassium and copper chloride. — Photo: Joan Rosell , from rosellminerals.com · CC BY-SA 4.0
Avdoninite
Avdoninite is an IMA-recognized mineral species in the halide class, with the chemical formula K₂Cu₅Cl₈(OH)₄·2H₂O.
It crystallizes in the monoclinic crystal system.
Key properties: Mohs hardness 3; specific gravity 3.03; Pale green streak; Vitreous luster.
IMA symbol Avn, IMA status: approved, named in 2005.
A product of precipitation from fumarolic gases (Tolbachik Volcano, Russiaa); also reported as an alteration on massive sulfide ore exposed at the Earth’s surface.
It is found associated with Euchlorite, paratacamite, belloite, langbeinite, atacamite.
The mineral was named to honor Ural mineralogist Vladimir Nikolaevich Avdonin (1925–), senior scientist of the Ural Geological Museum, Ural State Mining University, Russia.