Kozyrevskite
Kozyrevskite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Cu₄O(AsO₄)₂.
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Kozyrevskite structural group.
Key properties: Mohs hardness 3.5; specific gravity 4.934; Very light green streak; Vitreous luster; optically biaxial.
IMA symbol Kzy, IMA status: approved, named in 2013.
Occurs as complex incrustations on the surface of basalt scoria or in open pockets. Deposited directly from volcanic gas or as the result of gas-rock interactions at temperatures > 380 flC.
It is found associated with Ericlaxmanite, urusovite, lammerite, lammerite-β, popovite, alarsite.
The mineral was named to honor the Russian geographer and traveler, Cossack officer Ivan Petrovich Kozyrevskiy (1680-1734).