Fedotovite
Fedotovite is an IMA-recognized mineral species in the sulfate class, with the chemical formula K₂Cu₃O(SO₄)₃.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Euchlorine structural group.
Key properties: Mohs hardness 2.5; specific gravity 3.205; Pale grass-green streak; Vitreous to silky luster; optically biaxial.
IMA symbol Fdt, IMA status: approved, named in 1986.
Occurs as sublimates around volcanic fumaroles.
It is found associated with Dolerophanite, chalcocyanite, tolbachite, piypite, melanothallite, tenorite, vergasovaite, euchlorine, alarsite, klyuchevskite, lammerite, nabokoite.
The mineral was named to honor Sergei Aleksandrovich Fedotov (1931–), volcanologist and seismologist, Director of the Institute of Volcanology, Petropavlovsk-Kamchatkskii, Russia.