Nabokoite
Nabokoite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Cu₇Te⁴⁺O₄(SO₄)₅·KCl.
It crystallizes in the tetragonal crystal system (space group P4/ncc).
Key properties: Mohs hardness 2–2.5; specific gravity 4.18; Yellow- brown streak; Vitreous luster; optically uniaxial.
IMA symbol Nab, IMA status: approved, named in 1985.
A rare sublimate formed in a volcanic fumarole.
It is found associated with Atlasovite, chalcocyanite, dolerophanite, chloroxiphite, euchlorine, piypite, atacamite, alarsite, fedotovite, lammerite, klyuchevskite, anglesite.
The mineral was named to honor Sof’ya Ivanovna Naboko (1909–), Institute of Volcanology, Petropavlovsk-Kamchatskii, Russia, Russian volcanologist who first collected the mineral.