Spiridonovite
Spiridonovite is an IMA-recognized mineral species in the sulfide class, with the chemical formula (Cu₁₋ₓAgₓ)₂Te, (x≈0.4).
It crystallizes in the hexagonal crystal system (space group P-3c1). It is a member of the Fluorite structural group.
Key properties: Mohs hardness 3; specific gravity 4.6; Black streak; Metallic luster.
IMA symbol Srv, IMA status: approved, named in 2019.
Secondary after precious metals and tellurides localized in quartz veins.
It is found associated with Rickardite, vulcanite, cameronite, native tellurium. Distribution From the Good Hope mine, Vulcan, Gunnison Co., Colorado, USA.
The mineral was named to honor Professor Ernst M. Spiridonov (b. 1938), Department of Mineralogy, Moscow State University, Russia, who studied gold deposits of the Urals, Transbaikalia, Kamchatka.