Shuvalovite
Shuvalovite is an IMA-recognized mineral species in the sulfate class, with the chemical formula K₂(Ca₂Na)(SO₄)₃F.
It crystallizes in the orthorhombic crystal system (space group Pnma).
Key properties: Mohs hardness 3; specific gravity 2.641; White streak; Vitreous luster; optically biaxial.
IMA symbol Svv, IMA status: approved, named in 2014.
Occurs as crusts on scoria around a volcanic fumarole, probably through gas-rock interaction with basalt as a source of metals.
It is found associated with Tenorite, hematite, orthoclase, fluorophlogopite, langbeinite, aphthitalite, anhydrite, lammerite, johillerite, tilasite.
The mineral was named to honor Russian statesman Ivan Ivanovich Shuvalov (1727-1797), an enthusiastic patron of the sciences, arts and literature, and one of the founders of Moscow University in 1755.