Itelmenite
A rare sodium-magnesium-copper sulfate from the fumaroles of Tolbachik volcano, named for the Itelmen people of Kamchatka.
Intro adapted from Wikipedia (CC BY-SA).
Itelmenite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Na₂CuMg₂(SO₄)₄.
It crystallizes in the orthorhombic crystal system (space group Pbca). It is a member of the Itelmenite structural group.
Key properties: Mohs hardness 2–3; specific gravity 3.1; White streak; Vitreous luster; optically biaxial.
IMA symbol Itm, IMA status: approved, named in 2015.
Occurs as sublimates on basaltic scoria near a volcanic fumarole vent (~600-610 flC.).
It is found associated with Anhydrite, saranchinaite, hermannjahnite, euchlorine, thénardite, aphthitalite, hematite.
The mineral was named to honor the Itelmens, an ethnic group who are the original inhabitants of the area around Tolbachik volcano and the Kamchatka Peninsula.