Crystal of the very rare mineral ershovite from the type locality (Koashva Mountain, Khibiny Massif, Kola, Russian Federation) and only two known localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Ershovite
Ershovite is an IMA-recognized mineral species in the silicate class, with the chemical formula K₃Na₄(Fe,Mn,Ti)₂Si₈O₂₀(OH,O)₄·4H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Ershovite structural group.
Key properties: Mohs hardness 2–3; specific gravity 2.75; White streak; Vitreous luster; optically biaxial.
IMA symbol Esh, IMA status: approved, named in 1991.
Found in unweathered ultra-agpaitic pegmatites in a differentiated alkalic massif.
It is found associated with Orthoclase, nepheline, sodalite, aegirine, alkalic amphibole, villiaumite, natrite, rasvumite, vuonnemite, astrophyllite, shcherbakovite, kazakovite.
The name refers to Professor Vadim Victorovich Ershov (1939–1989), of the Moscow Mining Institute, Moscow, Russia.