Brownish crystal aggregates of the very rare mineral vladykinite from the TL in Russia (Malyi Murun Massif, Irkutsk Oblast, Russian Federation) and only one of two known localities worldwide. Ex. Erich Laskowski collection (USA). — Photo: David Hospital · CC BY 4.0
Vladykinite
Vladykinite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₃Sr₄(Fe²⁺Fe³⁺)Si₈O₂₄.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 5; specific gravity 3.22; White streak; Vitreous luster; optically biaxial.
IMA symbol Vdy, IMA status: approved, named in 2011.
An early magmatic phase in a dike of coarse-grained feldspathoidal syenite (lujavrite) in an alkaline igneous complex.
It is found associated with Aegirine, potassium feldspar, eudialyte, lamprophyllite, nepheline.
The mineral was named to honor Nikolay V. Vladykin (b. 1944), Vinogradov Institute of Geochemistry, Irkutsk, Russia, for his contributions to the study of alkaline rocks.