Voronkovite
A very rare eudialyte-group mineral with separated silicon sites in its complex formula.
Intro adapted from Wikipedia (CC BY-SA).
Voronkovite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₁₅(Na,Ca,Ce)₃(Mn,Ca)₃Fe₃Zr₃Si₂₆O₇₂(OH,O)₄Cl·H₂O.
It crystallizes in the hexagonal crystal system (space group R3). It is a member of the Eudialyte structural group.
Key properties: Mohs hardness 5; specific gravity 2.97; White streak; Vitreous luster; optically uniaxial.
IMA symbol Vrk, IMA status: approved, named in 2007.
Found in a lenticular zoned pegmatite hosted by poikilitic nepheline-sodalite syenite in the middle part of a differentiated alkaline complex.
It is found associated with Microcline, sodalite, nepheline, aegirine, terskite, lomonosovite, vuonnemite, shkatulkalite, manganoneptunite, sphalerite.
The mineral was named to honor Russian crystallographer Alexander Alexandrovich Voronkov (1928-1982).