Vigrishinite
Vigrishinite is an IMA-recognized mineral species in the silicate class, with the chemical formula NaZnTi₄(Si₂O₇)₂O₃(OH)(H₂O)₄.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Seidozerite-Murmanite structural group.
Key properties: Mohs hardness 2.5–3; specific gravity 3.03; White streak; Vitreous luster; optically biaxial.
IMA symbol Vig, IMA status: approved, named in 2011.
Found in a zoned peralkaline pegmatite located in foyaite and lujavrite rocks of a layered alkaline igneous complex. Found at the periphery of the ussingite core near its contact with the aegirine-eudialyte zone.
It is found associated with Microcline, ussingite, aegirine, analcime, natrolite, gmelinite-Na, gmelinite-K, chabazite-Ca.
The mineral was named to honor the Russian amateur mineralogist and mineral collector Viktor G. Grishin (b. 1953) for his significant contribution to the mineralogy of the Lovozero complex, Russia.