Voronkovite
Voronkovite is a very rare mineral of the eudialyte group with the formula Na1533Fe3Zr3Si2Si24O724Cl·H2O. The formula is based on the simplified original one; it does not show the presence of cyclic silicate groups, but two M3- and M4-site silicon atoms are shown separately. Voronkovite has lowered symmetry, similarly to some other eudialyte-group members: aqualite, labyrinthite, oneillite and raslakite. The specific feature of voronkovite is, among others, strong enrichment in sodium.Voronkovite comes form an ultra-alkaline pegmatite of Mt. Alluaiv, Lovozero massif, Kola Peninsula, Russia. It associates with aegirine, lomonosovite, manganoneptunite, microcline, nepheline, shkatulkalite, sodalite, terskite, sphalerite and vuonnemite.
