Raslakite


Raslakite is a rare mineral of the eudialyte group with the formula Na15Ca3Fe33Zr3SiO223. This formula is based on the original one, and is extended to show the presence of cyclic silicate groups. The additional silicon and oxygen shown in separation from the cyclic groups are in fact connected with two 9-fold rings. The mineral has lowered symmetry, similarly to some other eudialyte-group members: aqualite, labyrinthite, oneillite and voronkovite. The specific feature of raslakite is, among others, the presence of sodium and zirconium at the M2 site. Raslakite was named after Raslak Cirques located nearby the type locality.

Occurrence and association

Raslakite was discovered, together with ikranite, in peralkaline pegmatites of the Mt. Karnasurt, Lovozero massif, Kola Peninsula, Russia. Raslakite is associated with aegirine, fluorcaphite, kazakovite, lamprophyllite, microcline, nepheline, and terskite.