Raslakite is a rare mineral of the eudialyte group with the chemical formula Na15Ca3Fe3(Na,Zr)3Zr3(Si,Nb)SiO(Si9O27)2(Si3O9)2(OH,H2O)3(Cl,OH).

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 (in parentheses) are in fact connected with two 9-fold rings.

Raslakite is associated with aegirine, fluorcaphite, kazakovite, lamprophyllite, microcline, nepheline, and terskite.

[3] Beside main elements given in the formula, raslakite contains some potassium, strontium, manganese, magnesium, cerium, titanium, and aluminium, with minor amounts of lanthanum and hafnium.