Alluaivite
Alluaivite
Alluaivite is an exceedingly rare mineral of the eudialyte group, with complex formula written as Na19(Ca,Mn)6(Ti,Nb)3Si26O74Cl·2H2O. It is unique among the eudialyte group as the only titanosilicate (other representatives of the group are usually zirconosilicates). References
https://en.wikipedia.org
https://en.wikipedia.org/wiki/Alluaivite
http://www.mindat.org/min-141.html