Georgbarsanovite is a very rare mineral of the eudialyte group,[1] formerly known under unaccepted name as barsanovite, with formula Na12(Mn,Sr,REE)3Ca6Fe32+Zr3NbSi(Si3O9)2(Si9O27)2O4Cl2·H2O.[2] The original formula was extended to show the presence of cyclic silicate groups and domination of silicon at the M4 site.[3] "REE", standing for rare earth elements, are dominated by cerium.