Andrianovite


Andrianovite is a very rare mineral of the eudialyte group, with formula Na126Ca63Zr3NbSi22O5. The original formula was extended to show the presence of cyclic silicate groups and silicon at the M4 site, according to the nomenclature of eudialyte group. Andrianovite is unique among the eudialyte group in being potassium-rich. It is regarded as potassium analogue of kentbrooksite, but it also differs from it in being oxygen-dominant rather than fluorine-dominant. Also, the coordination number of Na in this representative is enlarged from 7 to 9. The name of the mineral honors Russian mathematician and crystallographer Valerii Ivanovich Andrianov.

Occurrence and association

Andrianovite was discovered in pegmatites of Koashva open pit, Khibiny massif, Kola Peninsula. Russia. It coexists with aegirine, lamprophyllite, lomonosovite, microcline, mosandrite, natrolite, sodalite and villiaumite.