Tienshanite

Tienshanite, named for the Tian Shan Range in Mongolia, is a rare borosilicate mineral, though rock-forming in some parts of its original locality at the Dara-i-Pioz Glacier in Tajikistan. Its formula is extremely complex: KNa3(Na,K,[])6(Ca,Y,RE)2Ba6(Mn(2+),Fe(2+),Zn,Ti)6(Ti,Nb)6Si36B12O114[O5.5(OH,F)3.5]F2.