tsepinite-Ca [Ca(Ti,Nb)2(Si4O12)(OH,O)2 · 3H2O] / tsepinite-K [K2(Ti,Nb)2(Si4O12)(OH,O)2 · 3H2O] / tsepinite-Na [Na2(Ti,Nb)2(Si4O12)(OH,O)2 · 3H2O] / tsepinite-Sr [Sr(Ti,Nb)2(Si4O12)(OH,O)2 · 3H2O]