Sodium fluorohectorite Na-0.6[Mg2.4Li0.6]Si4O10F2 was synthesized from the melt in an open glassy carbon crucible at 1265 degrees C under argon flow. A glass (Na2O-Li2O-SiO2) precursor was used as a fluxing agent in order to maintain a low vapor pressure of volatile fluorides and sustain a low silica activity, which inhibits the formation of silicon fluoride gases and promotes the fluorine solubility in the melt.