In this work, synthesis studies were performed using a partially zeolitized vitreous tuff (rich in mordenite) from the province of Mendoza, with 0.1, 0.5 and 1N NaOH solutions at temperatures of 40 and 95°C. The process was monitored by X-ray diffractometry and scanning electron microscopy. Experiences showed that the material can be homogenized improving its crystallinity, transforming the relict glass and mordenite in to a Na-P zeolite of phillipsite-Na family (Na5,7Al5,7Si10,3O32.12H2O) with subordinate analcime and problable chabazite. The reaction evolution was more effective and fast ar 95ºC in 1 N NaOH solution.