Natrolite, Epistilbite and Analcime in Amygdales of Altered Anedsite from Parandak, Central Iran

Based on the field studies and thin section, XRD, SEM,and microprobe analyses data, We report, for the first time, occurrences of natrolite, tetranatrolite epistilbite and analcime in amygdales of altered andesite and andesitic-basaltic rocks, at north Parandak. Minerals associated with these zeolite are calcite, pyrolusits, hematite, opal, chalcedony and quartz. The sequence of mineral formation in the amygdales and veins are primary calcite, analcime, natrolite, mesolite, stilbite-Ca, stilbite, secondary calcite and pyrolusite. Evidences, such as analcime with low TSi and occurrence of epistilbite show that the zeolites are formed hydrothermally in this region.