Amygdaloidal Zeolites in Volcanic Rocks, Shahrood Province, North Central Iran

Tetranatrolite and natrolite are generally fibrous and acicular and more abundant than analcime and stilbite at Meyamey in Shahrood province. Amygdaloidal zeolites of the Meyamey area are spheroidal, ellipsoidal, and grotesquely-shaped. Their dimensions range from millimeter to centimeter. The zeolites in the Gardaneye Chah-Mora and Kuh-e-Kahovan of the same province are mostly natrolite which is associated with calcite. The host rocks of the zeolites are consist of trachyandesite, andesite, chloritized andesite and porphyritic andesi-basalt. In the Meyamey area the zeolites are found in agglomerate. Such co-existing of zeolites in agglomerates was not reported in other localities in Iran yet.