Turkey clinoptilolite-rich tuffs from Gordes and Bigadi double dagger regions of western of Anatolia and their exchanged forms (K(+), Na(+), Mg(2+) and Ca(2+)) were characterized by TG/DTG-DTA, DSC and XRF methods and the surface areas were also determined for both tuffs. TG-DTG and DTA curves of all clinoptilolite samples were measured in the temperature range 30-1000 A degrees C. All clinoptilolite samples had major, rapid mass losses between 30 and 200 A degrees C, with slower and less significant mass losses at higher temperatures. The mass loss of the Natural-G is 9.54% while that of the Natural-B sample is 10.50%. Water content increases in the order of K < Na < Ca < Mg for Bigadi double dagger clinoptilolite samples and in the following sequence K < Na < Mg < Ca for Gordes clinoptilolite samples. One mass loss step for all clinoptilolite samples was observed using differential scanning calorimeter (DSC) in the range of 30-550 A degrees C.