A study of temperature effects and shrinkage properties of three clays was reported. The clay properties were studied using XRD, DTA, and TG analysis. The correlation between the volume change and temperature, depended on the structure of the colloidal system of the clay. The presence of granular nonclay grains opened up the structure for easier escape of the water, decreased the amount of water-adsorbing surfaces and provided a structure that decreased the amount of shrinkage. The clay specimen obtained from the glass factory had a more dispersed structure than did kaolinite and Bentonite specimens.