The thermoluminescence between − 180 and 400°C of fundamental clay minerals groups kaolinite, halloysite, montmorillonite (bentonite, hectorite, pyrophyllite), talc and illite have been studied. The thermoluminescence of anhydrous and hydrated amorphous silica, quartz, cristobalite and alumina have also been studied. Each clay mineral group showed a characteristic glow' curve. All the thermoluminescent peaks of the clay minerals, except the peak at 145°C in montmorillonite, coincided with the quartz and alumina peaks. Most of the observed thermoluminescent peaks are attributed to fundamental structural units of the clay minerals.