Cathodoluminescence (CL) measurements of clay minerals were performed at both room temperature and low temperature. Panchromatic CL images of kaolinite and dickite show blue emission at room temperature. Their CL spectra exhibit an intense broad band peak at around 375nm. This emission band related to radiation induced defect centers (RID) disappears at low temperature. Effect of sample temperature on CL intensity of kaolinite and dickite can not be interpreted on the basis of a temperature quenching theory. In halloysite, serpentine minerals, sericite and sepiolite, the intensity of a broad band between 400 and 450nm is higher at low temperature than at room temperature. CL spectra of serpentine minerals are characterized by a broad band centered at 720nm, which can be assigned to Fe³⁺ impurity center.
Natural TL glow curve of sepiolite presents two glow peaks around at 210 and 260°C in the high temperature region, of which intensities are weak. This implies that it is rather a possibility of applying TL of sepiolite to the dating. The other minerals show no emission in natural TL measurements. X-ray induced TL of kaolin minerals exhibit intense several TL glow peaks below room temperature. Serpentine minerals have glow curves with a relative large peak between 70 and 90°C. Sericite, montmorillonite and sepiolite show a combination of emission peaks in their TL glow curves, while their intensities are weak compared to kaolin and serpentine minerals. Clay minerals might have characteristic TL related to their crystal structure.