Crystallochemical aspect of clay and clayish matter minerals luminescence

X-ray luminescence (XRL) spectra in optical range of wave-lengths and thermoluminescence (TL) curves of several clay and clayish matter minerals were recorded for the first time. Mineral composition of all the samples was determined on the base of X-ray diffraction results. It was stated that XRL of clay minerals is related to their crystallochemical characteristics (type and degree of regularity of structure and isomorphism occurrence in particular). In the opinion of the authors, differences between luminescent characteristics of halloysite and kaolin minerals are related to syngony (triclinic or monoclinic) and possibility of Si4 + substitution with Al3 + in tetrahedral coordination that lead to uncompensated charges appearing and formation of luminescence centres based on silicon and aluminium tetroxides.