Thermoluminescent Mechanism in Lilac Spodumene

In the present work the thermoluminescence of a lilac α-spodumene (LiAlSi$\text{}_{2}$O$\text{}_{6}$), a natural mineral from Brazil, was investigated. Toward this aim the gamma irradiation, as well as several heating processes were carried out. The sample presented a glow curve with various thermoluminescence peaks. Emission spectrum showed only one prominent band at 610 nm, which indicates the existence of only one recombination center despite the several thermoluminescence centers exhibited, due to intrinsic defects. Using correlation between thermoluminescence and optical absorption techniques we discuss the effects of gamma radiation and annealing in the lilac spodumene, and conclude that an annealing at about 230ºC can be applied to natural lilac spodumene gems used in jewelry for increment of its lilac color.