Thermoluminescent Characteristics of Rock Crystals and Their Significance in Gemmology

The thermoluminescent(TL) characteristics of the natural colourless rock crystal,tea-quartz,amethyst samples and their synthetic samples are tested by using the thermoluminescence metering device.The TL spectra of the natural and synthetic samples are analysed and contrasted.The results show that the natural colourless rock crystal samples have the weak thermoluminescence and the synthetic colourless samples have no thermoluminescence.The colours of both have no change after heating.The natural tea-quartz samples have no thermoluminescence and the colours do not change after heating.The synthetic tea-quartz samples have the intense thermoluminescence and clear TL spectra,and the colours change to colourless after heating.However,the colour of synthetic tea-quartz remains dark brown if only heated for 120 seconds.The natural amethyst samples have no thermoluminescence and the synthetic amethyst samples have the weak thermoluminescence.The colours of both have no change after heating.All these results show that the thermoluminescence has the special role in solving special kinds of gemstone appraisal prombles.