gems, corundum, color.4, treatments.6, UV fluorescence

Hughes and Emmett examine ultraviolet fluorescence as a practical gemological tool for investigating the heat treatment of ruby and sapphire, particularly the relationship between fluorescence and the temperatures experienced by corundum. Heating can alter or destroy mineral inclusions and other microscopic evidence traditionally used to recognize treatment, but it can also produce systematic changes in fluorescence related to the behavior of trace elements and defects within the crystal. The authors discuss how fluorescence reactions under ultraviolet illumination can provide clues to treatment history and help distinguish corundum subjected to different thermal conditions. Particular attention is given to the scientific basis of these reactions and their practical observation, demonstrating how a simple and long-established gemological technique can yield valuable information when interpreted in conjunction with other evidence. Italian translation of the article “Heat Seeker: UV fluorescence as a gemological tool”