gems, gemology, basic gemology, advanced gemology, gem testing, spectroscopy, photoluminescence spectroscopy, PL spectroscopy

Photoluminescence (PL) spectroscopy is a powerful testing method for gemstones in which absorption of light leads to emission at longer wavelengths, revealing valuable insights into the material’s composition, structure, and optical properties. In gemology, PL is a crucial tool for identifying and characterizing gemstones, understanding their geological history, detecting treatments and synthetics, and providing clues about the presence of impurities, defects, and inclusions. The advantages and disadvantages of PL will be explored along with a survey of its applications among various gemstones including diamonds, pearls, and chromium-containing gems, with a focus on emerging techniques such as PL mapping, fluorescence lifetime, and large-scale statistical analysis. This article highlights the significance of PL spectroscopy applied to gemstones, revealing new insights into these natural wonders and helping distinguish them from their treated and laboratory-grown counterparts.