Inclusions represent one of the most diagnostic internal features in gemstones and constitute a fundamental criterion in species identification, origin determination, and treatment detection. Their mineralogical, morphological, and optical characteristics provide clues about the physicochemical conditions under which host gems formed  As naturally occurring microstructures, inclusions serve as a “micro-geological archive,” linking gemology to petrology, fluid chemistry, and crystal growth mechanisms. Recent advances in analytical techniques such as Raman spectroscopy, FTIR, SEM-EDS, and advanced photomicrography have enhanced the ability to classify inclusions with higher precision.

This section synthesizes the role of inclusions in gemstone identification, focusing on their classification, genetic significance, diagnostic optical responses, and their utility in distinguishing natural, synthetic, and treated stones. Case studies for diamonds, corundum, emerald, garnet, and quartz illustrate practical applications of inclusion analysis.