Synthetic gems possess the same chemical composition and crystal structure as natural ones but form under controlled laboratory conditions in days or weeks rather than geological time. Diagnostic features include curved growth striae and gas bubbles in Verneuil (flame-fusion) synthetics, metallic flux inclusions in flux-grown material, or seed plates in hydrothermal synthetics.
Microscopy, UV fluorescence patterns, and trace-element profiles (often lacking natural impurities) separate synthetics from natural gems. Spectroscopy confirms identical major chemistry while highlighting growth-related differences. Accurate identification ensures proper valuation and disclosure.