Professional buyers should request a Burn Test report or perform one on samples: genuine silk burns slowly, smells like burning hair, and leaves a crushable black ash, whereas synthetics like nylon or polyester melt and smell like plastic. Additionally, check the luster; real silk has a multi-dimensional sheen that changes color slightly depending on the light angle, while synthetic fibers often have a static, metallic shine. Always verify the Momme weight if the product uses woven silk panels, though for hosiery, the Denier and silk-to-synthetic ratio are the primary quality indicators.