Laboratory Identification Characteristic of Purple Jadeite

Recently, the identification of purple jadeite has become more and more complicated and lacks of a systematic process. Common purple jadeite samples (including natural jadeite, bleached, filled and dyed jadeite, dyed jadeite) were collected from the market for infrared spectroscopy, ultra-depth-of-field microscope, DiamondView^TM, UV-Vis spectrophotometer and other instruments tests and analyses. The results show that in the infrared spectrum, the bleached, filled and dyed samples in the mid-infrared region show absorption peaks caused by artificial resin fillings at 3 056, 3 035, and 2 872 cm^-1. Some dyed samples in the near-infrared region have 4 327 cm^-1and 4 257 cm^-1-CH₃ and -CH₂- absorption peaks, which indicates the existence of organic matter. Dyed jadeite samples under super-depth-of-field microscope show that the dyes distribute in granular form on the surface, and vein in the interior and concentrate in cracks or depressions. Under DiamondView^TM, bleached, filled and dyed samples and dyed samples show purple and purple-red fluorescence in clumps distribute on the blue and green substrates, or only blue vein-like fluorescence can be seen. Under UV-Vis spectrophotometer, the dyed samples show absorption bands centered at 560, 600 nm or 550, 590, 650 nm. These characteristics can distinguish bleached, filled and dyed jadeite samples and dyed jadeite samples from natural samples. On this basis, the laboratory identification process can be optimized to provide a feasible basis for the laboratory to accurately, quickly and non-destructively identify purple jadeite.