Abstract：Fresh water nucleated cultured pearls with large grain size, high roundness and rich color (the commercial name is “Edison” Pearl) provide higher quality and value for the pearl market. However, due to the trend of interests, dyed nucleated cultured pearls gradually flow into the market, which disturbs the healthy consumption of consumers and hinders the sound development of “Edison” pearl industry to a certain extent. In this paper, infrared spectrometer, ultraviolet-visible spectrophotometer and photoluminescence spectrometer were used to systematically study the spectra of cultured and dyed “Edison” pearls and compared with seawater pearls and dyed seawater pearls. The results showed that: (1) the dyed and cultured “Edison” pearls showed aragonite vibration peaks at 1 445, 882 and 725 cm-1 in the infrared spectrum, and the dyed “Edison” pearls showed a broad and weak absorption peak at 3 800 cm-1; (2) The absorption peak at 280 nm of dyed “Edison” pearls is obviously weaker than that of cultured “Edison” pearls, which may be related to the damage of protein molecules in pearls caused by dyes. After dyeing, the overall reflectivity of “Edison” pearls decreased. Dyed yellow “Edison” pearl lacks the absorption peak at 360~380 nm of cultured orange-yellow “Edison” pearl, which is similar to the strong absorption peak at 430 nm of dyed seawater gold beads. Dyed black “Edison” pearls have absorption peaks at 425 nm, dyed sea water black pearls have absorption peaks at 480 and 645 nm, and cultured sea water black pearls have absorption peaks at 702 nm. The difference between the three patterns may be due to their different dyes; (3) A group of absorption peaks can be seen in the range of 450~550 nm in the photoluminescence spectrum of cultured “Edison” pearls. The luminous center of dyed “Edison” pearls shifts to the red zone, and absorption peaks related to dyes appear around 650 nm with different intensities. Dyed seawater gold beads also have absorption peaks related to dyes at 600 nm.
于 蕾，王雅玫. “爱迪生”珍珠及染色处理有核珍珠的谱学特征[J]. 光谱学与光谱分析, 2021, 41(08): 2626-2632.
YU Lei, WANG Ya-mei. The Spectral Characteristics of “Edison” Pearls and Nucleated Pearls With Dyeing Treatment. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(08): 2626-2632.
