浅表层加色处理金色海水珍珠的谱学鉴别特征

Spectral Identification Characteristics of Superficial-layer Dyed Golden Seawater Cultured Pearls

  • 摘要: 目前,国内珍珠市场中染色处理的金色海水珍珠的染料类型尚不明确,鉴别难度大。通过对一些浅表层加色处理金色海水珍珠样品的表面特征、紫外-可见光谱、拉曼光谱研究发现,浅表层加色处理金色海水珍珠的剖面特点与金色海水珍珠的一致,剖面珍珠层的颜色由内向外颜色变浅,同心环状分布,这与传统染色处理金色海水珍珠的剖面特征不同。浅表层加色处理金色海水珍珠的紫外-可见吸收光谱具有398nm处的吸收峰,是由人工染料造成的特殊吸收峰,具有鉴定意义;浅表层加色处理金色海水珍珠的拉曼光谱和金色海水珍珠的一致,且没有传统染色处理金色海水珍珠拉曼光谱的强荧光背景,可能是染料沉淀极少所致。

     

    Abstract: The dyestuff types of dyed golden seawater cultured pearls in the jewelry market are still unknown at present,which makes its identification more difficult.The superficiallayer dyed golden seawater cultured pearls are studied by UV-Vis spectrophotometer,Raman microspectrometer,and gem microscope.The results show that the section characteristic of superficial-layer dyed golden seawater cultured pearls are similar to those of golden seawater pearls,whose colour is getting lighter from inside to outside(orange to yellow to faint yellow)and concentric nacreous layers are different from those of traditional dyed golden seawater cultured pearls.The phenomenon of dye enrichment only appears in tiny blemish and no dye enrichment on the surface nacreous layers in superficial-layer dyed golden seawater cultured pearl samples,and their surfaces become faint yellow after repolishing.The diagnostic absorption peak at 398nm in UV-Vis spectrum related to the artificial dyeing agent is only found in the superficial-layer dyed golden seawater cultured pearl samples,and not found in the repolishing facet,section or golden seawater cultured pearls.Raman spectra of superficial-layer dyed golden seawater cultured pearls are the same as those of the golden seawater cultured pearl.Compared with the traditional dyed golden seawater cultured pearl with strong fluorescence background in Raman spectra,the superficial-layer dyed golden seawater cultured pearls do not have strong fluorescence background,whose artificial dyeing agent is too little to cause obvious fluorescence background in Raman spectra.It can't be used to judge the pearl dyed according to the fluorescence background.

     

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