T208 Gemological Research in the 21st Century: Gem Minerals and Localities

Thursday, 29 October 2020
1:30 PM - 5:30 PM
Meeting Rooms

APPLICATION OF THREE-DIMENSIONAL FLUORESCENCE SPECTROSCOPY IN THE IDENTIFICATION OF JADEITE

Paper number: T208-14
Program: Technical Sessions
Time: 4:25 PM – 4:35 PM

Authors

  • Ping Ma Presenting Author
    GemmologicalInstitute, Wuhan
  • Ping Ma Presenting Author
    Wuhan, None

Abstract

This article comprehensively collects samples of natural jadeite (A jadeite), bleached or glued jadeite (B jadeite), dyed jadeite (C jadeite), and bleached or glued dyed jadeite (B+C jadeite) on the market。Use a three-dimensional fluorescence spectrophotometer as the main test and analysis method to analyze the three-dimensional fluorescence spectrum characteristics of the samples. Except that the natural untreated jadeites (A jadeite) has no fluorescence reaction,1.Bleached or glued jadeites (B jadeite) is added with aromatic compounds such as epoxy resin in the process. B jadeite has a strong luminous center in the three-dimensional fluorescence spectrum of 380nm(λEx)/440nm(λEm), 380nm( λEx)/339nm(λEm).2. Dyed jadeite (C jadeite) is dyed with organic dyes, and the fluorescence produced is weaker than that of B jadeite. The fluorescence center is 365nm(λEx)/443nm(λEm).3. Bleaching or plastic injection dyeing purple jade (B+C jadeite) is filled with organic dyes and resins, and the fluorescence center is 365(λEx)/443nm(λEm). The fluorescence intensity is stronger than that of C jade, and the fluorescence center is consistent.4. Bleaching or plastic injection dyeing of green jade (B+C jadeite). Due to the addition of chromium salt dye, metal ions may react with the resin to form non-fluorescent ligands, resulting in quenching of the fluorescence of the fluorescent ligands, and the fluorescence intensity is relatively low, the fluorescence peak is 285(λEx)/308nm(λEm),290(λEx)/308nm(λEm).5. B+C yellow and red jadeite has low fluorescence intensity due to the addition of iron oxide dye 。The content of yellow B+C jadeite metal dye is less than that of red B+C jadeite , and the fluorescence peak value is 335(λEx)/377nm(λEm)，The fluorescence peak of red B+C jadeite is 290(λEx)/308nm(λEm). Three-dimensional fluorescence spectroscopy is helpful to characterize resins, organic dyes and metal dyes. It has important typographical significance for the identification of jadeite varieties with different treatments.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-358983

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