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- Title
CHARACTERISTICS OF COATED JADEITE JADE.
- Authors
Jian Zhang; Taijin Lu; Hua Chen
- Abstract
Ten coated jadeite jade samples were investigated by standard gemological testing, DiamondView imaging, confocal laser scanning microscopy, and spectrophotometry, including visible-range, FTIR, and Raman. The light green coating’s Mohs hardness and refractive index were much lower than that of uncoated jadeite. Portions of the coating had peeled off in some cases, exposing the true color of the jadeite below. Measurements using a confocal scanning microscope indicated an average coating thickness of about 16 µm. DiamondView observations revealed a difference in fluorescence reaction between the surface coating and the jadeite beneath it. Visible-range spectroscopy showed a weaker broad band at approximately 630 nm and a moderate peak at 437 nm, without the approximately 691 nm band found in untreated jadeite containing chromium. The coated samples’ FTIR spectra contained four characteristic bands at about 2856, 2873, 2928, and 2958 cm–1 , while the Raman spectra showed a broad band near 2000 cm–1. These results indicated the presence of an organic polymer in the coating material.
- Subjects
JADEITE (Petrology); SCANNING electron microscopy; REFRACTIVE index; CHROMIUM; FOURIER transform infrared spectroscopy; RAMAN spectroscopy
- Publication
Gems & Gemology, 2013, Vol 49, Issue 4, p246
- ISSN
0016-626X
- Publication type
Article
- DOI
10.5741/GEMS.49.4.246