Identification Characteristic of Filled Phosphosiderite

Filled phosphosiderite products are common in jewelry market, but the researches on fillings and filling degree are not enough.In order to provide more evidence for gem testing, different kinds of filled phosphosiderite samples from the jewelry market are investigated by conventional gemmological methods, X-ray diffraction, infrared spectra, Raman spectra and UV-Vis spectra.Results show that samples filled heavily can be identified by different luster and fluorescence.However, samples filled slightly, which are difficult to be identified by magnification and fluorescence, need more spectroscopy measurements.In the FTIR spectra, the absorption related to the epoxy resin fillings peaked at 1 510 cm^-1 and 1 250 cm^-1 in the medium-infrared region and 5 985 cm^-1 in the near-infrared region are obvious.In the Raman spectra, the Raman shifts related to the epoxy resin at 1 112, 1 185 and 1 464 cm^-1are consistent with the FTIR test results.Moreover, in the fissure of some samples, the Raman shifts at 1 061, 1 131, 1 293 and 1 438 cm^-1 can be detected, which are due to the paraffin fillings.The UV-Vis spectra of the sample show the absorption bands at 423, 538 nm and 750 nm, which are in agreement with the untreated natural phosphosiderite.It can be inferred that the filling process has little effect on the original colour of the filled phosphosiderite samples.In a conclusion, the common filled phosphosiderite samples in jewelry market may undertake multiple filling processes, and the major fillings are colourless epoxy resin, which can be identified effectively and nondestructively by the FTIR and Raman spectra.