jade, jadeite, fei cui, treated jade, FTIR, B jade, gems

Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy has been found to be a useful and non-destructive tool for providing evidence of bleached and wax-or polymer-impregnated jadeites (Grade B jade). Therefore, the natural and untreated jadeites and those which are wax-buffed (Grade A jade) can be reliably discriminated. The strong absorption peaks shown on the DRIFT spectra can be used to test for the presence of polymers and wax. Results of a systematic DRIFT study done on 10 jadeite samples show that some of them have been bleached and wax-or polymer-impregnated. The DRIFT results, which were backed by basic gemmological tests and X-ray photoelectron spectroscopy (XPS), were compared to similar studies by Fourier transform infrared (FTIR) transmission spectroscopy. In comparison, DRIFT spectroscopy has advantages limited to the testing of very thick (greater than 12 mm) jadeite samples and of relatively thin pieces of Grade A jadeite which may not be very transparent to infrared radiation. It also has an advantage for jadeite jewellery with completely closed mountings, which is rare.