Gemmological Characteristic of Barite Jade(Treated)

Recently the authors received 4 samples which were claimed to be "Qinghua jade". The samples were tested by conventional gemmological tests and polarizing microscope, X-ray powder diffraction, Fourier transform infrared spectrometer, Raman spectrometer, SEM and EDS. The test results showed that the refractive index range of the sample measured by gem refractometer is 1.63-1.64 (point measurement) and the relative density is about 4.17-4.20. Meanwhile, it showed weak fluorescence under long wave ultraviolet. Polarizing microscope test showed that the sample is mainly composed of a large number of barites, mixed with trace amounts of azurite, malachite and opaque metallic minerals. According to X-ray powder diffraction analysis, it showed that the main mineral component is barite. Raman spectrum showed, that the blue part of the sample is azurite, and the greenish blue basement is barite. There are small cracks on the surface of the sample where the synthetic resin brown lens body can be seen. This indicates that the sample has been filled with synthetic resin in the later stage. According to the GB/T 16552-2017, the sample is recommended to be named as barite jade (treated), and note that it contains azurite partially.