Gemmological Characteristic of “Jinlinshi” (Lepidolite Jade)

The gemmological characteristics, mineral components, chemical compositions of “Jinlinshi” called by salers were researched by the conventional gemmological tests, scanning electron microscope (SEM), polarizing microscope, Fourier transform infrared spectrometer (FTIR), X-ray energy spectrometer (EDS), X-ray powder diffraction spectrometer (XRD), laser Raman spectroscopy (Raman), etc. The results showed that the refractive index of “Jinlinshi” sample is 1.55 (point measurement), and Mohs hardness is 2-3, and relative density is 2.83. FTIR and Raman test results agreed with spectrum of mica.The analysis of SEM indicated that the “Jinlinshi” sample is mineral aggregate, which has perfect cleavage, uneven fracture and scale crystalloblastic texture. EDS results showed that the “Jinlinshi” sample is mainly composed of Si, Al, K, F and O, etc. The analysis of polarizing microscope and XRD results showed that the “Jinlinshi” samples are mainly composed of lepidolite and minor muscovite, which are closely contacted and randomly arranged. According to GB/T 16552-2010 Gems─Nomenclature, the “Jinlinshi” sample should be named as “Lepidolite jade”. The interal gridded fracture of “Jinlinshi” sample showed strong blue and white fluorescence under long wave ultraviolet, which is different with the weak violet fluorescence of “Jinlinshi” sample. By microscope, the difference of the surface gloss of fracture was obvious, with the dense bubble group. It can be concluded that the “Jinlinshi” samples were filled.