Comparative Study of Mineralogical Characteristics of Natural and Synthetic Amethyst and Smoky Quartz

With the development of synthetic gem technology, a large number of synthetic rock crystals, such as natural and synthetic amethyst and natural and synthetic smoky quartz, have emerged in the market. Research on how to identify natural and synthetic amethyst, and natural and synthetic smoky quartz is of great significance. This paper systematically studied the mineralogical characteristics of natural and synthetic amethyst and natural and synthetic smoky quartz through X-ray powder diffraction, energy spectrum analysis, infrared spectroscopy, Raman spectroscopy, and ultraviolet visible light absorption spectroscopy. The results showed that the basic gemstone properties of natural and synthetic amethyst, natural and synthetic smoky quartz were very similar. The synthetic amethyst and smoky quartz could be seen bending cracks, with a small amount of bread crumb-like black inclusions under the polarizing microscope. Natural amethyst and smoky quartz had Raman characteristic peaks of about 697 cm−1 and 1160 cm−1, while synthetic amethyst and smoky quartz had no vibration peaks in these bands. Compared with the synthetic amethyst, the natural amethyst lacked the characteristic infrared absorption peak of 3500 cm−1; compared with natural smoky quartz, synthetic smoky quartz lacked the 3484 cm−1 infrared absorption peak.