Acta Petrologica et Mineralogica

In order to improve the screening efficiency and accuracy of batch small particle diamonds, this paper developed a new type of ultraviolet photoluminescence image high-speed acquisition device—jewelry observation and identification instrument (DDO). Through the selection of excitation light source, industrial camera, structural design technology breakthroughs, and innovation in the collection method of luminescence phenomena, it achieved batch observation of photoluminescence phenomena and luminescence delay differences between different gemstones, thereby achieving efficient detection of gemstones. The DDO test results on over 20000 colorless natural diamonds, synthetic diamonds, and imitation diamonds show that 98% to 99% of colorless natural diamonds exhibit a blue phosphorescence phenomenon within 0.1~10 ms after the cessation of ultraviolet light excitation, which is a typical feature of natural diamonds. The luminescence characteristics (luminescence color, intensity, duration, structural zoning) of synthetic diamonds and other colorless gemstones are significantly different from natural diamonds. Therefore, a new method for rapid and accurate screening of colorless natural diamonds is established by observing the differences in continuous luminescence (phosphorescence) characteristics, including fluorescence and decay time within 100 ms, as screening conditions. This device improves the accuracy and detection efficiency of diamond identification, with a screening pass rate of up to 99% for natural diamonds and 100% for synthetic and imitation diamonds.

jewelry determining observation system (DDO); diamond; fluorescence; phosphorescence