JNA Nov/ Dec 2020

創新科技 JNA Nov/Dec 2020 | 37 GIA is also launching a new smaller and more affordable Cultured Pearl Classification Report. It contains a detailed classification of each of the GIA 7 Pearl Value Factors TM , which provide a systematic way to evaluate pearls of all types and to simplify pearl quality descriptions. The seven factors are size, shape, colour, nacre, lustre, surface and matching. These are specifically and exclusively for Akoya, South Sea and Tahitian pearls. The new report will first be made available in New York and subsequently rolled out in other locations. GIA recently tested two pearls that proved challenging to identify due to trace element anomalies. According to GIA, pearl testing is almost always relatively straightforward, but the need for more sophisticated methods to detect and classify different cases is apparent. “While it is important to continue our research on modern identification tools and techniques, it is also necessary to understand that pearls are created by living organisms, which may exhibit unusual gemmological, physical and chemical properties based on their living conditions and biological responses to irritation. Oddity will always exist in nature, which can create challenging and intriguing specimens,” noted Zhou. Continuous innovation is likewise a top priority at SSEF, with the launch of its DNA testing technology for pearls in June this year. According to Laurent E. Cartier, project manager at SSEF, the gem lab was the first to introduce DNA testing of pearls to conclusively identify their species. This new approach to pearl testing was met with positive response from the industry. SSEF can also provide DNA testing for ivory and precious corals. The new service, which uses DNA fingerprinting technology, was developed in partnership with the Institute of Forensic Medicine at the University of Zurich. It is an expansion of SSEF’s DNA fingerprinting reference database and capabilities, which now include eight oyster species that produce the majority of pearls found in the natural and cultured pearl trade. The quasi non-destructive method has since been refined further, and the amount of material required from the pearl for testing has been considerably reduced to an infinitesimal amount, the gem lab said. In 2017, SSEF introduced radiocarbon age dating of pearls, which made waves across the trade, especially for high- end natural pearls. “We have dated some exceptional historic natural pearls using this method in recent months and years. Such previously unavailable information provides important insights and documentation into the history and provenance of a pearl,” revealed Cartier. Over the past few decades, SSEF has analysed outstanding natural pearls in the market. These include the La Peregrina pearl, a massive natural pearl discovered in the 16 th century and previously owned by members of various royal families and Hollywood actress Elizabeth Taylor. The pearl was sold to an anonymous buyer for US$11 million at a 2011 auction. Radiocarbon age dating of pearls from the Cirebon shipwreck, dating them back to the 10 th century. Photo courtesy of SSEF 採用放射性碳定年法鑑定發生於十世紀時期， 井里汶沉船中發現的珍珠 圖片鳴謝： SSEF Fluorescence spectroscopy could be a quick and easy tool to separate naturally coloured pearls (right) from colour-treated pearls (left) as shown in a recent study by GIA. Photo by Sood Oil (Judy) Chia / GIA 根據 GIA 最近的研究顯示，熒光光譜法可 說是最快捷、簡易的方法從經過顏色處理 的珍珠(左邊)中辨識天然顏色的珍珠(右邊) 圖片： Sood Oil (Judy) Chia / GIA