The Nan Yang Gemological Institute, NGI, first published the Gems of the World Chart in 2007, making it available in both English and Chinese languages. This comprehensive chart showcases various gems, classified according to their species and varieties, including inorganic, organic gems, Jadeite, and jadeite simulants. In addition, the chart provides essential gemological information, such as Refractive Index (RI), Birefringence (DR), Specific Gravity (SG), and Hardness (H). Its high-quality content has garnered acclaim from the gem and jewellery industries, as well as renowned gemological institutes worldwide, making it a valuable educational resource.
You may collect a copy of the Chart free of charge at the NGI office.
NGI is in the process of updating the chart.
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