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Dr. Gamini Zoysa, Ceylon Gemmological ServicesSri Lanka has long been known as one of the world’s most important gem producing countries. Specially as a leading source for fine quality Blue Sapphires &#38; its other varieties. The genesis of gemstones in Sri Lanka has been a subject for much discussion. The gems are mostly mined from the alluvial deposits underlain by Precambrian metamorphic rocks. The main gem bearing areas are confined to the geological division called highland complex which is located in the central part of the country. Over 3200 legal gem mines have been in active operation in the past years. The depth of the gem gravel in a shaft may vary from 10 to 25 meters. There are also evidences for occurrence of primary deposits of Sapphire, Moonstone , Aquamarine, Garnet within the island. In addition to the major commercially viable gem varieties such as Sapphires, Garnet, Chrysoberyl, Topaz, Zircon, Moonstone, Tourmaline, Beryl, Quartz there are over 80 varieties of nontraditional gems are recorded.Dienstag, den 25. Oktober, 18.15 UhrRömisch-Germanisches Zentralmuseum – VortragssaalIm Rahmen der Vortragsreihe "Weltweites Zellwerk"See the full program here!&#160;Foto: (c) http://www.aigsthailand.com