Lecture by Dr David C Anderson, to the Royal Geographical Society (Hong Kong), March 12th 2013. David is author of 'Hongshan Jade Treasures- the art, iconography and authentication of carvings from China's finest Neolithic Culture' (ISBN 978-88-6244-215-2, Tau Editrice). The Hongshan Culture dates to around 3,500 - 2000 BCE. In this talk he introduces carvings in 'shui jing' glass, which have been flooding into markets in China and Hong Kong, and onto ebay. He presents evidence that this is a natural glass similar to Libyan Desert Glass and that the Hongshan jade carvers using alluvial impact diamond sand as abrasive. He describes two expeditions to what he believes is a candidate impact site, and presents an hypothesis which can be best tested by mapping the sources of shui jing that is clearly still being mined and carved in Northern China.