Nanjing Jewelry Research and Testing Center Co., Ltd. Nanjing Jewelry Research and Testing Center Co., Ltd. can identify Laoshan sandalwood bracelets. The company's business scope is the research and testing of Laoshan sandalwood bracelets, jewels and jade. Nanjing is located in the east of China, in the lower reaches of the Yangtze River and near the river. It is the headquarters of the war zone in eastern China.