Water Molecules in Channels of Natural Emeralds from Dayakou (China) and Colombia: Spectroscopic, Chemical and Crystal Structural Investigations oleh Yu-Yu Zheng, Xiao-Yan Yu, Bo Xu, Ting-Ya Zhang, Ming-Ke Wu, Jia-Xin Wan, Hong-Shu Guo, Zheng-Yu Long, Lin-Yan Chen, Li-Jie Qin