V ietnam, with an area of 335,000 km 2 , occupies the eastern side of the Indochinese peninsula. Most of the country's northern and central regions are mountainous, reaching an elevation of 3,142 m in the Fan Si Pan massif, near the Chinese border. The country is endowed with some 70 gem deposits and 160 different occurrences (Nguyen et al., 1995). Present gem production includes ruby, sapphire, spinel, tourmaline, peridot, garnet, aquamarine, topaz, quartz, and green orthoclase (e.g., figure 1). With more than 3,400 km of coastline, the country is also a source of saltwater cultured pearls, and several farms have emerged in recent decades. In addition, Melo pearls are retrieved by fishermen on the southern coast and in Ha Long Bay in the north. Compared with the country's gem wealth, however, the Vietnamese mining industry remains undeveloped. Although it has been nearly 30 years since colored stones were discovered in Vietnam, mining and pearl farming activities are mostly small-and medium-scale operations run by private individuals or small companies. In March 1988, state-owned Vinagemco (Vietnamese Gems Company) was established to direct the exploration, mining, and trading of gem materials (Kane et al., 1991; Pham et al., 2004b). Two subsidiaries, Yen Bai Gemstone Company and Nghe An Gemstone Company, were set up in those provinces that same year. Ultimately, management problems led to the company's downfall in July 2003. Since then, no state-owned company has been active in the gem sector. Mining, processing, cutting, and trading are all organized by private and joint-stock companies or private individuals. Scientific investigations of Vietnamese gem materials, including their properties and the genesis of the deposits, have resulted in several publications, with special attention to ruby and sapphire (e.g.,
