Karl Polanyi's discussion of the commodification of land, labour, and money is useful in analysis not only of nineteenth century markets but also of twenty-first century social and economic developments. This working paper explores the process of commodification of tanzanite, a gemstone discovered in the 1960s south of Mt. Kilimanjaro, Tanzania, and actively mined only since the 1980s. More rare than diamonds because the source area is limited to the Mererani hills east of Arusha, the gemstones reach markets through Maasai middlemen, foreign buyers, processors, cutters, polishers and dealers in Tanzania, India, Hong Kong, and the United States. The U.S. is responsible for 80% of the market for tanzanite. Production of the stone is occasionally slowed by flooding, accidents, and conflict over rights to mining areas. Children and teenagers often work in the tanzanite mines. These miners suffer death and disease not only because of unsafe mine conditions but also because of drug use and HIV/AIDS. Furthermore, this new commodity received close scrutiny after the attacks of September 11, 2001, because of a Wall Street Journal report that members of al Qaeda bought tanzanite for use in funding its networks and activities. This paper explores policy issues raised not only by that report and by global NGOs such as Global Witness, but also by the Tanzanian state, by health and safety workers and the miners and mining companies at Mererani. The paper is based on field interviews with buyers and sellers, in Tanzania and in the United States, as well as analysis of media reports, in order to argue that this particular commodity is, in Polanyi's terms, a fiction, one which has serious policy, social, health, and economic implications.