Fluorspar, this month’s featured mineral resource commodity, has been widely used in steelmaking since the introduction of basic open-hearth furnace technology in the late 19th century. Its uses have grown and changed over the last 100 years, and now fluorspar’s most important markets are fluorochemicals, aluminum refining and steel. M. Michael Miller, Fluorspar Commodity Specialist for the U.S. Geological Survey, has prepared the following information about fluorspar.