Corundum, USA.12, North Carolina.12, gems

Lewis presents a detailed study of the corundum deposits and associated basic magnesian rocks of western North Carolina, describing their geographical distribution, geology, mineralogy, and economic importance. He traces a belt of peridotitic and related rocks through the region and examines the relationship of corundum to these ultrabasic bodies and their altered products, including serpentine and talcose rocks. Individual mines and prospects are described, together with the occurrence, character, and quality of their corundum and associated minerals. Lewis discusses the geological origin of the deposits, the alteration of the enclosing rocks, and the manner in which corundum occurs in veins and contact zones. Attention is also given to mining methods, production, and the commercial use of corundum as an abrasive, as well as to crystals and colored varieties of mineralogical or gemological interest. The bulletin provides an important late nineteenth-century account of the Appalachian corundum belt and its relationship to the basic magnesian rocks of western North Carolina.