This video shows how different sedimentary rock types folded into distinct structures control topography in the Ouachita Mountains of Arkansas and Oklahoma. The chert, or novaculite, ridges in this area are sources of raw materials for making the world's finest natural sharpening stones. Novaculite is essentially slightly recrystallized chert, and the extremely high silica content and fine grain produce an outstanding abrasive stone for honing fine edges onto steel tools. These whetstones are often sold as "Arkansas Stones" or "Ouachita (Washita) Stones," and have been produced in the area since the early 19th century. The original users of the material were, of course, Native Americans in the region, who produced exceptional points and cutting tools from the conchoidally-fracturing novaculite.
