This stone is a pulping plane and every archaic period chef needed one. It is a tool for rubbing back and forth on a flat surface to pulverize grains to make flour. This one is 4 in./ 102 mm X 3.25 in./ 83 mm and weighs 2 lbs. 9 oz. The core stone has been tooled to better fit the hand. The base surface has some light polishing from use and the upper surface has patination from palm handling. The pulping plane was thought to be used in grain preparation but also could have been used to break-down a fibrous material for cordage. A rare find. From the Bracken collection. Please see photos for details. (ref. Oklahoma Indian Artifacts, Bell, 1980, pp. 18, 19).