Characteristics of Lithic Sound to Assess a Rock’s Predictability of Flaking

ABSTRACT It has been suggested that a lithic resource’s candidacy for predictability of fracture when knapped, and whether or not a stone has been heat treated, can be assessed by the duration, pitch, and loudness of sound made when a stone is struck. A hammer stone machine held and struck specimens of 16 lithic types. Acoustic information was processed with a Kay Computer Speech Laboratory. Differences exist in sound duration, pitch and loudness between lithic types, un-heat-treated and heat-treated stone, and stone of the same type but of high and of low quality. Heat treated samples conduct sound waves of longer duration than unheated samples, and heat-treated samples’ sounds were louder than un-heat-treated samples. An ancient knapper could use perceptible differences in sound produced by a nodule when tapped with a hammerstone to select or discard nodules or flakes of one lithic type over another based on anticipated predictability of flaking.