Examines the question of the influence of abrasive particles on the development of usewear on stone tools. It is argued that grit inclusions may have been a common element of prehistoric tool using conditions, hence the need for archaeological experiments which consider this variable. A series of experiments are described where end-scrapers were used on bone and hide surfaces both with and without a grit inclusion. The resulting wear patterns are discussed and illustrated. It is concluded that the addition of grit to the worked surface causes a dramatic and demonstrable change in use-wear development. -- AATA