A hammer stone is made of a material such as limestone or quartzite, is often ovoid in shape (to better fit the human hand), and develops telltale battering marks on one or both ends. In archaeological recovery, hammer stone is often found in association with other stone tool artifacts, debitage and/or objects of the hammer such as ore. The modern use of hammer stone is mostly limited to flintknappers and others who wish to develop a better understanding of how stone tools were made.