In archaeology, a hammerstone is a hard cobble used to strike lithic flakes off a lump of tool stone during the process of lithic reduction. Often, a hammerstone is made of a material such as limestone or quartzite, is ovoid in shape (to better fit the human hand) and develops telltale battering on the ends. This technology was of major importance to prehistoric cultures who had yet to learn to work metal; today, however, the use of hammerstones is mostly limited to flintknappers and others who wish to develop a better understanding of how stone tools were made.