Grinding tools are very common at Nok sites. They are rarely preserved in one piece, but can still illustrate the different shapes and sizes of tools used throughout the Nok Culture. Grinding stones were made of quartzite, granitic, or metamorphic rock. At the site of Ungwar Kura, grinding stones seem to have been placed in a certain order, and at the site of Ido huge grinding slabs were arranged in an upright position with pots and stone beads next to them. This context is assumed to have been ritual in some way. Most of the grinders are merely hand-sized. Throughout Nok sites, there is an abundance of grinding slabs but there seems to be a low number of hand stones. It is possible that members of the Nok Culture used these grinders until they reached a certain state of wear, and then repurposed them as pestles.