What is metate stone?

Metate stones are hand-held grinding stones used for processing food items such as maize, beans, and nuts. They are made of either volcanic rock or sandstone and have a slightly concave surface, which is used for grinding. The metate stone is usually paired with a mano, a smaller, round stone used for grinding. The food items are placed on the metate stone, and the mano is used to grind them into a paste or powder. Metate stones were commonly used by Native Americans and Mesoamerican cultures and have a long history in traditional cooking practices.