Quern-stone

A quern-stone is a stone tool used for hand grinding materials, especially grain, and was worked in pairs, with a stationary lower saddle quern and a mobile upper stone called a muller moved back and forth across it. Later rotary querns replaced this motion with rotation around a central hole called the eye, turned by a handle set into the upper stone, and the tool was first used in the Neolithic era to grind cereals into flour. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/