Curling stones are heavy, polished granite rocks used in the sport of curling. Each stone weighs approximately 44 pounds and has a diameter of about 36 inches. They are designed with a slight concave bottom, allowing them to glide smoothly over the ice surface when thrown. The stones are equipped with a handle on top, which players use to deliver them down the curling sheet. Players can also impart a spin to the stone, affecting its trajectory and how it interacts with other stones. The unique properties of the granite and the careful design contribute to the game's strategic elements.