Cinders are melted volcanic rock that cooled and formed pebble-sized pieces when it was thrown out into the air. They are ejected from a single vent and accumulate around the vent when they fall back to earth. Bombs are melted volcanic rock that cooled and formed large pieces of rock when it was thrown out into the air before landing on the ground. Cinder cones are chiefly formed by Strombolian eruptions. They grow rapidly and soon reach their maximum size.
Cinder cones can occur alone or in small to large groups or fields.
Most have a bowl-shaped crater at the summit. The longer the eruption, the higher the cone. They rarely exceed 250 meters in height and 500 meters in diameter, although some may rise to as high as 650 meters or more. If gas pressure drops, the final stage cinder cone construction may be a lava flow that breaks through the base of the cone. If a lot of water in the environment has access to the molten magma, their interaction may result in a maar volcano rather than a cinder cone.