According to the U.S. Geological Survey, a cinder cone is the simplest type of volcano, built up out of lava deposits left by a single magma vent. When the vent blows lava into the air, fragments cool and solidify, falling to earth around the vent. Over time, these deposits build up into a cone-shaped hill.
Cinder cones can build up as part of other volcanoes, forming around magma vents on shield volcanoes or calderas. These tend to be relatively small volcanoes, rarely reaching more than 1,000 feet in height. Cinder cones tend to be less stable than other volcano types, due to the small fragments that make up the body of the volcano. This leaves them prone to vent collapses, which can cause pressure to build up beneath the cone and trigger an explosive eruption. Under some circumstances, these explosive eruptions can completely destroy a cinder cone, blowing the solidified lava fragments away from the vent.
One famous example of a cinder cone volcano is Paricutin, a volcano that formed around a vent in a corn field in Mexico. The vent opened in 1943, and the cone quickly built up around it, eventually reaching a height of nearly 1,400 feet.