<Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (June 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (June 2015) (Learn how and when to remove this template message) </Td> </Tr> <P> A cinder cone or scoria cone is a steep conical hill of loose pyroclastic fragments, such as either volcanic clinkers, cinders, volcanic ash, or scoria that has been built around a volcanic vent . They consist of loose pyroclastic debris formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent . As the gas - charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around the vent to form a cone that often is symmetrical; with slopes between 30--40 °; and a nearly circular ground plan . Most cinder cones have a bowl - shaped crater at the summit . </P> <P> The rock fragments, often called cinders or scoria, are glassy and contain numerous gas bubbles "frozen" into place as magma exploded into the air and then cooled quickly . Cinder cones range in size from tens to hundreds of meters tall . Cinder cones are made of pyroclastic material . Many cinder cones have a bowl - shaped crater at the summit . During the waning stage of a cinder - cone eruption, the magma has lost most of its gas content . This gas - depleted magma does not fountain but oozes quietly into the crater or beneath the base of the cone as lava . Lava rarely issues from the top (except as a fountain) because the loose, uncemented cinders are too weak to support the pressure exerted by molten rock as it rises toward the surface through the central vent . Because it contains so few gas bubbles, the molten lava is denser than the bubble - rich cinders . Thus, it often burrows out along the bottom of the cinder cone, lifting the less dense cinders like a cork on water, and advances outward, creating a lava flow around the cone's base . When the eruption ends, a symmetrical cone of cinders sits at the center of a surrounding pad of lava . If the crater is fully breached, the remaining walls form an amphitheatre or horseshoe shape around the vent . </P>

What type of lava is associated with cinder cones