Volcanic pipe Volcanic pipe Volcanic pipes are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of "diatreme". Volcanic pipes are composed of a deep, narrow cone of solidified magma (described as "carrot-shaped"), and are usually largely composed of one of two characteristic rock types — kimberlite or lamproite. These rocks reflect the composition of the volcanoes' deep magma sources, where the Earth is rich in magnesium. Volcanic pipes are relatively rare. They are well known as the primary source of diamonds, and are mined for this purpose. Volcanic pipes form as
Grammy Award for Best Rock Performance Grammy Award for Best Rock Performance The Grammy Award for Best Rock Performance is an award presented at the Grammy Awards, a ceremony that was established in 1958 and originally called the Gramophone Awards. According to the 54th Grammy Awards description guide it is designed for solo, duo/groups or collaborative (vocal or instrumental) rock recordings and is limited to singles or tracks only. This award combines the previous categories for Best Solo Rock Vocal Performance, Best Rock Performance by a Duo or Group with Vocal and Best Rock Instrumental Performance. The restructuring of these categories was a result of the