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 Instrumental Performance to Paul McCartney and the band Wings for "Rockestra Theme". From 1986 to 1989, the category was known as Best Rock Instrumental Performance (Orchestra, Group or Soloist). According to the category description guide for the 52nd Grammy Awards, the award is presented to artists "for newly recorded rock, hard rock or metal instrumental performances". As of 2011, Jeff Beck holds the records for the most wins, with six. Sting has received three awards, twice as a member of The Police -- although he had no part in the band's "Behind My Camel", the 1982 award winner which he did not