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 Male Rock Vocal Performance Originally called the Grammy Award for Best Rock Vocal Performance, Male, the award was first presented to Bob Dylan in 1980. Beginning with the 1995 ceremony, the name of the award was changed to Best Male Rock Vocal Performance. However, in 1988, 1992, 1994, and since 2005, this category was combined with the Grammy Award for Best Female Rock Vocal Performance and presented in a genderless category known as Best Rock Vocal Performance, Solo. The solo category was later renamed to Best Solo Rock Vocal Performance beginning in 2005. This fusion has been criticized, especially when females are not nominated