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 Album Grammy Award for Best Rock Album The Grammy Award for Best Rock Album is an award presented at the Grammy Awards, a ceremony that was established in 1958 and originally called the Gramophone Awards, to recording artists for quality albums in the rock music genre. Honors in several categories are presented at the ceremony annually by the National Academy of Recording Arts and Sciences of the United States to "honor artistic achievement, technical proficiency and overall excellence in the recording industry, without regard to album sales or chart position". The award for Best Rock Album was first presented to the