kimberlite

noun

1. Petrology. a variety of micaceous peridotite, low in silica content and high in magnesium content, in which diamonds are formed.

noun

1. an intrusive igneous rock generated at great depth in the earth’s mantle and consisting largely of olivine and phlogopite. It often contains diamonds

1. A type of peridotite consisting of a fine-grained matrix of calcite and olivine and containing phenocrysts of olivine, garnet, and sometimes diamonds. Kimberlites are found in long, vertical volcanic pipes, especially in South Africa.