Kimberlite
Kimberlite occurs in the Earth's crust in vertical structures known as "pipes" as well as igneous dykes and sills. Kimberlite pipes are the most important source of mined diamonds today. Kimberlites  form deep with the Earth's mantle. Formation occurs at depths between  Kimberlite material is erupted rapidly and violently, often with considerable carbon dioxide and other volatile components.