Kimberlite is a type of igneous rock best known for sometimes containing diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5 carat diamond in 1871 spawned a diamond rush, eventually creating the Big Hole. Kimberlite occurs in the Earth's crust in vertical structures known as kimberlite pipes. Kimberlite pipes are the most important source of mined diamonds today. The general consensus reached on kimberlites is that they're formed deep within the man… (More on Kimberlite)