 As the kimberlite magmas approach a depth of at least , the magma explodes violently through the Earth's crust, carrying fragments of rock that it has collected along the way and, in the right conditions, possibly diamonds, to the surface.The Eocene (ca.55–50 Ma) age diatremes of the Lac de Gras kimberlite field in the central Slave craton of the Northwest Territories support two world-class diamond mines, called Ekati and Diavik.