Kimberlite source of mined diamonds today. The consensus on kimberlites is that they are formed deep within the mantle. Formation occurs at depths between , potentially from anomalously enriched exotic mantle compositions, and they are erupted rapidly and violently, often with considerable carbon dioxideand other volatile components. It is this depth of melting and generation that makes kimberlites prone to hosting diamond xenocrysts. Despite its relative rarity, kimberlite has attracted attention because it serves as a carrier of diamonds and garnet peridotite mantle xenoliths to the Earth's surface. Its probable derivation from depths greater than any other igneous rock type, and
Volcanic rock grained matrix. Volcanic rocks often have a vesicular texture caused by voids left by volatiles trapped in the molten lava. Pumice is a highly vesicular rock produced in explosive volcanic eruptions. Most modern petrologists classify igneous rocks, including volcanic rocks, by their chemistry when dealing with their origin. The fact that different mineralogies and textures may be developed from the same initial magmas has led petrologists to rely heavily on chemistry to look at a volcanic rock's origin. The chemistry of volcanic rocks is dependent on two things: the initial composition of the primary magma and the subsequent differentiation. Differentiation