Magma (Plurals include: magmas and magmata) is molten rock that sometimes forms beneath the surface of the earth (or any other terrestrial planet) that often collects in a magma chamber inside a volcano. Magma may contain suspended crystals and gas bubbles. By definition, all igneous rock is formed from magma.

Hawaiian lava flow (lava is the extrusive equivalent of magma *Pahoehoe)

Magma is a complex high-temperature fluid substance. Temperatures of most magmas are in the range 700 °C to 1300 °C (or 1292 °F to 2372 °F), but very rare carbonatite melts may be as cool as 600 °C, and komatiite melts may have been as hot at 1600 °C. Most are silicate solutions.

Magma is capable of intrusion into adjacent rocks, extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock.

Environments of magma formation and compositions are commonly correlated. Environments include subduction zones, continental rift zones, mid-oceanic ridges, and hotspots, some of which are interpreted as mantle plumes. Environments are discussed in the entry on igneous rock. Magma compositions may evolve after formation by fractional crystallization, contamination, and magma mixing.

Contrary to some impressions,^[clarify] the bulk of the Earth's crust and mantle is not molten. Rather, the bulk of the Earth takes the form of a rheid, a form of solid that can move or deform under pressure. Magma, as liquid, preferentally forms in high temperature, low pressure environments within several kilometers of the Earth's surface.