Magma is a
liquid solution or
melt that generally contains suspended
crystals and dissolved
volatiles.
Melts are comprised of silicates, carbonates or sulphides: silicate melts are the most common type of magma. The presence of silica is also directly proportional to the viscosity of the magma: the more silica, the more viscous the magma becomes.
Magma is created by a partial melting of the Earth's crust or mantle and is the raw material for all igneous processes. It may rise to the surface through volcanic fissures and be extruded as lava; if it solidifies underground it forms intrusive igneous rock.
Magma is also very, very, very, very hot.