Magma is the dough of the Ring of Fire cookie! Magma is liquid rock before it reaches the surface (magma which reaches the surface is called lava). Magma is stored within several magma chambers in the crust, besides coming from the mantle. When a plate subducts, large pieces of plate break off and are sent down. These can melt and create magma as well. Magma is a silicate solution and is an ancestor to igneous rock. Magma tempature ranges from 650 degrees celsius to 1200 degrees celsius. Magma is usually under high pressure. When it breaks the surface however, it melts. Magma which reaches the surface is also called pyroclastic ejecta. Magma is formed by a sudden decrease in pressure. Magma's geothermal gradient is about 25 degrees Celsius/km. A geothrmal gradient is the rate of increase in temperature per unit depth in the Earth. Magma can also be formed by adding volatiles (water and gasses). Magma can only be formed under certain conditions in the athenosphere (middle mantle). Preexisting magma can create more magma by melting more rocks on it's way up. Magma rises because a melt is lighter than the actual rock. Magma also propels itself through the lithosphere (crust and upper mantle) because of it's buoyancy of the lesser density. Magma contains mineral crystals and dissolved gasses apart from the melted rock. The most important chemical compound is silica (Si02). The amount of silica determines it's viscosity (resistance to flow). Please note that glass is a liquid with extremely high viscosity. More silica means more viscosity. However, hotter tempatures mean less viscosity. There are 2 magma types, basaltic and granitic. Basaltic contains only 50% silica. Granitic however, can contain as much as 70% silica. Magma serves as the main fuel for volcanoes and plate movements in the Ring of Fire. My prediction is that magma will always be around the corner to haunt you!