What is Magma?
Silicon and Oxygen in Magma
Magma is molten rock beneath Earth's surface. Once expelled from the vent of a volcano it becomes known as lava.
Magma is generally made up of eight chemical elements. The most important are oxygen, silicon, aluminium and iron.
Intrusive igneous rocks are formed when magma cools very slowly over millions of years. One of the best examples is granite.