Magma is a material present in the earth's crust, at depths between 10-100 km. It is generated by local heating and melting of rocks. Magma upon cooling, solidifies and crystallizes into a mosaic of minerals. These minerals are known as igneous rocks. Volcanic eruptions can also produce igneous rocks. A volcano is created when magma is extruded onto the earth's surface. Magma which creates a volcano is known as extrusive igneous rocks. Magma which gets solidified below the surface of the earth is known as intrusive igneous rock. The minerals contained in igneous rocks are quartz, feldspar, muscovite, biotite and mafics. The most abundant igneous rocks are granite and basalt. Some other examples for igneous rocks are Rhyolite, andesite, dolerite, diorite, gabbro and porphyry.
