Classification of igneous rocks

Igneous rocks are rocks formed from molten magma. The material is made liquid by the heat inside the Earth’s mantle.
Igneous rock occurs in two ways.

  • Slow cooling:
    Igneous rock formed from magma that has become solid inside the earth is called intrusive igneous rock. Examples of intrusive igneous rock types are gabbro, diorite, and granite.
  • Fast cooling:
    Igneous rock formed from lava that has become solid outside of the Earth is called extrusive igneous rock. This can happen because of the eruption of a volcano. Some extrusive igneous rock types are basalt, andesite, rhyolite, tuff, obsidian, and pumice.

Igneous rock table