Igneous rocks are formed from what?

Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface. Cooled and solidified magma can then form various types of igneous rocks. There are two main groups, intrusive or extrusive, depending upon where the molten rock solidifies.

Source: United States Geological Survey