Igneous rocks close igneous rockIgneous ... If magma erupts on the surface as lava, it will form extrusive rock, e.g. basalt. These rocks are formed when magma solidifies. As the magma cools ...

producing extrusive or volcanic igneous rocks like basalt. As magma cools, the minerals within it begin to crystallize and interlock to create solid rock. The rate of cooling affects the size of ...