Pumice is an example of extrusive igneous rock. The word extrusive means that the magma was forced onto the earth's surface and cooled in a matter of hours. Granite is an example of intrusive ...

We’re at Rocky Mountain School of Expeditionary Learning for our 9NEWS Cool School of the month learning about intrusive and extrusive rocks. Trump emergency declaration cites eye-popping number ...

are formed by magma from the molten interior of the Earth. If magma erupts on the surface as lava, it will form extrusive rock, e.g. basalt. These rocks are formed when magma solidifies.

Igneous rocks contain randomly arranged interlocking crystals. The size of the crystals depends on how quickly the molten magma solidifies and can form extrusive igneous rocks or intrusive igneous ...