What are some common uses for igneous rocks?
Extrusive igneous rocks form when magma hardens above the earth's surface. Examples of these include pumice and basalt. Pumice is used in toothpaste and cosmetic products, while basalt is used in the construction of statues and buildings.
Intrusive igneous rocks form when magma hardens below the earth's surface. Granite is an example. Granite is used in countertops, statues and tombstones because of its durability. Gabbro is another intrusive igneous rock which contains profitable amounts of gold and silver.