Igneous rocks are one of the three main classifications of rocks, and they are formed both above and below ground. Learn about the intrusive and coarse-grained nature of igneous rocks with help from a lab manager and research scientist in this free video on identifying rocks.
About the Author
Jane Stammer is a lab manager and research scientist in the Advanced Mineralogy Research Center at the Colorado School Of Mines. Stammer has a master's degree in geology.