Updated October 20, 2017
By Jane Stammer
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.