Anorthosite is one of the important type of rocks. If we have to define Anorthosite in general, Anorthosite is a granular igneous rock composed largely of labradorite or plagioclase. Anorthosite comes under Igneous Rocks. All Igneous Rocks have similar properties and formation process. Along with Anorthosite Definition, know more about the History of Anorthosite, Etymology of Anorthosite in next sections.