Diorite is one of the important type of rocks. If we have to define Diorite in general, Diorite is a grey to dark-grey intermediate intrusive igneous rock composed principally of plagioclase feldspar,biotite, hornblende, and pyroxene. Diorite comes under Igneous Rocks. All Igneous Rocks have similar properties and formation process. Along with Diorite Definition, know more about the History of Diorite, Etymology of Diorite in next sections.