Phonolite is one of the important type of rocks. If we have to define Phonolite in general, Phonolite is an uncommon extrusive igneous rock volcanic rock of intermediate chemical composition between felsic and mafic. Phonolite comes under Igneous Rocks. All Igneous Rocks have similar properties and formation process. Along with Phonolite Definition, know more about the History of Phonolite, Etymology of Phonolite in next sections.