Trondhjemite is one of the important type of rocks. If we have to define Trondhjemite in general, Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites are sometimes known as plagiogranites.. Trondhjemite comes under Igneous Rocks. All Igneous Rocks have similar properties and formation process. Along with Trondhjemite Definition, know more about the History of Trondhjemite, Etymology of Trondhjemite in next sections.