Appinite is one of the important type of rocks. If we have to define Appinite in general, Appinite is an igneous rock in which the crystals are so fine grained that individual minerals cannot be easily distinguished. Appinite comes under Igneous Rocks. All Igneous Rocks have similar properties and formation process. Along with Appinite Definition, know more about the History of Appinite, Etymology of Appinite in next sections.