Hornfels is one of the important type of rocks. If we have to define Hornfels in general, Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock. Hornfels comes under Metamorphic Rocks. All Metamorphic Rocks have similar properties and formation process. Along with Hornfels Definition, know more about the History of Hornfels, Etymology of Hornfels in next sections.