hornfels rock

Is Hornfels Foliated Or Nonfoliated? Hornfels. Hornfels is another non-foliated metamorphic rock that normally forms during contact metamorphism of fine-grained rocks like mudstone or volcanic rocks. What rocks are Nonfoliated? Nonfoliated metamorphic rocks lack foliated texture because they often lack platy minerals such as micas. They commonly result from contact or regional metamorphism. Examples include