Eisco Hornfels Specimen (Metamorphic Rock), Approx. 1″ (3cm)

Hornfels forms in the narrow band between an igneous intrusion and the surrounding rock. As an intrusion propagates through the crust, the magma scorches and heats the crustal rock around it. This heat chemically alters the crust, forming a baked contact containing hornfels. This sample is good for metamorphic rock classification and identification, and is a great example of heat alteration.