Hornfels

Hornfels is a type of metamorphic rock that forms when existing rocks are subjected to high temperatures, often due to contact with molten magma or intense heat from nearby igneous activity. Unlike rocks that change shape gradually, hornfels forms quickly with a fine-grained texture, resulting from mineral changes caused by heat. It can originate from various original rocks, such as shale, sandstone, or volcanic ash. Hornfels is typically hard, dense, and non-foliated (lacking layered structure), making it useful in construction and as a raw material for cutting tools.