Question: is mudstone a metamorphic rock?
Answer: Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.063 millimetres (0.0025 in) with individual grains too small to be distinguished without a microscope. ... Mudstone — hardened mud; a mix of silt and clay sized particles.