The main difference between a mudstone and shale is what?

Answer 1

Shale - a sedimentary rock formed from clay or mud by considerable pressure. splits easy into thin laminations along its bedding planes and shrinks when dried out cracking to form pieces that often curl slightly to resemble tiles. when moistened it has an earthy smell

Mudstone - a fine textured sedimentary rock similar to shale but is compact and is not, like shale, arranged in bedding planes

Answer 2

The main difference between mudstone and shale is the size of the particles they are composed of. Shale has very fine particles, which give it a layered appearance and the ability to split into thin sheets. Mudstone, on the other hand, has slightly larger particles that are typically too small to see with the naked eye, giving it a more massive and blocky structure.