Sedimentary rock
Mudrocks: shale, mudstone, siltstone, claystone
At least 75% silt- and clay-sized grains (under 63 µm). Shale is finely laminated and splits into sheets; mudstone mixes silt and clay without shale's layering; siltstone is mostly silt; claystone is mostly clay.
More photos and thin sections
Other sedimentary rocks
Conglomerate and breccia · Quartz arenite · Arkose · Lithic arenite · Wacke (greywacke) · Limestone · Chalk · Coquina · Oolite · Travertine and tufa · Dolostone · Chert · Diatomite · Radiolarite · Evaporites: rock salt and gypsum · Banded iron formation · Coal: peat to anthracite · Oil shale