Sedimentary rock
Diatomite
A soft, siliceous rock that crumbles to a fine white powder, made of the amorphous silica (opal) frustules of diatoms in lake or marine sediments; dried material is typically 80–90% silica. Light and very porous. Commercial deposits are Tertiary and Quaternary.
Other sedimentary rocks
Conglomerate and breccia · Quartz arenite · Arkose · Lithic arenite · Wacke (greywacke) · Mudrocks: shale, mudstone, siltstone, claystone · Limestone · Chalk · Coquina · Oolite · Travertine and tufa · Dolostone · Chert · Radiolarite · Evaporites: rock salt and gypsum · Banded iron formation · Coal: peat to anthracite · Oil shale