Sedimentary rock
Dolostone
Carbonate rock made of the mineral dolomite, CaMg(CO₃)₂, formed by dolomitization of limestone by magnesium-rich fluids. It reacts only feebly with dilute HCl.
More photos and thin sections
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 · Chert · Diatomite · Radiolarite · Evaporites: rock salt and gypsum · Banded iron formation · Coal: peat to anthracite · Oil shale
Sources
Panchuk, Physical Geology 9.2: Chemical and Biochemical Sedimentary Rocks · Wikipedia: Limestone