Rock salt (halite) (chemical)

brittle; macroscopic crystals; tastes salty

Fossiliferous limestone (bioclastic)

small shell fragments; fizzes in HCl

Rock gypsum (chemical)

scratches with fingernail

Quartz sandstone (siliciclastic)

sandy texture; predominantly quartz

Arkose sandstone (siliciclastic)

sandy texture; predominantly feldspar

Shale (siliciclastic)

fine texture; layered

Coquina limestone (bioclastic)

gravel-sized shell and coral fragments; fizzes in HCl

Ironstone (chemical)

dark, dense; microcrystalline or amorphous

Chalk limestone (bioclastic)

fine grained; fizzes in HCl

Breccia (siliciclastic)

angular clasts in finer matrix

Oolitic limestone (chemical)

composed of small spherical grains fizzes in HCl

Mudstone or siltstone (siliciclastic)

fine grained mud

Conglomerate (siliciclastic)

rounded clasts in fine matrix

Graywacke sandstone (siliciclastic)

mixture of sand and mud

Bituminous coal (bioclastic)

black; brittle; not dense

Micrite limestone (bioclastic)

microcrystalline; conchoidal fracture; fizzes in HCl

Dolostone (chemical)

light colored; powder fizzes in HCl

Chert (chemical)

microcrystalline; conchoidal fracture; scratches glass