Terms designating composition and physical characteristics

Detrital rocks

Rudites (coarse)

conglomerates (rounded clasts)

breccias (angular clasts)

basal, or transgression

fanglomerates (in alluvial fans)

tillites (glacially transported)

Arenites (medium-grained)

sandstone

arkose (feldspar-rich)

graywacke (sandstone with mud matrix)

quartzite (orthoquartzite)

Lutites (fine-grained)

siltstone

shale

mudstone or claystone

argillite

loess (transported and deposited by wind)

Nondetrital rocks

Precipitates

chemical precipitates (rocks formed by precipitation from seawater or fresh water)

evaporites (products of evaporation from saline brines)

duricrust rocks (hardened surface or mean-surface layer of any composition)

Organic

zoogenic (made up of hard parts of animals; e.g., crinoidal limestone)

phytogenic (made up of plant remains; e.g., algal limestone)