#sandstone
- Arkose — A coarse-grained detrital sedimentary rock, similar to sandstone, structurally formed by the disintegration of granite or other plutonic rocks and composed of a high percentage of feldspar (over 25%) alongside quartz and mica. Geologically, the presence of arkose in a terrestrial stratum indicates rapid mechanical weathering and short-distance transport in an arid or semi-arid climate, where chemical alteration was minimized.
- Arenarie — An extremely rare term or obsolete variant previously used in sedimentology to designate a consolidated detrital sedimentary rock formed from cemented sand grains, currently known as sandstone. Its structural meaning stems from the Latin root relating to sand, indicating the coarse granulometric composition of the rock.
- Arenite — A clastic or detrital sedimentary rock composed of medium-grained mineral particles, with diameters structurally ranging from 0.0625 to 2 millimeters (sand-sized particles), cemented within a fine matrix. Unlike wacke, an arenite contains less than 15% interstitial clay matrix, being strictly classified based on grain composition into quartz, feldspathic, or lithic arenite.