The sand grains making up an arkose may range from fine to very coarse, but tend toward the coarser end of the scale.

Fossils are rare in arkose, due to the depositional processes that form it, although bedding is frequently visible.

Arkose is generally formed from the weathering of feldspar-rich igneous or metamorphic, most commonly granitic, rocks, which are primarily composed of quartz and feldspar (called 'grus' as a sand).

These sediments must be deposited rapidly and/or in a cold or arid environment such that the feldspar does not undergo significant chemical weathering and decomposition; therefore arkose is designated a texturally immature sedimentary rock.

The central Australian inselberg Uluru (Ayers Rock) is composed of late Neoproterozoic/Cambrian arkose, deposited in the Amadeus Basin.