A medium- to coarse-grained rock that is pinkish to gray in color. Although predominantly made up of quartz, feldspar can contribute as much as a third of the rock. Constituents are usually well-sorted. Together with mica flakes, they are cemented in a calcitic or ferruginous cement.

TEXTURE The grains in this rock are angular and usually well-sorted.

ORIGIN Forms in marine and freshwater environments and continental deposits. Arkose is said to be an immature rock because of its high feldspar content.
The sediment that forms this rock is deposited rapidly or in an arid environment preventing the feldspar from decomposing. The effect of a long process of chemical weathering, erosion, and deposition would be to alter and decompose the feldspar. Most arkoses are derived from granite disintegration.

Grain size: Medium

Classification: Detrital

Fossils: Rare

Grain shape: Angular