Sandstone is a sedimentary rock formed from cemented sand-sized clasts. The cement that binds the clasts can vary from clay minerals to calcite, silica or iron oxides. Sandstone can be further divided according to:
Clast size - fine (0.06-0.2mm), medium (0.2-0.6mm), coarse (0.6-2mm);
Sorting - a sandstone comprising a mixture of clast sizes is poorly sorted, while one comprising mostly clasts of the same size is well sorted; a sandstone containing very little silt and / or clay is termed arenaceous; a sandstone containing a significant amount of silt and / or clay is termed argillaceous or a "wacke" (see greywacke for more information);
Mineral content - a sandstone consisting of more than 25% feldspar clasts is termed arkose; a sandstone consisting of more than 90% quartz clasts is called quartzose