ARKOSES, ARKOSIC SANDSTONE (EN: arkose, areose; DE: Arkosen; FR: arkosArkoseses; ES: arcosicas; RU: аркозы, аркозовый песчаник) are the coarse-grained rocks, which are consisting of quartz, feldspars, mica, and cementing (clayish, carbonatic) substances; they are the product of the destruction of granites and gneisses. They are characteristical for the cold climate (sometimes arid) of the flat plain regions; during the humid conditions, they form themselves at the conditions of the strongly dissected relief (rapid destruction) and poorly developed weathering crust. They are represented primarily with the sandstones and gritstones, usually with unsorted and angular grains. They are the raw material for the obtainment of the crushed gravel.