Sandstein

Sandstein (sandstone) is a sedimentary rock formed from sand-sized grains that have been compacted and cemented together. The dominant mineral is quartz; feldspar and lithic fragments occur in arkose and other varieties. The grains are bound by cement, typically silica, calcite, or iron oxides, giving color from white to red-brown.

Sandstone forms by lithification of sands deposited in rivers, beaches, deserts, deltas, or continental shelves. Over burial, compaction reduces pore space and mineral-rich fluids precipitate cement that binds the grains.

Quartz sandstone is mainly quartz; arkose contains feldspar; lithic sandstone has abundant rock fragments; greywacke is poorly sorted with a clay-rich matrix. Sedimentary structures such as cross-bedding and ripple marks may be preserved.

Sandstone occurs worldwide and has long been used as a building material and for decorative work. Its durability and ease of carving have made it important in architecture and sculpture, especially in regions with abundant high-quality stone.

In central Europe the Elbe Sandstone (Elbsandstein) region along the Elbe River in Saxony and Bohemia is renowned for fine, workable sandstone used in historic constructions. Color variations reflect cement and impurities; porosity and permeability depend on grain size and cement. Weathering can produce a distinctive rind on exposed surfaces.