Sedimentary rocks formed from the consolidation of sand, with sand-sized grains (0.06252 mm/0.00250.08 in) in a matrix or cement. Their principal component is quartz. Sandstones are commonly permeable and porous, and may form freshwater aquifers. They are mainly used as building materials.
Sandstones are classified according to the matrix or cement material (whether derived from clay or silt).
Black recalls the country's tragic past. White reflects the Georgians' hopes for the future. Dark red is the national colour and is said to represent happiness. Effective date: 14 November 1990.