A sedimentary rock composed of particle-shaped material (larger than 1/16 mm but smaller than 2 mm). In terms of abundance, sandstone is second only to clay rock. Sandstones are formed from sand stored in rivers , delta areas , shallow seas , deep seas , deserts or any other sedimentary environment. Sandstone is one of the important rocks as a petroleum reservoir. In fact , half of the world's vast petroleum deposits exist in sandstone deposits. All gas basins in the gas fields of Bangladesh are composed of sandstone layers. These gas reservoirs are considered to be the best of the best because of the high porosity and penetration of the rock. In addition to forming a gas reservoir, sandstone is a common rock that forms the geology of Bangladesh. Newer geological units , such as the Dupi Tila Layers and the Tipam Layers, are mainly composed of sandstones that form low-lying hills in the hilly areas of eastern Bangladesh. The geological unit of the Surma rock group within them is also composed of almost equal-grained sandstone (gas reservoir) and stratification of clay rock. Sandstone is often used as a bulk in large-scale construction .