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What Type of Sedimentary Rock Is Formed From Compressed Sand?

Rocks formed from compressed particles of sand, shells and pebbles are sedimentary rocks. The material rocks are composed of determines the type of sedimentary rock, and rocks formed from layers of compressed sand are sandstones. Sandstone is usually white, gray, brown, orange or red in color; iron oxide and manganese impurities cause red, brown, orange, purple or green coloration. They feel gritty and many crumble easily under pressure. Sandstones have porous areas between each grain of sand that can fill with substances such as oil, bitumen and natural gas.

Sandstone Composition
- According to the University of Kentucky's Geological Survey, sandstone is composed of mineral grains such as quartz or feldspar, which are the most common minerals in the earth's crust. Sandstone forms when ground water flows through the pores of layers of compressed sand, leaving substances such as silica, iron oxide, or calcium carbonate that cement the grains together. The cementing substance determines the color, texture and durability of the stone. Sandstone held together with silica is hard and durable, while stone cemented with gypsum or clay is much softer and erodes easily. Calcite-cemented sandstone easily dissolves in acid.
Sandstone Types
- The three major types of sandstone are quartz, arkose and lithic sandstone. Quartz sandstone is made up mainly of quartz particles; arkose is made primarily of feldspar; and lithic is made from rock fragment grains. Most of the quartz sandstone is white or gray in color, though some is red or orange. Arkose is usually reddish-brown, pink or gray. Lithic sandstone is darker and smoother than other types. Rock asphalt is a medium- to coarse-grained sandstone with bitumen filling spaces between the grains of sand. It is brown to black and is very sticky when it's soaked.
Sandstone Uses
- Sandstones are very resistant to erosion, causing them to be used in a number of industries. Tightly compressed sandstone that is firmly cemented together is used as a building stone. White sandstones and those formed with high amounts of quartz are used to make window glass, light bulbs and glass containers. Rock asphalt is used for roofing, waterproofing and factory flooring, as well as for surfaces for driveways, streets and highways. Porous sandstone is used as reservoirs for oil and natural gas.
Sandstone Locations
- Sandstone forms in areas such as beaches, sand dunes and the ocean floor. Quartz sandstone is common in North America and Australia where it forms arches, canyons, bluffs, cliffs, ridges and waterfalls. Arkose sandstone is typically found in basins and valleys. Lithic sandstone is found in arid or temperate climates where erosion occurs quickly.

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