
[Middle English, from Old English.]
For more information on sand, visit Britannica.com.
Background
Sand is a loose, fragmented, naturally-occurring material consisting of very small particles of decomposed rocks, corals, or shells. Sand is used to provide bulk, strength, and other properties to construction materials like asphalt and concrete. It is also used as a decorative material in landscaping. Specific types of sand are used in the manufacture of glass and as a molding material for metal casting. Other sand is used as an abrasive in sandblasting and to make sandpaper.
Sand was used as early as 6000 B.C. to grind and polish stones to make sharpened tools and other objects. The stones were rubbed on a piece of wetted sandstone to hone the cutting edge. In some cases, loose sand was scattered on a flat rock, and objects were rubbed against the sandy surface to smooth them. The first beads with a glass glaze appeared in Egypt in about 3,500-3,000 B.C. The glass was made by melting sand, although naturally-occurring glass formed by volcanic activity was probably known long before that time.
In the United States, sand was used to produce glass as early as 1607 with the founding of the short-lived Jamestown colony in Virginia. The first sustained glass-making venture was formed in 1739 in Wistarburgh, New Jersey, by Caspar Wistar. The production of sand for construction purposes grew significantly with the push for paved roads during World War I and through the 1920s. The housing boom of the late 1940s and early 1950s, coupled with the increased use of concrete for building construction, provided another boost in production.
Today, the processing of sand is a multi-billion dollar business with operations ranging from very small plants supplying sand and gravel to a few local building contractors to very large, highly automated plants supplying hundreds of truckloads of sand per day to a wide variety of customers over a large area.
Raw Materials
The most common sand is composed of particles of quartz and feldspar. Quartz sand particles are colorless or slightly pink, while feldspar sand has a pink or amber color. Black sands, such as those found in Hawaii, are composed of particles of obsidian formed by volcanic activity. Other black sands include materials such as magnetite and homblende. Coral sands are white or gray, and sands composed of broken shell fragments are usually light brown. The white sands on the Gulf of Mexico are made of smooth particles of limestone known as oolite, derived from the Greek word meaning egg stone. The white sands of White Sands, New Mexico, are made of gypsum crystals. Ordinarily, gypsum is dissolved by rain water, but the area around White Sands is so arid that the crystals survive to form undulating dunes.
Quartz sands, which are high in silica content, are used to make glass. When quartz sands are crushed they produce particles with sharp, angular edges that are sometimes used to make sandpaper for smoothing wood. Some quartz sand is found in the form of sandstone. Sandstone is a sedimentary, rock-like material formed under pressure and composed of sand particles held together by a cementing material such as calcium carbonate. A few sandstones are composed of almost pure quartz particles and are the source of the silicon used to make semiconductor silicon chips for microprocessors.
Molding sands, or foundry sands, are used for metal casting. They are composed of about 80%-92% silica, up to 15% alumina, and2% iron oxide. The alumina content gives the molding sand the proper binding properties required to hold the shape of the mold cavity.
Sand that is scooped up from the bank of a river and is not washed or sorted in any way is known as bank-run sand. It is used in general construction and landscaping.
The definition of the size of sand particles varies, but in general sand contains particles measuring about 0.0025-0.08 in (0.063-2.0 mm) in diameter. Particles smaller than this are classified as silt. Larger particles are either granules or gravel, depending on their size. In the construction business, all aggregate materials with particles smaller than 0.25 in (6.4 mm) are classified as fine aggregates. This includes sand. Materials with particles from 0.25 in (6.4 mm) up to about 6.0 in (15.2 cm) are classified as coarse aggregates.
Sand has a density of 2,600-3,100 lb per cubic yard (1,538-1,842 kg per cubic meter). The trapped water content between the sand particles can cause the density to vary substantially.
The Manufacturing
Process
The preparation of sand consists of five basic processes: natural decomposition, extraction, sorting, washing, and in some cases crushing. The first process, natural decomposition, usually takes millions of years. The other processes take considerably less time.
The processing plant is located in the immediate vicinity of the natural deposit of material to minimize the costs of transportation. If the plant is located next to a sand dune or beach, the plant may process only sand. If it is located next to a riverbed, it will usually process both sand and gravel because the two materials are often intermixed. Most plants are stationary and may operate in the same location for decades. Some plants are mobile and can be broken into separate components to be towed to the quarry site. Mobile plants are used for remote construction projects, where there are not any stationary plants nearby.
The capacity of the processing plant is measured in tons per hour output of finished product. Stationary plants can produce several thousand tons per hour. Mobile plants are smaller and their output is usually in the range of 50-500 tons (50.8-508 metric tons) per hour.
In many locations, an asphalt production plant or a ready mixed concrete plant operates on the same site as the sand and gravel plant. In those cases, much of the sand and gravel output is conveyed directly into stockpiles for the asphalt and concrete plants.
The following steps are commonly used to process sand and gravel for construction purposes.
Natural decomposition
Extraction
Sorting
Washing
Crushing
Quality Control
Most large aggregate processing plants use a computer to control the flow of materials. The feed rate of incoming material, the vibration rate of the sorting screens, and the flow rate of the water through the sand classifying tank all determine the proportions of the finished products and must be monitored and controlled. Many specifications for asphalt and concrete mixes require a certain distribution of aggregate sizes and shapes, and the aggregate producer must ensure that the sand and gravel meets those specifications.
The Future
The production of sand and gravel in many areas has come under increasingly stringent restrictions. The United States Army Corps of Engineers, operating under the Federal Clean Water Act, has required permits for sand extraction from rivers, streams, and other waterways. The cost of the special studies required to obtain these permits is often too expensive to allow smaller companies to continue operation. In other cases, residential development in the vicinity of existing aggregate processing plants has led to restrictions regarding noise, dust, and truck traffic. The overall result of these restrictions in certain areas is that sand and gravel used for construction will have to be transported from outside the area at a significantly increased cost in the future.
Where to Learn More
Books
Brady, George S. and Henry R. Clauser. Materials Handbook, 12th Edition. McGraw-Hill, 1986.
Hornbostel, Caleb. Construction Materials, 2nd Edition. John Wiley and Sons, Inc., 1991.
Siever, Raymond. Sand. W.H. Freeman and Company, 1988.
Periodicals
Grover, Jennifer E., Bob Drake, and Steven Prokopy. "100 Years of Rock Products, History of an Industry: 1896-1996." Rock Products, July 1996, pp. 29+.
Mack, Walter N. and Elizabeth A. Leistikow. "Sands of the World." Scientific American, August 1996, pp. 62-67.
Miller, Russell V. "Changes in Construction Aggregate Availability in Major Urban Areas of California Between the Early 1980s and the Early 1990s." California Geology, January/February 1997, pp. 3-17.
[Article by: Chris Cavette]
Unconsolidated granular material consisting of mineral, rock, or biological fragments between 63 micrometers and 2 mm in diameter. Finer material is referred to as silt and clay; coarser material is known as gravel. Sand is usually produced primarily by the chemical or mechanical breakdown of older source rocks, but may also be formed by the direct chemical precipitation of mineral grains or by biological processes. Accumulations of sand result from hydrodynamic sorting of sediment during transport and deposition. See also Clay minerals; Depositional systems and environments; Gravel; Mineral; Rock; Sedimentary rocks.
Most sand originates from the chemical and mechanical breakdown, or weathering, of bedrock. Since chemical weathering is most efficient in soils, most sand grains originate within soils. Rocks may also be broken into sand-size fragments by mechanical processes, including diurnal temperature changes, freeze-thaw cycles, wedging by salt crystals or plant roots, and ice gouging beneath glaciers. See also Weathering processes.
Because sand is largely a residual product left behind by incomplete chemical and mechanical weathering, it is usually enriched in minerals that are resistant to these processes. Quartz not only is extremely resistant to chemical and mechanical weathering but is also one of the most abundant minerals in the Earth's crust. Many sands dominantly consist of quartz. Other common constituents include feldspar, and fragments of igneous or metamorphic rock. Direct chemical precipitation or hydrodynamic processes can result in sand that consists almost entirely of calcite, glauconite, or dense dark-colored minerals such as magnetite and ilmenite. See also Feldspar; Quartz.
Although sand and gravel has one of the lowest average per ton values of all mineral commodities, the vast demand makes it among the most economically important of all mineral resources. Sand and gravel is used primarily for construction purposes, mostly as concrete aggregate. Pure quartz sand is used in the production of glass, and some sand is enriched in rare commodities such as ilmenite (a source of titanium) and in gold. See also Concrete.
geology A particle size, of maximum diameter 2 mm (0.787~ in), ranging to about a sixth of that depending on the scheme employed.
Particles of rock with diameters ranging from 0.06 mm to 2.00 mm. Most sands are formed of the mineral, quartz. Sandy soils are loose, non-plastic, and permeable, and have little capacity to hold water.
A custom reported in several locations but surviving only at Knutsford, Cheshire, is the decoration of pavements with coloured sand on special occasions such as May Day and for local weddings. At Knutsford, the sand is dispensed through a funnel, and it is said that it is better when it rains because the colour thus lives on for a while in the paving stones. Henderson (1879: 40-1) also mentions sand strewing for weddings in 19th-century Newcastle.
Bibliography
The full bibliography list is available here.
1. Granular material which passes through a 9.51-μ (⅜-in.) sieve, almost entirely passes through a 4.76-mm (No. 4) sieve, and is predominantly retained on a 74-μ (No. 200) sieve; results from natural disintegration and abrasion of rock or processing of completely friable sandstone.
2. That portion of an aggregate passing through a 4.76-mm (No. 4) sieve and predominantly retained on a 74-μ (No. 200) sieve. Also see sieve number.
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Fine to medium-sized particles of between 2mm and 0.06mm across forming constituent components of natural and anthropogenic sediments and deposits.
The worn grains of rock, the largest of the three minerals that form the basis of soil. The other two are silt and clay.
All love that has not friendship for its base, Is like a mansion built upon the sand.
— Ella Wilcox (1850-1919), American poet and journalist.
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| san fairy ann(e), sambo, sambie | |
| sand-groper, sandbag, sanger |
1. material occurring in fine, gritty particles loose in the body.
2. geological sand is ingested by animals, especially horses, grazing on very sandy soil. The animals may take in large amounts and this accumulates in the large sacs of the alimentary tract, the reticulum of the cow and the cecum and colon in horses. Sand or dust storms, or volcanic dust fallout may produce a similar, acute situation.

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This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2008) |
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz.
The second most common form of sand is calcium carbonate, for example aragonite, which has mostly been created, over the past half billion years, by various forms of life like coral and shellfish. It is, for example, the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years, like the Caribbean.
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In terms of particle size as used by geologists, sand particles range in diameter from 0.0625 mm (or ⅟16 mm) to 2 mm. An individual particle in this range size is termed a sand grain. Sand grains are between gravel (with particles ranging from 2 mm up to 64 mm) and silt (particles smaller than 0.0625 mm down to 0.004 mm). The size specification between sand and gravel has remained constant for more than a century, but particle diameters as small as 0.02 mm were considered sand under the Albert Atterberg standard in use during the early 20th century. A 1953 engineering standard published by the American Association of State Highway and Transportation Officials set the minimum sand size at 0.074 mm. A 1938 specification of the United States Department of Agriculture was 0.05 mm.[1] Sand feels gritty when rubbed between the fingers (silt, by comparison, feels like flour).
ISO 14688 grades sands as fine, medium and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In the United States, sand is commonly divided into five sub-categories based on size: very fine sand (⅟16 – ⅛ mm diameter), fine sand (⅛ mm – ¼ mm), medium sand (¼ mm – ½ mm), coarse sand (½ mm – 1 mm), and very coarse sand (1 mm – 2 mm). These sizes are based on the Krumbein phi scale, where size in Φ = -log base 2 of size in mm. On this scale, for sand the value of Φ varies from −1 to +4, with the divisions between sub-categories at whole numbers.
The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO2), usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is the most common mineral resistant to weathering.
The composition of sand is highly variable, depending on the local rock sources and conditions. The bright white sands found in tropical and subtropical coastal settings are eroded limestone and may contain coral and shell fragments in addition to other organic or organically derived fragmental material, suggesting sand formation depends on living organisms, too.[2] The gypsum sand dunes of the White Sands National Monument in New Mexico are famous for their bright, white color. Arkose is a sand or sandstone with considerable feldspar content, derived from the weathering and erosion of a (usually nearby) granitic rock outcrop. Some sands contain magnetite, chlorite, glauconite or gypsum. Sands rich in magnetite are dark to black in color, as are sands derived from volcanic basalts and obsidian. Chlorite-glauconite bearing sands are typically green in color, as are sands derived from basaltic (lava) with a high olivine content. Many sands, especially those found extensively in Southern Europe, have iron impurities within the quartz crystals of the sand, giving a deep yellow color. Sand deposits in some areas contain garnets and other resistant minerals, including some small gemstones.
Sand is transported by wind and water and deposited in the form of beaches, dunes, sand spits, sand bars and related features. In environments such as gravel-bed rivers and glacial moraines it often occurs as one of the many grain sizes that are represented. Sand-bed rivers, such as the Platte River in Nebraska, USA, have sandy beds largely because there is no larger source material that they can transport. Dunes, a distinctive geographical feature of desert environments, are on the other hand sandy because larger material is generally immobile in wind. Sand is a component of soil.
The study of individual grains can reveal much historical information as to the origin and kind of transport of the grain. Quartz sand that is recently weathered from granite or gneiss quartz crystals will be angular. It is called grus in geology or sharp sand in the building trade where it is preferred for concrete, and in gardening where it is used as a soil amendment to loosen clay soils. Sand that is transported long distances by water or wind will be rounded, with characteristic abrasion patterns on the grain surface. Desert sand is typically rounded.
People who collect sand as a hobby are known as arenophiles. Organisms that thrive in sandy environments are psammophiles.
While sand is generally non-toxic, sand-using activities such as sandblasting require precautions. Bags of silica sand used for sandblasting now carry labels warning the user to wear respiratory protection to avoid breathing the resulting fine silica dust. Material safety data sheets (MSDS) for silica sand state that "excessive inhalation of crystalline silica is a serious health concern".[4]
In areas of high pore water pressure sand and salt water can form quicksand, which is a colloid hydrogel that behaves like a liquid. Quicksand produces a considerable barrier to escape for creatures caught within, who often die from exposure (not from submersion) as a result.
Sand's many uses require a significant dredging industry, raising environmental concerns over fish depletion, landslides, and flooding. Countries such as China, Indonesia, Malaysia and Cambodia ban sand exports, citing these issues as a major factor.[5]
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Dansk (Danish)
n. - sand, (sl) mod
v. tr. - strø sand på, slibe, skure, løbe på en sandbanke
idioms:
Nederlands (Dutch)
zand, schuren, met zand bestrooien
Français (French)
n. - sable, (US) cran (fam), courage
v. tr. - poncer, frotter/passer (qch) au papier de verre, sabler
idioms:
Deutsch (German)
n. - Sand, Sandstrand
v. - streuen, abschmirgeln
idioms:
Ελληνική (Greek)
n. - άμμος, (ΗΠΑ, καθομ.) κουράγιο
v. - προσαμμώνω, τρίβω με γυαλόχαρτο, νοθεύω με άμμο
idioms:
Italiano (Italian)
piallare, sabbia
idioms:
Português (Portuguese)
n. - areia (f)
v. - arear
idioms:
Русский (Russian)
песок, гравий, песчаный пляж, пески, пустыня, песок в песочных часах, время, дни жизни, выдержка, стойкость характера, песочный цвет
idioms:
Español (Spanish)
n. - arena, playa, arenal, arena o suelo petrolífero
v. tr. - lijar, enarenar, mezclar con arena, arena, arenar, cubrir de arena, polvorear con arena, hacer encallar en la arena
idioms:
Svenska (Swedish)
n. - sand, grus, mod (sl)
v. - sanda, blanda med sand
中文(简体)(Chinese (Simplified))
沙, 沙滩, 沙子, 撒沙于, 用沙擦, 撒沙似地布满, 磨光
idioms:
中文(繁體)(Chinese (Traditional))
n. - 沙, 沙灘, 沙子
v. tr. - 撒沙於, 用沙擦, 撒沙似地佈滿, 磨光
idioms:
한국어 (Korean)
n. - 모래, 용기, 설탕
v. tr. - ~에 모래를 뿌리다, 모래로 닦다, ~에 모래를 섞다
idioms:
日本語 (Japanese)
n. - 砂, 砂地, 砂浜, 勇気, 時間, 寿命
v. - 砂で磨く, 砂を撒く
idioms:
العربيه (Arabic)
(الاسم) رمل (فعل) يغطي أو يملأ بالرمل, ينظف أو يصقل بالرمل
עברית (Hebrew)
n. - חול, חוף-הים, דבקות במטרה, כוח-סבל
v. tr. - שפשף בחול, כיסה בחול
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