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small fragments of loose sedimentary rock or contemporary sediment. Sand consists of round and angular grains of various minerals and rock fragments ranging from 0.1 to 1 mm (from 0.05 to 2 mm or larger, according to other classifications). It also has admixtures of silt (aleurite) and clay particles.
Sand may be designated by its origin as river, lake, sea, fluvioglacial, or eolian sand. In terms of mineralogical composition the most common sands are quartz, glauconite-quartz, feldspar-quartz, and mica sands. Sand may contain valuable minerals— gold, platinum, diamonds, sapphires, rubies, zircon, rutile, sphene, and ilmenite—some of which are extracted. Both natural sand and man-made sand, produced by crushing rock, are used in construction and in the building-materials industry. Quartz sand is used as a raw material in making glass, as a component in manufacturing porcelain, earthenware, and construction ceramics, and as material for making casting molds. The quality of sand is determined by the size of its grains, its mineralogical composition, and the amount of impurities.
Sorted sand must have a strictly regulated grain composition. Natural sand is usually supplied in two grades: large (5–0.63 and 5–1.25 mm) and small (1.25–0.14 and 0.63–0.14 mm). Impurities may not exceed 2 percent. There are two grades of crushed sand, 800 and 400, depending on the strength of the original rock.
REFERENCESFadeev, P. I. Peski SSSR, part 1. Moscow, 1951.
Trebovaniia promyshlennosti k kachestvu mineral’nogo syr’ia, 2nd ed., issues 2, 29, 74. Moscow, 1959–63.
Grauvakki. Moscow, 1972.
What does it mean when you dream about sand?
A dream about sand might relate to pleasant memories of being at the beach. Alternatively, sand can represent time—as in “the sands of time”—or the insecurity of building one’s house in the sand. Sand is also associated with deserts and the lack of nourishing water. (See also Beach, Desert).