<P> The exact definition of sand varies . The scientific Unified Soil Classification System used in engineering and geology corresponds to US Standard Sieves , and defines sand as particles with a diameter of between 0.074 and 4.75 millimeters . By another definition , in terms of particle size as used by geologists , sand particles range in diameter from 0.0625 mm ( or ​ ⁄ 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 by the latter system , and from 4.75 mm up to 75 mm in the former ) 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 . The grains of sand in Archimedes Sand Reckoner written around 240 BCE , were 0.02 mm in diameter . 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 . Sand feels gritty when rubbed between the fingers . Silt , by comparison , feels like flour ) . </P>
<P> The exact definition of sand varies . The scientific Unified Soil Classification System used in engineering and geology corresponds to US Standard Sieves , and defines sand as particles with a diameter of between 0.074 and 4.75 millimeters . By another definition , in terms of particle size as used by geologists , sand particles range in diameter from 0.0625 mm ( or ​ ⁄ 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 by the latter system , and from 4.75 mm up to 75 mm in the former ) 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 . The grains of sand in Archimedes Sand Reckoner written around 240 BCE , were 0.02 mm in diameter . 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 . Sand feels gritty when rubbed between the fingers . Silt , by comparison , feels like flour ) . </P>
what type of rock is made of particles .05 cm
what type of rock is made of particles .05 cm
Sand
Sand