Silicon dioxide is a chemical compound that is also known as silica. Silica sand is a type of sand that mostly consists of tiny granules of quartz. Quartz itself comes in many varieties, according to its color and microstructure. Silica sand also consists of other fine particles of rock and mineral. Granules of silica sand range in diameter from 1/16 mm to 2 mm, which is approximately 2/1000 of an inch to 8/100 of an inch.
All sorts of sands are mined throughout the world, including the very abundant silica sand. Once the sand is mined it is often washed with water to remove salt, silt, clay, dust and powder. Sand also is often separated and classified according to size as it gets washed. Washed sand comes in coarse, medium, fine and ultra fine granule sizes, of which each size classification requires sand granules that are within a specific diameter range. Whatever the size, washed sand isn't necessarily silica sand, and silica sand isn't necessarily washed.
Silica sand is used for many different things, such as sand blasting, glass manufacturing, water filtering, concrete and mortar mixing, landscaping and pool installation, as a spread on top of slick roads, as backfill for electrical lines and pipes, in septic tanks, as part of a loam mix, as well as many other applications.
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I looked it up because I always thought all sand was silica sand.
Caroline