Sand is a naturally occurring, finely ground
rock (diameter 0.02 to 2
millimetres) that is transported by wind or water and deposited in the form of
beaches,
dunes etc.
Deserts are often composed of sand. The composition of sand varies according to local conditions. Much of the fine white sand found on
coral island beaches, for example, is ground-up coral that has passed through the bowels of schools of
trigger fish[?]. The commonest constituent of sand, however, is
silica (
silicon dioxide), often in the form of
quartz. Some places have sands that contain
iron or
feldspar.
People, especially children, love to play with sand on a beach or in a sandbox. On beaches they make a mountain, a pit, canals, tunnels, a statue, a building (such as a sand castle), etc.
See also: List of minerals.