Sand is a mixture of very small pieces of different rocks or minerals such as granite and feldspar and sand stone. Sand grains are between the size of gravel grains (which is from 2 mm to 64 mm) and the size of silt (which is around 0.0625 mm to 0.004 mm). It is found on beaches, and in deserts.
Sand is most of the time made of silica (silicon dioxide, or SiO2). Sand is also formed by Granite by weathering and erosion. Sand is made from large boulders eroding (being broken apart by wind or rocks). They get smaller and smaller until they reach the beach or a low lying area. Sand dunes are made when wind or a river pulls sand into a mountain-like shape. They can be found in deserts, but sometimes high up on beaches too.
It can also be used to make sand castles.
Sand on a beach in Calabria. You can see sand dunes here.
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