The sand that we see
A sandy beach is made up trillions of tiny grains of rock ranging from 0.0625 to 2 millimetres across. Each beach has its unique mix of sand: the white tropical beaches in holiday brochures often have a lot of crushed limestone, while darker beaches usually consist of quartz, a mineral composed of a chemical compound called silicon dioxide. There are also black and green beaches made of ground volcanic rocks containing various minerals.
Shores made up of grains measuring 2mm to 64mm are called gravel beaches; grains that only measure 0.0625mm to 0.004mm are called silt.
Sand is used in many industries: the building trade uses it to make concrete, glass and bricks; farmers add it to soil to grow crops like watermelons, peaches and peanuts; and landscapers use it to create features for gardens and golf courses.