Sand is one of the major components of most beaches. It is a fine, granular material whose composition varies widely with location. Most sand contains large quantities of the mineral quartz, as well as fine particles of rock and other materials. Sand particles range from 0.65 micrometres to 2 millimetres in size. The fineness or grade of sand found on beaches varies greatly, and ranges from very fine to coarse. Sand is carried to beaches by waves from the shoreline and by the wind, which transports sand from one area of the shoreline to another.
Beach sand contains a variety of materials other than quartz and rock particles. Most ocean beach sand also contains other crystals and small particles of shells and coral that have eroded over long periods of time. Black sand beaches tend to contain large quantities of volcanic ash, and are naturally found in areas with high levels of volcanic activities. White sand beaches contain large quantities of shells. Golden sand beaches contain large quantities of silica or quartz.
Beaches are sources of a variety of minerals. The mineral most commonly found on beaches is quartz, which is a major component of sand. Another commonly occurring mineral is magnetite, which is found in black sand and is what gives the sand its dark color. Other minerals commonly found on beaches are feldspar, calcite and ilmenite.
Beaches are active ecological systems and home to a range of flora and fauna. Some of the most noticeable animals that inhabit beaches are crabs, sand flies, beetles and fish. These animals in turn attract other animals for which they serve as food. Birds feed on the crabs, fish and insects that populate beaches. Some beaches attract larger predators, such as crocodiles. Beaches are home to a diversity of plant life, including algae, micro-fauna, such as plankton, seaweed, grasses and mangroves.