Sand

It is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years, as in the Caribbean.

The scientific Unified Soil Classification System used in engineering and geology corresponds to US Standard Sieves, and defines sand as particles with a diameter of between 0.074 and 4.75 millimeters.

[7] A 1953 engineering standard published by the American Association of State Highway and Transportation Officials set the minimum sand size at 0.074 mm.

The composition of mineral sand is highly variable, depending on the local rock sources and conditions.

Arkose is a sand or sandstone with considerable feldspar content, derived from weathering and erosion of a (usually nearby) granitic rock outcrop.

Rocks erode or weather over a long period of time, mainly by water and wind, and their sediments are transported downstream.

Over time, wind blows away fine particles, such as clay and dead organic matter, leaving only sand and larger rocks.

Weathering and river deposition also accelerate the process of creating a beach, along with marine animals interacting with rocks, such as eating the algae off of them.

Sand that is transported long distances by water or wind will be rounded, with characteristic abrasion patterns on the grain surface.

Because of the growth of population and of cities and the consequent construction activity there is a huge demand for these special kinds of sand, and natural sources are running low.

This works by pumping the top few meters of sand out of the water and filling it into a boat, which is then transported back to land for processing.

All marine life mixed in with the extracted sand is killed and the ecosystem can continue to suffer for years after the mining is complete.

When sand is taken out of the water it increases the risk of landslides, which can lead to loss of agricultural land and/or damage to dwellings.

[21] Sand's many uses require a significant dredging industry, raising environmental concerns over fish depletion, landslides, and flooding.

[22] Countries such as China, Indonesia, Malaysia, and Cambodia ban sand exports, citing these issues as a major factor.

[26] In April 2022, the United Nations Environment Programme (UNEP) published a report stating that 50 billion tons of sand and gravel were being used every year.

The report made 10 recommendations, including a ban on beach extraction, to avert a crisis, and move toward a circular economy for the two resources.

Quicksand produces a considerable barrier to escape for creatures caught within, who often die from exposure (not from submersion) as a result.

People sometimes dig holes in the sand at beaches for recreational purposes, but if too deep they can result in serious injury or death in the event of a collapse.