Editing Beach (section)

==Formation==
{{see also|Beach evolution}}
[[File:Scala dei Turchi Sand 062313.jpg|thumb|[[Quartz]] [[sand]] particles and shell fragments from a beach. The primary component of typical beach sand is quartz, or [[silica]] (SiO<sub>2</sub>).]]
[[File:20100726 Kalamitsi Beach Ionian Sea Lefkada island Greece.jpg|thumb|Sand and [[Shingle beach|shingle]] is scoured, [[Particle size (grain size)|graded]] and moved around by the action of waves and currents]]
[[File:Robberg Peninsula - a home of seals.webp|thumb|Beach formed on a wild, untamed rocky coastline]]

Beaches are the result of wave action by which [[wave]]s or [[Ocean current|currents]] move [[sand]] or other loose [[sediment]]s of which the beach is made as these particles are held in [[suspension (chemistry)|suspension]]. Alternatively, sand may be moved by [[Saltation (geology)|saltation]] (a bouncing movement of large particles). Beach materials come from erosion of rocks offshore, as well as from headland [[erosion]] and [[slumping]] producing deposits of [[scree]]. A [[reef|coral reef]] offshore is a significant source of sand particles. Some species of fish that feed on [[algae]] attached to coral outcrops and rocks can create substantial quantities of sand particles over their lifetime as they nibble during feeding, digesting the [[organic matter]], and discarding the rock and coral particles which pass through their digestive tracts.

The composition of the beach depends upon the nature and quantity of [[sediments]] upstream of the beach, and the speed of flow and turbidity of water and wind. Sediments are moved by moving water and wind according to their particle size and state of compaction. Particles tend to settle and compact in still water.  Once compacted, they are more resistant to [[erosion]].  Established vegetation (especially species with complex network root systems) will resist erosion by slowing the fluid flow at the surface layer. When affected by moving water or wind, particles that are eroded and held in suspension will increase the erosive power of the fluid that holds them by increasing the average density, viscosity, and volume of the moving fluid.

[[Coastline]]s facing very energetic wind and wave systems will tend to hold only large rocks as smaller particles will be held in suspension in the turbid water column and carried to calmer areas by longshore currents and tides. Coastlines that are protected from waves and winds will tend to allow finer sediments such as [[clay]] and mud to precipitate creating [[mud flat]]s and [[mangrove]] forests. The shape of a beach depends on whether the waves are constructive or destructive, and whether the material is sand or shingle. Waves are constructive if the period between their [[wave crest]]s is long enough for the breaking water to recede and the sediment to settle before the succeeding wave arrives and breaks.

Fine sediment transported from lower down the beach profile will compact if the receding water percolates or soaks into the beach. Compacted sediment is more resistant to movement by turbulent water from succeeding waves. Conversely, waves are destructive if the period between the wave crests is short. Sediment that remains in suspension when the following wave crest arrives will not be able to settle and compact and will be more susceptible to erosion by [[Longshore drift|longshore currents]] and receding tides. The nature of sediments found on a beach tends to indicate the energy of the waves and wind in the locality.

Constructive waves move material up the beach while destructive waves move the material down the beach. During seasons when destructive waves are prevalent, the shallows will carry an increased load of sediment and organic matter in suspension. On sandy beaches, the turbulent backwash of destructive waves removes material forming a gently sloping beach. On [[pebble]] and shingle beaches the swash is dissipated more quickly because the large particle size allows greater [[percolation]], thereby reducing the power of the backwash, and the beach remains steep. Compacted fine sediments will form a smooth beach surface that resists wind and water erosion.

During hot calm seasons, a crust may form on the surface of ocean beaches as the heat of the sun evaporates the water leaving the salt which [[crystallises]] around the sand particles.  This crust forms an additional protective layer that resists wind erosion unless disturbed by animals or dissolved by the advancing tide. [[Beach cusps|Cusps]] and horns form where incoming waves divide, depositing sand as horns and scouring out sand to form cusps. This forms the uneven face on some sand [[shoreline]]s. White sand beaches look white because the quartz or eroded [[limestone]] in the sand reflects or [[Scattering|scatters]] sunlight without significantly absorbing any colors.

{{anchor|Tropical beach}}<!--linked-->

===Sand colors===
[[File:00065 sand collage.jpg|thumb|Depiction of sands:<br> glass, dune, quartz<br> volcanic, biogenic coral, pink coral<br>volcanic, garnet, olivine]]

The composition of the sand varies depending on the local minerals and geology.<ref name="king">{{cite web |first1=HM |last1=King |title=Sand |url=https://geology.com/stories/13/sand/ |publisher=Geology.com |access-date=14 July 2019 |year=2019}}</ref> Some of the types of sand found in beaches around the world are:
* White sand: Mostly made of [[quartz]] and [[limestone]], it can also contain other minerals like [[feldspar]] and [[gypsum]] .<ref name="king" /><ref name="tips">{{cite web |last1=Stierwalt |first1=Sabrina |title=How does sand get its color? |url=https://www.quickanddirtytips.com/education/science/how-does-sand-get-its-color |website=Quick & Dirty Tips |access-date=14 July 2019}}</ref>
* Light-colored sand: This sand gets its color from quartz and [[iron]],<ref name="king" /> and is the most common sand color in [[Southern Europe]]<ref name="sciencing-sand">{{cite web|title=About Different Types of Sand|url=https://sciencing.com/different-types-sand-4586437.html|website=Sciencing|access-date=28 March 2018}}</ref> and other regions of the [[Mediterranean Basin]], such as [[Tunisia]].<ref name="king" />
* Tropical white sand: On tropical islands, the sand is composed of [[calcium carbonate]] from the shells and skeletons of marine organisms, like [[coral]]s and [[mollusks]], as found in [[Aruba]].<ref name="king" />
* Pink coral sand: Like the above, is composed of [[calcium carbonate]] and gets its pink hue from fragments of coral, such as in [[Bermuda]] and the [[Bahama Islands]].<ref name="king" />
* Black sand: Black sand is composed of [[volcanic rock]], like [[basalt]] and [[obsidian]], which give it its gray-black color.<ref name="king" /> [[Hawaii]]'s [[Punaluu Beach]], [[Madeira]]'s [[Praia Formosa]] and [[Fuerteventura]]'s [[Ajuy, Pájara|Ajuy]] beach are examples of this type of sand.<ref name="king" />
* Red sand: This kind of sand is created by the oxidation of iron from volcanic rocks.<ref name="tips" /> [[Santorini]]'s Kokkini Beach or the beaches on [[Prince Edward Island]] in Canada are examples of this kind of sand.<ref name="tips" />
* Orange sand: Orange sand is high on iron. It can also be a combination of orange limestone, crushed shells, and volcanic deposits.<ref name="tips" /> [[Ramla Bay]] in [[Gozo]], Malta or Porto Ferro in [[Sardinia]] are examples of each, respectively.<ref name="king" />
* Green sand: In this kind of sand, the mineral [[olivine]] has been separated from other volcanic fragments by erosive forces.<ref name="king" /> A famous example is Hawaii's [[Papakolea Beach]], which has sand containing basalt and coral fragments.<ref name="king" /> Olivine beaches have a high potential for [[carbon sequestration]], and artificial greensand beaches are being explored for this process by [[Project Vesta]].<ref name=":02">{{Cite web|title=A Caribbean beach could offer a crucial test in the fight to slow climate change|url=https://www.technologyreview.com/2020/06/22/1004218/how-green-sand-could-capture-billions-of-tons-of-carbon-dioxide/|access-date=2020-11-06|website=MIT Technology Review}}</ref>

{{Gallery
| title        = Types of beach sand
| align        = center
| height = 140
| mode = packed
| File:Hyams_Beach,_Jervis_Bay,_Australia.jpg
 | alt1= White sand
 | Fine, white sand made up of pure [[quartz]] in [[Hyams Beach, New South Wales]], Australia.
| File:Castelldefels September.JPG
 | alt2=Castelldefels
 | Yellow-colored sand in [[Castelldefels]] beach, Spain.
| File: BDA Bermuda.jpg
 | alt3= Bermuda's Pink Sand
 | One of Bermuda's pink-sand beaches at Astwood Park.
| File: 33 - Ajuy.JPG
 | alt4= Black Sand
 | [[Ajuy, Pájara|Ajuy]]'s beach black sand.
| File:Santorini 97.jpg
 | alt5= Red Sand
 | Red sand from [[Santorini]]'s Kokkini beach.
| File: Ramla Bay.jpg
 | alt6= Orange Sand
 | Orange sand from [[Ramla Bay]], Malta
| File:Green sand closeup 1.jpg
 | alt7= Green Sand
 | Close view of [[Papakolea Beach]]'s green sand.
| File:Carters Beach- Sand.jpg
 | alt8= Grey sand
 |Grey sand at [[Carters Beach]], New Zealand
}}