question: How fine can sand get?
comment: The fineness of sand is dependent on the size of the particles of the sand. Find sand is very small particles. Coarse sand is larger. However, if sand gets too big of particles, it is no longer called sand. It is instead called gravel. Similarly, if sand gets too small, it is no longer called sand, and instead it is considered silt. Go smaller than silt, and it becomes clay. Different industries set the standard sizes for what exactly defines each of these categories. According to the Unified Soil Classification System (USCS), which governs the use of soils for engineering purposes, sand is defined as having particle sizes between 0.74 and 4.75 mm. So to answer your question, sand can get as small as 0.74mm in diameter. However, stuff can get smaller, it's just no longer defined as sand. Check this out for further reading. URL_0
passages: The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO), usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is the most common mineral resistant to weathering.
   Section::::Sources.
   The most important material characteristic is the sediment grain size, which must closely match the native material. Excess silt and clay fraction (mud) versus the natural turbidity in the nourishment area disqualifies some materials. Projects with unmatched grain sizes performed relatively poorly. Nourishment sand that is only slightly smaller than native sand can result in significantly narrower equilibrated dry beach widths compared to sand the same size as (or larger than) native sand. Evaluating material fit requires a sand survey that usually includes geophysical profiles and surface and core samples.
   Section::::Habitat.
   Sand is a non-renewable resource over human timescales, and sand suitable for making concrete is in high demand. Desert sand, although plentiful, is not suitable for concrete. 50 billion tons of beach sand and fossil sand is used each year for construction.
  
  Section::::Composition.
   In Dubai, United Arab Emirates, the use of sand has been very demanding in the construction of infrastructure and creating new islands. They used up their own reserves and now import most of their sand from Australia. There have been three projects to create artificial islands needing more than 835 million tonnes of sand, which cost more than US$26 billion.
  
  Section::::See also.
  
  BULLET::::- (EMC)
  
  Section::::External links.
  
  BULLET::::- "Beach Sand: What It Is, Where It Comes From and How It Gets Here" - Beaufort County Library
  
  BULLET::::- Sand mining side-effects
   While sand is generally non-toxic, sand-using activities such as sandblasting require precautions. Bags of silica sand used for sandblasting now carry labels warning the user to wear respiratory protection to avoid breathing the resulting fine silica dust. Safety data sheets for silica sand state that "excessive inhalation of crystalline silica is a serious health concern".
   Sand is cheap and easily available. However, it is heavy, does not hold water very well, and it must be sterilized between uses.
  
  Section::::Substrates (growing support materials).:Gravel.
   Only some sands are suitable for the construction industry, for example for making concrete. 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. In 2012 French director Denis Delestrac made a documentary called "Sand Wars" about the impact of the lack of construction sand. It shows the ecological and economic effects of both legal and illegal trade in construction sand.
   The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO), usually in the form of quartz. The second most common type of sand is calcium carbonate, for example, aragonite, which has mostly been created, over the past half billion years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean.
   Sand's many uses require a significant dredging industry, raising environmental concerns over fish depletion, landslides, and flooding. Countries such as China, Indonesia, Malaysia, and Cambodia ban sand exports, citing these issues as a major factor. It is estimated that the annual consumption of sand and gravel is 40 billion tons and sand is a US$70 billion global industry.
  
  The global demand for sand in 2017 was 9.55 billion tons as part of a $99.5 billion industry.
  
  Section::::Hazards.
   Only three places on earth have green sand; recently a supply has been found in Brazil. The rarest sands, from a collector's perspective, are found at Pitcairn's Island and Easter Island. Some sands, such as rare black and green sands in Hawaii, may not be collected due to their scarcity. The "International Sand Collectors Society" advises collectors become aware of any legal restrictions or permissions that may be required to collect sand from any public or and private location. The International Sand Collectors Society fosters contact for tips and sample swapping among collectors worldwide.
  
  Section::::Further reading.
   People who collect sand as a hobby are known as arenophiles. Organisms that thrive in sandy environments are psammophiles.
  
  Section::::Uses.
  
  BULLET::::- Abrasion: Before sandpaper, wet sand was used as an abrasive element between rotating devices with elastic surface and hard materials such as very hard stone (making of stone vases), or metal (removal of old stain before re-staining cupper cooking pots).
  
  BULLET::::- Agriculture: Sandy soils are ideal for crops such as watermelons, peaches, and peanuts, and their excellent drainage characteristics make them suitable for intensive dairy farming.
   Section::::Requirements for effective nourishment.
  
  Sand fill must be compatible with native beach sand.
  
  Section::::Requirements for effective nourishment.:Profile Nourishment.
   BULLET::::- "Sand" ("Charlie Jade"), an episode of the television series "Charlie Jade"
  
  BULLET::::- "Sand", an episode of the television series "Blake's 7"
  
  Section::::Places.
  
  BULLET::::- Sand, Applecross, Scotland
  
  BULLET::::- Sand, Bas-Rhin, France
  
  BULLET::::- Sand, Chur, Switzerland
  
  BULLET::::- Sand, Hedmark, Norway
  
  BULLET::::- Sand, Hungary
  
  BULLET::::- Sand, Iran (disambiguation)
  
  BULLET::::- Sand, Meiringen, Bern, Switzerland
  
  BULLET::::- Sand, Rogaland, Norway
  
  BULLET::::- Sand, Shetland Islands, United Kingdom
  
  BULLET::::- Sand, historic name (1837–1886) for the former municipality of Bjarkøy, Norway
  
  BULLET::::- Sand am Main, Bavaria, Germany
  
  BULLET::::- Sand City, California
  
  BULLET::::- Sand Creek (disambiguation)
  
  BULLET::::- Sand Hill (disambiguation)
  
  BULLET::::- Sand Island (disambiguation)
  
  BULLET::::- Sand Lake (disambiguation)
   Availability/cost — The availability and cost of the sand is very important because for every ton of metal poured, three to six tons of sand is required. Although sand can be screened and reused, the particles eventually become too fine and require periodic replacement with fresh sand.
   Some collectors have included sand from rivers and mineral deposits if they meet the criteria according to diameter and physical properties, ensuring that the samples have met proper sand definition. 
   Section::::Dunefields.:Sediment.
   Typical physical measures include dry beach width/height, post-storm sand volume, post-storm damage avoidance assessments and aqueous sand volume.
  
  Environmental measures include marine life distribution, habitat and population counts.
  
  Economic impacts include recreation, tourism, flood and "disaster" prevention.
   BULLET::::- silica sand (SiO), chromite sand (FeCrO), or zircon sand (ZrSiO), 75 to 85%, sometimes with a proportion of olivine, staurolite, or graphite.
  
  BULLET::::- bentonite (clay), 5 to 11%
  
  BULLET::::- water, 2 to 4%
  
  BULLET::::- inert sludge 3 to 5%
  
  BULLET::::- anthracite (0 to 1%)
   Sand is best known for his role in a 1924 bribery incident that resulted in two players being banned from baseball by Commissioner Kenesaw Mountain Landis. Sand knew New York Giants player Jimmy O'Connell from their days in San Francisco. On September 23, the Phillies were out of contention, and O'Connell offered to pay $500 to Sand if he would "go easy" on the Giants. The incident came to the attention of Judge Landis, who conducted a hearing. O'Connell admitted making the offer and implicated Giants coach Cozy Dolan in the scheme. Landis banned both O'Connell and Dolan from baseball.
   Section::::Global sand and beach theft.:Greece.
  
  The pink sands of Elafonisi, created by tidal and wave-induced deposits of pigmented microorganisms living in a symbiotic relationship with native seaweed, were a frequent subject of souvenir-taking by tourists until the Greek government declared the area a nature reserve and prohibited the sands' removal; even today, color saturation levels remain at only around 10% of those in the early twentieth century.
  
  Section::::Effects.
   As of 2013, industrial frac sand mining has become a cause for activism, especially in the Driftless Area of southeast Minnesota, northeast Iowa and southwest Wisconsin.
  
  Section::::By country.:China.
  
  Much sand is extracted by dredges from the bottom of rivers such as the Red River in Yunnan, or quarried in dry river beds. Due to the large demand for sand for construction, illicit sand mining is not uncommon.
  
  Section::::See also.
  
  BULLET::::- Heavy mineral sands ore deposits
  
  BULLET::::- Beach theft
  
  BULLET::::- Resource depletion
  
  BULLET::::- Sand mining in Tamil Nadu
  
  BULLET::::- Sand mining in Kerala
  
  BULLET::::- Environmental issues with mining
  
  Section::::External links.
   The depth of the sand bed is recommended to be around 0.6–1.8 m (2–6 ft) regardless of the application. This is linked to the maximum throughput discussed below.
  
  Guidance on the design of rapid sand bed filters suggests that they should be operated with a maximum flow rate of 9 m/m/hr (220 US gal/ft/hr). Using the required throughput and the maximum flow rate, the required area of the bed can be calculated.
   Section::::Formation.:Sand colors.
  
  The composition of the sand varies depending on the local minerals and geology. Some of the types of sand found in beaches around the world are:
  
  BULLET::::- White sand: Mostly made of quartz and limestone, it can also contain other minerals like feldspar and gypsum.
  
  BULLET::::- Light-colored sand: This sand gets its color from quartz and iron, and is the most common sand color in Southern Europe and other regions of the Mediterranean Basin, such as Tunisia.
  