Sand is an irreplaceable material in construction. But, before using it, you need to know about its technical characteristics and features. Different types of sand have different characteristics. Therefore, when buying, you should check its chemical and fractional composition, the presence of impurities, pay attention to the brand and other important factors.
What is river sand, description and composition
All natural sand is subdivided into several types that differ in many factors. The most popular in construction is river sand.
Washed
Smooth, uniform grains of yellow or gray are obtained from the bottom of the rivers. They include oxides of silicon and iron. Its chemical formula is SiO2. In river sand, there are usually no particles of clay and other impurities, since it is washed naturally. Mostly grains of sand are of medium size.
Coarse-grained
Most of all, coarse-grained river sand is valued, which is much less common, for this reason it costs much more. It is usually mined in dry river beds. This type of sand is used for finishing, masonry, design work. It is a part of road coatings and is used in brick production.
Coarse sand has a neutral, unobtrusive color; it is excellent for furnishing the design of personal gardens.
Large
Coarse sand differs from coarse river sand. It is mined from rocks by splitting stones using specialized crushing and grinding equipment. Its size module can be up to 5 mm.
Fractions
River sand is divided into the following types:
- dusty;
- coarse-grained;
- medium-grained;
- clayey
The sand is sorted by grain size, sifting it through special sieves.
Differences and features of river sand
River sand differs from other types of sand primarily in its natural purity; it contains no clay particles, small pebbles and other impurities. Its second difference is fractional homogeneity. Dry mixes are made from river sand for construction work.
It is used as an aggregate for floor screeds, it is the main component for the production of asphalt concrete. With its help, drainages are equipped, used as a filter at treatment plants. Sand perfectly cleans water from mechanical impurities. In household plots, soil is mixed with river sand to make it lighter, crumbly.
More details on the video:
Difference from sea
The river sand is almost no different from sea sand. Sea sand has high quality characteristics, does not contain natural impurities, since it undergoes a two-stage enrichment during extraction. Therefore, concrete mixtures and mortars are prepared from it.
Difference from career
Which sand is better - quarry or river - depends on the characteristics of the further scope of their application. Quarry sand, as the name implies, is mined in quarries or crushed gravel and other rocks using special devices. Usually it contains a large amount of impurities of stones and clay.
Quarry sand is easy to mine and of high quality, but due to the organic impurities it contains, the sand often behaves unpredictably, reacting with chemical additives in the solution. Quarry sand is also not suitable for filtering; washed quarry sand is often used for concrete.
Extraction of sand from water with a brief description of the process
Sand is extracted from deep rivers using a dredger, which is fixed to a barge. Such dredgers are equipped with special hydromechanical equipment, with powerful pumps, reservoirs and sieves for dividing sand by composition.
Rippers, lowered to the bottom of the river, mechanically suck in the sand. The sand is transported along the slurry pipeline to the surface and stacked on the barge platform, which is called the dump. It has a device for draining water. After that, the sand is dry cleaned and loaded onto another barge.
The extraction of river sand from the beds of dried up rivers is similar to the quarry. All sand obtained must have a certificate of conformity.
In the video: amphibious excavator-dredger, sand reclamation at 400 m:
Specifications and properties
When buying river sand, you must require a passport and a certificate for it. The characteristics of river sand must meet GOST 8736-93.
The main properties of river sand
The particles of river sand are of different sizes. According to them, this material is classified into the following groups:
- fine sand with grains up to 2 mm in size;
- medium sand - from 2 to 2.5 mm;
- coarse sand - over 2.5 mm.
For building sand, two types of specific gravity are distinguished - bulk and true. Bulk density (density) is the amount of material placed in a unit of volume. Due to its high flowability, it is very difficult to determine the mass of sand in a cubic meter.
The true specific gravity is calculated in laboratories; in practice, its values \u200b\u200bare usually not used. In practice, they use bulk specific gravity, this is the amount of sand that enters a container measuring 1 cubic meter.
Application of river sand
The areas where river sand is successfully used are not limited.
It is used:
- For the production of concrete products, sand increases their strength and frost resistance;
- For the manufacture of dry mixes;
- For the formation of foundation cushions
- In the production of mortars for plastering and masonry works
- When screed and masonry;
- For room decoration
- For the improvement of the territory
- In landscape work
- For the arrangement of playgrounds.
- Sand for making concrete
River sand is irreplaceable in construction, with the help of it concrete is produced, from which various products are made. You cannot do without it in finishing work. River sand meets all building requirements, but builders who prepare mortars do not like it because it settles very quickly, so it has to be constantly mixed.
Photo of river sand 
For sandbox
The best option for a children's sandbox is river sand. It does not contain sulfites, sulfur, and other harmful particles that can harm a child. It is better to take sand of the middle fraction for the sandbox.
For aquariums
For constant water purification in an aquarium, river sand must be poured into it. It is better to use coarser, darker colored sand, as light sand causes discomfort for fish living in the aquarium.
Is it possible to paint river sand
River sand of different colors can often be seen in decorative works. To do this, it is specially painted with gouache, tempera powder or food colors. Ready paints are poured into jars and sifted sand is poured into them. After a while, it is taken out and dried. In addition to all of the above, sand can be easily given any color using ordinary multi-colored crayons.
How to paint river sand with crayons can be seen in the video:
Advantages and disadvantages
River sand has no disadvantages, except for the high cost of this natural material.
But there are a lot of positive qualities:
- ecologically pure;
- not afraid of exposure to aggressive components;
- has high moisture resistance;
- it is an excellent soundproofing material;
- sand is not subject to decay;
- meets high technical and aesthetic requirements.
You can endlessly list its benefits, so users give this natural material the highest ratings.
Sand is an irreplaceable material in the construction industry. It, like any building material, has its own individual characteristics and application features.
River sand
The river sand used by the builders has a personal fractional and chemical composition; it is the most demanded material among its analogues.
Washed sand
Grains of uniform color (yellow or gray) with perfectly smooth surface are at the very bottom of the river. Iron and silicon oxides can be found in this sand. In the river sand there is practically no presence of clay impurities and other third-party debris, because this type of sand is washed in its natural environment. The size of each grain of sand is small, it is generally considered average.
In the construction industry, however, the coarse-grained type of river sand is considered to be more valuable. Such material is extremely rare, as a result of which it is expensive. Sand can be found in any bed of a dry river. This type of sand is successfully used for masonry, finishing, as well as design work. It is included in compositions for covering highways, used to make bricks.
Coarse river sand has unobtrusive color, a neutral shade, it is perfect for decor used on a personal plot.
Coarse river sand
This type of sand is usually mined from rocks found in rivers. Boulders are split using specialized equipment, and subsequently the resulting parts are crushed and split. The largest grain of sand can reach 5 millimeters in diameter.
Fractions
River sand is known for the following fractions:
- Dusty.
- Medium-grained.
- Coarse-grained.
- Clayy.
According to the grain size, the sand is calibrated using a special sieve with cells of different diameters.
Sand mining
It is customary to extract river sand using a dredger, which in turn is fixed on a barge. The dredger has specialized mechanical equipment, which includes:
- Powerful pumps.
- Sand collection tanks.
- Sita.
The purchase of river sand must be started with a look at its passport and certificate, in which the characteristics must meet GOST - 8736-93.
Applications of river sand
This material is usually used for:
- Production of concrete and concrete products (sand helps to maintain their strength for a long time and increases their frost resistance).
- Manufacture of dry building mixtures.
- Creation of foundation cushions.
- Production of mortars required for masonry and plastering works.
- Room decoration.
- Filling aquariums.
- Arrangement of playgrounds for children and so on.
Benefits of river sand
- Environmentally friendly product.
- Possesses high moisture resistance.
- Ideal soundproofing material.
- Over time, it does not rot.
- Meets most technical requirements.
Quarry sand is presented as loose rock, in the composition of which you can find with the naked eye grains of feldspar, quartz, mica and other minerals found in natural conditions.
In the construction industry, quarry sand is a very popular material, which is directly related to its good natural properties and low price.
It is used not only in the field of construction, but also such sand has found its wide application in the fields of industry and agriculture.
Quarry sand is extracted in the following way - loose rock is dug in large layers. Subsequently, such sand is subjected to screening and washing. It refers to GOST - 8736-93.
Size classification:
- Fine-grained - no more than 2 millimeters in diameter.
- Medium-grained - 2 - 2, 8 mm.
- Coarse - up to 5 millimeters.
Varieties of quarry sand
- Alluvial(washed sand) - this type of quarry sand is usually mined on flooded deposits and fields using hydromechanical equipment. The sand, thanks to this technology, turns out to be clean, there are no impurities and unnecessary components in it.
- Seeded sand - quarry sand is sifted from stones and large particles.
- Sandy soil - unrefined quarry sand is mixed with various components, the cost of the material is very low.
Applications:
- Construction.
- National economy.
- Industry.
- Applied art.
Benefits
- The sand is sold uncleaned, as a result of which the enterprises that extract quarry sand and sell it can save on cleaning and screening.
- The mining process is quite simple, as a result of which the material itself is cheap.
- Delivery of quarry sand is carried out at low prices.
Common between river and quarry sand
- They are used in the construction industry.
- They have the same indicators according to GOST.
- Used for decoration.
Differences
- The methods of extracting sand vary.
- River sand is considered a cleaner material, since, unlike quarry sand, only fragments of clay can be found in it.
- Quarry sand is a cheaper building material.
- River sand is distinguished by its environmental friendliness.
- For children's sandpits and aquariums, it is most advisable to choose river sand.
In uncovering and examining the history of our planet, geologists are faced with a fascinating scenario written by nature. The history of the development of the Earth is a colorful and vivid performance full of dramatic events, many of the participants and spectators of which have long gone into oblivion, leaving their mark on the earth's layers. Each layer, each layer of the earth's crust is like a page of a huge stone book. On these pages, in a peculiar language in the form of plant prints and animal fossils; traces of storms sweeping over the Earth, recorded events that took place on the Earth and in its depths many hundreds of millions and billions of years ago.
Like forensic scientists, geologists slowly and scrupulously, step by step, find and study facts, build various hypotheses (assumptions, guesses), recreate pictures of the distant past from oblivion. For several centuries now, naturalists and geologists have been trying to reconstruct the history of the Earth. But it is still full of mysteries.
The innumerable mineral wealth - coal and brown coal, iron, manganese, aluminum, copper and other ores, gold, marble and many building materials have always aroused great interest in people. Adults always use these riches.
After all, you are always curious about what you can get. How to use this wealth for the benefit of all mankind.
Curiosity. It all starts with him.
For example:
Millions of boys and girls have been playing with great pleasure in a simple but terribly exciting and interesting game for many decades now.
It is yellow and free-flowing
It is piled in a heap in the yard.
If you want you can take
And play with friends.
It is impossible to find a person on Earth who does not know what it is: sand. For some, the sand has become a game, for some a medicine, and for some a tragedy.
And yet, what is it\u003e?
Every summer, with great pleasure, I spend time in one of my favorite places - the sandbox. From early childhood, I was fascinated by these tiny grains of sand, which, if they fall one by one in the eye, it will be very unpleasant, but if they are put together one by one, you can create unique shapes.
When it is dry, it pours like a river, but if it is moistened with water, it becomes sticky like snow.
Having looked into the explanatory dictionary of S. I. Ozhegov, I discovered that sand is loose grains of quartz or other solid minerals. (S. I. Ozhegov Dictionary of the Russian language., Ed.\u003e, M., 1973).
In\u003e V. I. Dahl, I read that\u003e.
Explanatory dictionary of the Russian language D. N. Ushakov gives the following definition:\u003e.
From everything I read, I realized that sand is a product of the destruction of various rocks. By the size of the grains, they are distinguished: crushed stone, gravel, coarse, fine sand and sand dust. At the location of the sand is: river, sea (dunes), ravine, mountain. By composition - quartz, limestone, magnetic, gold-bearing. This is why he is so popular. And it is used almost everywhere.
Let's consider everything in order.
And so: What is sand?
No, not sugar, but the one on which it is so pleasant to lie on a hot summer day. Especially if it's not just sand, but a beach.
When solid rock was exposed to wind, rain, and frost, it shattered into small pieces. If these particles are small enough (from
0.05mm to 2.5mm in diameter), they are called sand.
So, sand is what is left of rocks, boulders, ordinary stones. Time, wind, rain, sun and time again destroyed the mountains, showered rocks, pounded boulders, shattered stones, turning them into billions of grains of sand, making them sand. So our beloved river, sea and other sand consists of quartz, feldspar and mica.
Since sand is the fine mineral particles that make up mountains, any mineral can be found in the sand. The main material of which the sand is composed is quartz. Some sands contain 99% quartz. Other minerals that can be found in sand are calcite, mica, iron ore, in small amounts - garnet, tourmaline, topaz.
Sand can be found wherever mountains are naturally affected. One of the places with the greatest sand occurrence is the seashore. Here the impact of tides, their destructive effect on mountains, friction against mountains of applied sand and dissolution of some mountain minerals with salt water affects. All this together contributes to the formation of sand.
But where does the sand in the deserts come from?
Most of the sand is blown into the desert by the wind. In some cases, desert sand is formed by the destruction of mountains. There are cases when deserts were originally the seabed, but the water receded millennia ago. Bare desert sands that can move are called dunes.
Sand is a very useful material. It is used in the manufacture of concrete, glass, sandpaper, filters for water purification.
Since sand is 99% quartz, then: What is quartz?
We use quartz every day in everyday life and do not even think that it is quartz. Quartz is very widespread and has many uses.
Quartz is also called silica. It is composed of silicon and oxygen, heavier than steel and stronger than glass.
Without impurities, quartz is colorless or white, various additives make it red, brown, green, blue, blue, even black. Sometimes quartz is found in the form of large transparent hexagonal crystals with sharp ends - this is\u003e.
Most of the mountains are composed of quartz. Sandstone is composed of quartz particles bonded together with a cementitious compound. The composition of granite also includes quartz. White sands are pure quartz. Plain sand is also mostly quartz! Many of the semi-precious stones are also quartz colored with various impurities. For example, agate, amethyst, onyx.
Why is the sand different colors?
There is a lot of sand on Earth. It is enough to imagine sandy deserts, in which mountains of sand (dunes) sometimes stretch for tens and hundreds of kilometers, or sea coasts with sand dunes intertwined by the wind, if they are not held together by pine roots. In the deserts of Central Asia and Kazakhstan, the sands occupy at least a million square kilometers.
The color of the sand is different - black, greenish, reddish, although yellow and white sand is most common. The color of the sand depends on its origin. Sand appears after the destruction of solid rocks under the influence of fluctuations in temperature, wind or water. This process is especially intense in the zone of constant sea surf or rapids in mountain rivers. The resulting sand is grayish in color, like most types of granite.
The coastal cliffs gradually split into separate blocks, which turn into stones and pebbles in waves. For many years, the waves rub them against each other and gradually crush them into smaller and smaller particles. They are also hewn and gradually turn into a mass of uniform particle size. Small pieces of corals and shells shattered by the sea are often added to it.
Sometimes sand is brought to the coast by winds. Such, for example, is the composition of the Mediterranean coast, where the sand is brought by the wind from the Sahara Desert. This sand is bright yellow in color and consists of small pieces of quartz. The pink sands are made of feldspar. The red ones are from garnierite.
Some beaches are made of only one color of sand, such as the black lava beaches in Tahiti. White sand, consisting of the remains of coral and shells, is found on the atolls and coasts of tropical seas. In Europe, it can be seen in fossil deposits, almost entirely composed of calcareous compounds.
There are amazing black sands in Azerbaijan, near the city of Lankaran. They were formed from deep, black gabbro rocks.
But much more often the sands are a mixture of colors, since they consist of different types of rocks with an admixture of fragments of coral and shell rock.
We have learned a lot of good things about sand, and it seems that on Earth there is nothing more important and valuable than sand. One gets the impression that life without sand would be boring and difficult. But why, then, are so many so afraid of such wonderful and irreplaceable sand?
Why is he so scary? The harm done by sand.
On Earth, more than half of the land surface is desert and steppe. In these spaces, sandstorms arise, develop and rage. There is a place for them to roam with all their might!
As soon as the morning rays warm up the earth, the winds begin to work: they carry a huge amount of dust, pour and blow millions of tons of sand. And travelers are poisoned by existence, for neither heat nor lack of water bring people such troubles as sandstorms.
A sure sign that a dry wind is approaching (a dry wind is a dry hot wind that brings a prolonged drought) or a sandstorm is a haze on the horizon. A little time will pass - and the daylight will dim: it will be covered with a cloudy veil. But these are not clouds carrying a blessed rain, but a canopy of the finest dust raised by the winds.
Where dry winds and sandstorms have passed, plants fade, dry up and die. \u003e - this is how people called these evil winds.
A sandstorm is a very terrible phenomenon, it is an element that lifts tons of sand and dust into the air; they are common in arid and desert regions. The most famous African sandstorms in the Sahara.
The Sahara Desert - the largest desert on Earth, covers an area of \u200b\u200b9 million square kilometers in North Africa. This is one of the areas of the Earth with the most unfavorable living conditions. The air temperature often reaches 55 degrees, and the soil temperature - 80. Many thousands of people died in the sands of this desert. Whole caravans carrying slaves, ivory, gold or salt disappeared into the desert without a trace.
Another scary phenomenon from sand is sand dunes (dunes are coastal sand hills, drifts moved by the wind). They are often found in deserts, but also occur on the sea coasts, on the shores of lakes. Dune movement can lead to dire consequences for people. Sand covers forests, fields, roads, buildings and entire villages. To stop the sand, various measures are used: vegetation, mechanical barriers.
Petrified dunes can be found in some places. Sometimes this indicates that in the past there was a desert on this place. In many places around the globe, people have lived in fear of quicksand for centuries. They were credited with the mysterious ability to suck in a victim until a trace of it remains on the surface of the earth.
Quicksands are sands with very fine grains of sand containing a large amount of water. Unlike ordinary grains of sand, which have an irregular or pointed shape, quicksand grains are small round balls. Heavy objects here very easily disappear from the surface, as if sucked in by the sand. Unlike ordinary sands, quicksand is not elastic at all. Therefore, walking on them is extremely dangerous - you can simply\u003e.
What is quicksand, or, as it is also called, quicksand?
It is light, loose sand with a high water content. In appearance, it does not differ in anything from the ordinary sand that is next to it. However, there is still a difference between them: quicksand is not a support for heavy things.
Most often, quicksands are found in swampy places, on the shores of the seas, in river mouths.
People trapped in quicksand can be saved. Since they contain a lot of moisture, they can float just like in water. You just need to remember that once you hit them, you need to move slowly enough. This allows the sand to flow around your body, as happens when you float in water. In this case, you can save your life.
If sand is so dangerous, then: How do plants and animals manage to live in the sand? There are many different types of deserts. In some, there is a scorching heat for a whole year, from which even the sand groans. In others, a very cold winter comes to replace the sultry summer. In each of the deserts, only special species of animals and plants can exist. Shrub plants living in deserts have very little or no leaves. The small foliage surface prevents too much moisture from evaporating from the plant. Mexican cacti, for example, have thick, fleshy stems and thorns instead of true leaves. Many plants have thorns and needles, while others have an unpleasant taste and smell. Thus, they protect themselves from animals and do not allow themselves to be eaten.
Animals that live among the sands, without exception, can do without water for a long time and get to sources that are at a great distance from each other. The best example of a desert dweller is the camel. He has special pads on his feet to make it easier to walk on the hot sand, a stomach in which water accumulates, a fat hump - a reserve of energy needed during long transitions, and tight nostrils that prevent sand from entering the lungs during sandstorms.
Many of the little desert dwellers do not drink water at all. They get moisture from plant sap and night dew on leaves and stones.
People came up with the idea of \u200b\u200bgrowing watermelons in deserts. Yes, I was not mistaken, it was watermelons. And they grow big, up to 10 - 12 kilograms. There are melons, which we all know, but there are also rain-fed ones: very sweet, with a salty taste. How do you manage to grow them among the sea of \u200b\u200bsand, without watering, under the scorching sun?
This is done simply. In early spring, the nomad goes to rake the sand next to saxaul or camel thorn. The inhabitant of the sands knows that the roots of desert plants go deep into the depths, where there is water, salt, and the coolness necessary for all living things.
It is necessary to dig up the earth approximately to the elbow, make an incision at the root of the saxaul or thorn and carefully insert a watermelon seed into it. It is from it that openwork lashes will grow later, the watermelon root will grow together with the saxaul and will receive the same moisture as it\u003e. Big ripe watermelons will surely grow here in autumn. One must be careful when walking on such plantations. Any noise, even a loud voice, can crack a watermelon. This should not be allowed. A watermelon should crackle only from the touch of a sharp knife. This is the unshakable rule of desert nomads.
Why does man need sand? Sand is indispensable for construction. Sand is a filler for concrete, reinforced concrete, ballast for railways and roads, material for earth plates and dams. It turns out that we live among the sand, walk and drive on the sand too, but that's not all. If we look through the glass through the window, we will see everything that is behind it, but it turns out that the glass is made of pure quartz sand and the necessary additives. Heat-resistant chemical dishes, crystal products and much more are also cooked from quartz sand.
But that's not all. Since ancient times, people have admired the beauty of pearls. Pearls were considered an adornment only for the rich. The ancient Indians believed that pearls formed in a shell from the fact that dew drops fell into it. Similar legends were widespread in China and Russia. In reality, everything happens differently. A pearl starts with a grain of sand trapped between the inner surface of the shell and the mantle. The oyster coats this grain of pearl layer by layer. As a result, a shiny ball is formed over time. This is the gem.
Sand and people
And also people really love to travel, admire the famous sands.
And some people are attracted by the rally on the sand.
Sand creativity
Sand is a short-lived material, but it attracts people and makes them create.
The beauty at the festival\u003e enchants and delights everyone.
Now more and more people are addicted to\u003e.
And you can also visit the sand museums to listen to the sounds.
Sounds in the desert.
The song of the sands, the song of the sirens, luring travelers to certain death in a waterless desert, the bell ringing of monasteries buried in the abyss of sands.
This is how the English researcher R.A.Bagnould describes his impressions - the author of the first book about the singing sands, published in 1954. Nomads who heard these mysterious sounds considered them to be the voices of ghosts and demons living in the sand dunes. And although today it is known that acoustic vibrations arise as a result of the movement of layers of sand, it has not yet been possible to fully explain this phenomenon. There are two types of sounding sands - "humming" and "whistling", which differ in the frequency and duration of the emitted sound, as well as the conditions necessary for its occurrence.
The most common "sibilant" or "squeaky" sands, so named for their ability to emit short, less than a quarter of a second, high frequency sounds - from 500 to 2500 Hz. Walking along such sand, you can hear a slight whistling underfoot. The sound is musically pure and can contain five to six harmonic overtones. There are whistling sands on the coasts, rivers and lakes around the world. More rare and unique phenomenon is considered to be "humming" sands. You can hear them only deep in the desert near individual large dunes. Showered by avalanches, such sands emit a loud sound of low frequency (50-300 Hz), usually lasting a few seconds, but sometimes up to 15 minutes. Sound can reach such a force that it travels 10 kilometers, and is often accompanied by soil vibrations (seismic shocks), many times more intense than sound vibrations. Unlike whistles, the sound of humming dunes contains, in addition to the main frequency, many close frequencies. In this case, more than one harmonic of the fundamental tone is never encountered. For centuries, this "hum" has caused superstitious horror among the inhabitants of the desert, giving rise to a lot of legends and tales. So, in 1295, Marco Polo wrote about the evil spirits of the desert, who "at times fill the air with the sounds of all kinds of musical instruments, beat drums and clap their hands." The sound of humming sands sometimes resembles a drum roll, sometimes the sounds of a trumpet, harp, and even bells. Today it is often compared to the hum of telegraph wires or the propellers of a low-flying plane. More than 30 humming dunes are now known in the Americas, Africa, Asia, the Arabian Peninsula and Hawaii. But you don't have to travel to distant lands to hear the humming sands. You need to have a computer with a sound card and Internet access. "Songs of the Desert" is recorded at http: // www. yo. rim. or. jp / ~ smiwa / sound / badaja. html. The fact that whistling sands are found mainly on the coasts, and humming sands only deep in deserts, is apparently due to their different response to humidity. In order for the sand to "hum", at least several weeks of drought are necessary: \u200b\u200bthe grains of sand must be absolutely dry. Even at low atmospheric humidity, a thin film of water forms on their surface, which impedes sound, and five drops of water can silence a whole liter of humming sand. Whistling also occurs only in dry sand. However, for the best sound, periodic flushing of the whistling sand with water is simply necessary. Sometimes with its help it is even possible to "revive" the sand, which for some reason has lost its ability to make sounds. Perhaps this is due to the fact that water washes out pollution from the sand, and it itself becomes looser. In any case, the whistling sands rarely extend inland for more than 30 meters.
Currently, the number of sounding sands on our planet is rapidly decreasing. This is due to the heavy traffic on the coasts and deserts, the development of mass tourism, air and water pollution. We can say that the musical abilities of the sands serve as a natural indicator of the ecological state of the Earth. Protection of a unique natural phenomenon from complete destruction requires special measures. To this end, on November 17, 1994, in the Japanese city of Nima, the World Symposium on Singing Sands was convened. It discussed the tasks of preserving and reviving the sounding sands on the basis of international cooperation and a scientific approach to the problem. The center of the movement to protect the singing sands from destruction was the Japanese city of Nima. On March 3, 1991, the Sand Museum was opened there, where unique collections of sand from all over the world are collected. This museum is also famous for the fact that it houses the world's largest hourglass: five meters in height and a meter in diameter. For a whole year, a ton of sand is poured from the upper reservoir of the watch to the lower one. On the last day of every year, exactly at midnight, the locals carefully turn this giant sand calendar - and everything starts all over again.
There is an established opinion that it is quite easy to choose sand: if you ordered building sand, here you have both the raw material for concrete and the filling for the path. But this opinion is wrong. Since there are several types of sand that have their own distinctive characteristics, and are used when performing certain work.
Classification
So, according to the place of origin, sand is usually classified into the following types:
River sand
River sand is mined from the bottom of rivers. It is distinguished by its natural purity and good culverts. The size of grains of sand in river sand ranges from 0.3 to 0.5 mm.
This type is used for the preparation of concrete solutions, cement screeds, treatment filters, drainage structures. It is worth noting that when preparing a concrete mixture, this type of sand precipitates quickly, so the solution must be constantly mixed. The cost of river sand ranges from 600 to 800 rubles per 1 m 3.
Quarry sand
Quite logically, quarry sand is mined by an open method and includes impurities: dust particles, stones. The grains of open-pit sand are much smaller than that of river sand, ranging in size from 0.6 to 3.2 mm.
In its original untreated form, the building material can be used for trenching or as foundation sprinkling. Usually the leading manufacturers wash and sift the quarry sand. In this case, it can be used when performing plastering and finishing works, to create an asphalt concrete mixture, to form a screed.
Sea sand
This non-metallic mineral is extracted from the seabed using hydraulic shells. There are practically no foreign impurities in it, and salt participates in the purification.
This type of sand is considered the most demanded. It is used everywhere, from the creation of concrete structures to the formation of finely dispersed dry mixes. But, despite the unique characteristics of this building material, there is a shortage in it, since it cannot be mass produced.
Sometimes construction sand is considered a separate species. But, as a rule, it means both river and quarry sand. River sand can be of two colors - yellow and gray, and quarry - brown and yellow.
But it turns out that nature also exists black sandthat shines like metal. It can be found in different parts of the world. And this type of sand is formed as a result of geological processes.
This mineral is composed of dark colored heavy minerals and is formed by washing out light constituents. The main minerals are magnetite, ilmenite, hematite.
Such sands are characterized by high radioactivity - 50-300 micro-roentgens per hour, but sometimes this parameter can reach a thousand micro-roentgens per hour. Due to its high radioactivity, this mineral is not used in construction and economic activities.
Artificial sand
It should be noted that the above types of sand are natural, as they were formed by the natural destruction of rocks. But, there are also artificial sand, created by crushing marble, limestone, granite.
The most popular among artificial types of sand is quartz... It is made by grinding and dispersing the white quartz mineral until a homogeneous fraction is obtained. It differs from natural types of sand in that it does not contain impurities and has a homogeneous composition. These advantages make it possible to accurately calculate the parameters of a structure made on quartz sand.
Most often, when a person imagines summer, he has the following associations: sea, sun, beach and hot yellow sand. So soft, golden or orange, red, black, or maybe green? Colored and unique, they are located all over the world, and some of them are truly incredible.
Beaches of all colors of the rainbow
Picturesque and colorful sandy beaches can be found in many parts of the world. According to the Guinness Book of Records, the whitest sand in the world is found in Australia. Golden beaches can be found in Manduria (Italy). The individual color of each grain is influenced by the minerals, the composition of the rocks, plants and even animals that live in the area. The same beach may appear more yellow, gold, brown or bright orange depending on the time of day, sun and weather.
The most beautiful and unusual beaches
The pink sands of the beach on Harbor Island (Bahamas) look very unusual. Located on the eastern side of the island, they have this hue due to the red shells of single-celled marine animals mixed with white sand. The green Papakolea beach in Hawaii or the coast of Floreana Island (Galapagos Islands) looks very harmonious. If you carefully examine a handful of such sand, you can see a huge amount of glassy crystals of olive color, they make up most of the sand, as they are washed out of local rocks.
In Puerto Rico, on the island of Vieques, the red sand on the beach surprises with its beauty and singularity. A real hidden treasure of nature is Kaihalulu Beach on the island of Maui (Hawaii). Dark red sand can also be seen here. Local rocks are rich in iron, which is why such a rich shade. It is not easy to get here, as this picturesque place is extremely isolated and inaccessible.
What is sand?
Sand is a free-flowing granular material that covers the beaches, riverbeds and deserts of the world. It is made up of different materials that differ depending on the location. The most common component of sand is silica in the form of quartz, as well as rocks and minerals such as feldspar and mica. Thanks to the weathering processes (wind, rain, thawing, freezing), all these rocks and minerals are gradually crushed and turned into small grains.
Tropical islands such as Hawaiian do not have rich sources of quartz, so the sand is different in these places. It can be white due to the presence of calcium carbonate obtained from the shells and skeletons of marine organisms. Tropical beaches can also have black sand, which is composed of dark volcanic glass. Surprisingly little is known about the origin of sand in the world's largest deserts. Research shows that the Sahara Desert was once lush with vegetation before climate change turned it into a desert.
Such different sand
Why is sand so different in color in different parts of the world? Nature never ceases to amaze everyone with its diversity, including extremely colorful sandy beaches, painted with rainbow hues: green, red, orange, pink, purple, brown, golden yellow and white. And some beaches have black sand. So what is the reason for the difference? The answer lies in the depths of the geology of the entire coastline. Sand is fragments of rocks and minerals such as quartz and iron that range in size from 63 microns (one thousandth of a millimeter) to two millimeters.
Sand in terms of geology
The geology of the surrounding area greatly influences the composition and color of the sand. For example, on the coast, consisting of rock formed by volcanic eruptions (granites), the sand will be lighter. If a large part of the coast contains metamorphic rocks that have been folded and mixed with other rocks, which allowed them to increase the amount of oxides such as iron, then the shades will be much richer.
When various rocks break down into the grains that make up the sand on the beach, their color is mainly determined by the presence or absence of iron, a very common mineral on Earth. When iron minerals are exposed to air, they begin to oxidize and produce red, orange, or yellow sand. Sometimes the color depends not only on the geological rocks. It is influenced by organisms living in water. Some beaches are made up of tiny pieces of coral and skeletal remains of sea creatures such as molluscs, crustaceans and foraminifera, which give the sand a pearly white hue.
Beach creation and color
Beaches can form anywhere where the sea or ocean crashes into the mainland. For millennia, waves have eroded the coastline, creating flat spaces called beaches. These new expanses begin to accumulate sinking sediments from the surrounding highlands, as well as eroded, wave-tossed debris from the ocean floor. Coastal winds and storms are also involved in creating beaches. The color of the sand at a particular location usually reflects the surrounding landscape and the hues of the adjacent ocean floor.
Thanks to its unique geology, Hawaii has so many colorful beaches that you will not find anywhere else in the world. For example, the coal-black sand of Punaluu Beach is the result of volcanic activity. It includes crumbs of basalt and is considered the blackest in the world. The white sand of Hyams Beach has been named the whitest and cleanest in the world. It is so crushed that it looks like powdered sugar. Located on the Hawaiian island of Maui, Kaihalulu Beach is famous for being one of the few places in the world with iron-rich red sand.
Is a black sand beach rare or common?
The most unusual are the black sand beaches, which is simply the stunning result of volcanic activity near the coast. Black sand can be seen over quartz sand in regions of high terrestrial activity, on the slopes of volcanoes, and in areas where most rocks are dark in color and poor in silica. Most of them are rich in iron, and the weight of this sand is heavier than ordinary quartz. Why is the sand black? It can be composed of a number of different dark minerals of volcanic origin.
Locations with black sand beaches are often the source of deposits of gemstones such as garnets, rubies, sapphires, topazes and, of course, diamonds, which form in the vicinity of volcanoes and can erupt outward along with lava flows. Black sand beaches can be found in Argentina, South Pacific Islands, Tahiti, Philippines, California, Greece, Antilles, Hawaii.
The world is full of beautiful beaches and there is no doubt about it. And although most people would gladly agree to soak up the bright sun, lying on white or golden sand, you should still pay attention to other beaches, with sands of other colors of the rainbow.
