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What is the name of the mineral rock salt?

Stones and minerals Author Amazing in Stone Reading time 4 min Views 482 Published 10.10.2020/XNUMX/XNUMX

History

Halite, better known in mountain parlance as rock salt, has its etymological root in the Greek words hals and lithos, meaning salt and stone respectively. This is the result of the evaporation of salty seas and lakes during the geological periods of the Triassic, more than two hundred million years ago, and the Oligocene, thirty-three, twenty-three million years ago. It is called an evaporitic rock, as opposed to igneous rocks such as granite or metamorphic rocks such as gneiss. The deposits take the form of tangled crystals. It is transparent in its pure form, but often takes on a gray or ocher color when impurities such as clays are included. Although salt pans have been used by people since prehistoric times, their modern discoverer is Ernst Friedrich Glocker, who gave them the name “halites” in 1847.

Extraction, use, composition, properties

  1. The evaporation of sea water is carried out in salt pans (or salt marshes), as a result of which grains with a cubic, less often pyramidal shape are formed;
  2. Evaporation of brine;
  3. Leaf ash from which the minerals found in plants can be extracted, this method is used in environments with the least saline resources.

Using

The commercial use of halite gave rise to salt routes, a symbol of the significant role they played in the economic development of some regions. Thus, in the Sahel, desert nomads drove a caravan of camels, called Azalay in the Tuareg language, which transported the priceless stone more than a thousand kilometers from the Malian mines of Taoudeni to various markets, where they exchanged it mainly for slaves. The same trade was carried out in Tibet, where yak caravans led by nomads transported the mineral from the Himalayan peaks to the plains. It was then exchanged for grain and other important products. Later, Alexander the Great was the first to transport this precious material from the Himalayas to Europe. As evidence of the region’s immeasurable resources, the world’s second largest mine, located in Khewra, Pakistan, is still mined by hand.

Composition

It is a solid mineral whose main chemical component is sodium chloride (NaCl). It is found in a soft and very light evaporitic rock, also known as halite, which is brittle, salty and contains traces of oxygen, silica, fluorine, bromine, iron and iodine. In its pure form, this salt stone is colorless or white, durable and moist to the touch. Most often, inclusions of impurities such as calcium chloride or magnesium chloride make it stratified and give it different shades. The mineral can be gray or ocher in color, or can be much darker, black or brown, or even purple and blue. It is easily characterized by its salty taste, solubility and cubic shape, which distinguishes it from other crystals whose faces can form a pyramid.

physical properties

Chemical classification sodium chloride
Color colorless, gray, yellowish to reddish, brownish, black, blue, violet.
Streakness White
Brilliance glass
Transparency Transparent to translucent
Cleavage perfect by
Mohs hardness 2.5
Density 2.1
Defining Features fragility, hygroscopicity, highly soluble in water, salty taste.
Chemical composition NaCI
Crystal structure Cubic
Application Raw materials for the food and chemical industries

Origin

The mineral often occurs with other evaporites such as gypsum or anhydrite, and is less commonly accompanied by limestone, clay or dolomite. Deposits of halite, whether visible on the surface of the earth or hidden, characterized by the presence of salt springs, were already known in antiquity. The mineral may originally come from ancient seas that have retreated, but also from volcanic or plutonic rocks, which explains why brackish or saline waters are found in basins that have no connection with the sea.

Place of Birth

The thickness of the clusters can vary from one meter to more than three hundred meters. Sometimes they are not very dense salt marsh masses; they can look like large domes, and the largest of them extend for almost tens of kilometers, with a thickness of up to two kilometers. These structures rise above the ground, forming round shells that can be identified using special geophysical measurements.

The magical properties of halite

  • It restores the body’s chemical balance and replenishes essential minerals;
  • The mineral is especially useful for respiratory diseases that affect the lungs or sinuses;
  • It relieves headaches;
  • The stone is also useful for intestinal disorders and will help reduce water retention problems.

The mineral suits all zodiac signs.

Rock salt is a sedimentary mineral consisting primarily of sodium chloride. The composition of impurities depends on the characteristics of the deposits. Why is it rock salt, and not just, for example, sodium or chloride? This name reflects the state of the mineral and human attitude towards it. In their natural state, these are truly salty stones. Then, after processing, halite, as this salt is also called, becomes just the former salty powder. It is in this form that it is called table salt.

Main characteristics of rock salt

The mineral halite received its scientific name in Ancient Greece. The translation of this word is ambiguous, but its meaning is two concepts – sea and salt. The chemical formula of rock salt is simple – it is NaCl as the main substance and other elements as impurities. Pure rock salt contains 61% chlorine and 39% sodium.

In its pure form, this mineral can be:

  • transparent;
  • opaque but translucent;
  • colorless or white with signs of glassy luster.

However, pure NaCl is rare in nature. Its deposits can have shades of colors:

  • yellow and red (presence of iron oxide);
  • dark – from brown to black (admixtures of decomposed organic matter, for example, humus);
  • gray (clay impurities);
  • blue and lilac (presence of potassium chloride).

Halite is fragile, hygroscopic and, of course, has a salty taste. The mineral dissolves well in water at any temperature, but melts only at high temperatures – not lower than 800°C. When fire melts, it turns yellow.

The crystalline structure of rock salt is a dense cube, the nodes of which contain negative chlorine ions. The octahedral voids between the chlorine atoms are filled with positively charged sodium ions. The structure of the crystal lattice is an example of ideal order – in it, each chlorine atom is surrounded by six sodium atoms, and each sodium atom is adjacent to the same number of chlorine ions.

Ideal cubic crystals in some deposits are replaced by octahedral ones. In salt lakes, crusts and druses can form at the bottom.

Origin of salt deposits

Rock salt is a mineral of exogenous origin. Salt deposits were formed during sedimentary processes in a dry and hot climate. The origin of salt deposits is associated with the slow drying of drainless salt lakes, sea bays and shallow waters.

Halite salt is formed in small quantities during soil salinization and during volcanic activity. Soil salinization occurs in arid regions. This process can develop under natural or anthropogenic conditions. Natural salinization occurs where groundwater with high salinity comes close to the surface. This water evaporates, and a salt crust forms on the soil surface. In addition, the soil can also become salinized from above, for example, during sea surges or tsunamis. In this case, a large amount of salty seawater penetrates into the lower horizons of the soil, and then evaporates, and salt is deposited on the surface.

A person contaminates the soil with abundant watering in arid climates. In regions where the evaporation of water from the lower layers of the soil collectively exceeds the influx of water through precipitation, the soil is highly mineralized. If you water it, evaporation also increases. As a result, minerals deposited in different soil layers come to the surface. On such soil a salt crust forms, preventing any manifestation of life.

According to its origin, rock salt is divided into the following categories:

  • Self-sedimentary, which forms in evaporite basins, deposited as granular crusts and druses.
  • Stone, lying in large layers between different rocks.
  • Volcanic salt rock that is deposited in fumaroles, craters and lavas.
  • Salt marshes, representing salt crusts on the soil surface in an arid climate.

Geography of main deposits

Halite is concentrated mainly in deposits of the Permian period. This was approximately 250-300 million years ago. At that time, a dry and hot climate formed almost everywhere in Eurasia and North America. Ponds of salt water quickly dried up, and the salt layers were gradually covered by other sedimentary rocks.

On the territory of Russia, the largest deposits of halite are located in the Urals (Solikamskoye and Iletskoye deposits), in Eastern Siberia near Irkutsk (Usolye-Sibirskoye deposit). Halite is mined on an industrial scale in the lower reaches of the Volga, as well as on the banks of the famous salt lake Baskunchak.

Significant halite deposits are located:

  • in the Donetsk region (Artemovskoye field);
  • in Crimea (Sivash region);
  • in northern India in the state of Punjab;
  • in the USA – the states of New Mexico, Louisiana, Kansas, Utah;
  • in Iran – the Urmia field;
  • in Poland – the Bochnia and Wieliczka salt mines;
  • in Germany near Bernburg, where halite has blue and lilac shades;
  • large salt lakes are located in western South America.

Uses of rock salt

No matter how much people criticize the use of rock salt in the food industry and in everyday life, people cannot do without this “white death”. These are not just mineral compounds, although the complex composition of rock salt in some deposits is highly valued in medicine. Salt dissolved in water or food is an increase in the number of ions, that is, positively and negatively charged particles that activate all processes occurring in the body.

However, halite has also found its use in the chemical industry. For example, the production of hydrochloric acid, sodium peroxide and other compounds that are in demand in various consumer sectors cannot be done without NaCl. The use of halite, in addition to its consumption as food, provides more than 10 different production processes and final consumption.

This mineral is still the most popular and cheapest preservative, helping people live from one harvest to another, transport food over long distances, and stock up on food for future use. Salt’s function as a preservative continues to save people from starvation around the world.

Nowadays, sodium chloride has become one of the cheapest food products. And once upon a time there were salt riots. Convoys with this product moved under heavy security. This product was part of soldiers’ rations. Perhaps the consonance between the words soldier and salt is not accidental.

Salt extraction methods

How is halite mined nowadays? Modern mining is carried out using several methods.

  • Mass mining of large quantities of rock salt is carried out using the mining method, which involves extracting rock salt from sedimentary rocks. Since halite is a solid solid monolith, it must be softened at high temperature and under pressure. Special salt harvesters are used to raise salt to the surface.
  • The vacuum method involves boiling minerals from water with a high level of dissolved salt concentration. To obtain brine, a well is drilled to reach the rock salt deposit. After this, clean fresh water is pumped into the subsoil. The mineral quickly dissolves in it, forming a saturated solution. After this, the brine is pumped to the surface. This is usually how salt is extracted for food and medical needs, since the brine does not contain impurities of other rocks.
  • The lake method is based on the extraction of salt in open salt reservoirs. This method does not require the construction of boreholes or the construction of mines. However, the product obtained in this way requires careful cleaning, which affects the cost.
  • The method of evaporating seawater has been practiced for about 2 years. It was popular in countries with dry and hot climates. To obtain salt from sea water, no energy sources were needed here, since the sun itself coped well with the process of evaporation of water. However, this process was very slow, so when there was a large concentration of people thirsting for salt, special heating was used.

The opposite of evaporation is a method practiced in regions with cold climates. The fact is that fresh water freezes faster than salt water. For this reason, the early ice in the vessel, when melted, was practically fresh water. In the remaining water, the concentration of salt increases. So from sea water it was possible to simultaneously obtain fresh water and saturated brine. Salt was boiled out of the water of the late ice quickly and with less energy consumption.

Nowadays, NaCl is a product that has become familiar. The use of sodium chloride in food is in the nature of bringing its taste to the state of sea water. This is a need for all organisms living on land.

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