Clay as a mineral: description, types and properties. Cosmetic clay: cheap and cheerful. Unique natural remedy for face, hair and body

Clay is a product of weathering rocks, mainly feldspar and mica. earthquakes, strong winds, floods move rock layers, grind them to powder. Laid down in the cracks earth's crust they harden over millions of years.

Cambrian clays are primary, they have not been washed out for millions of years, although they have been weathered. Other clays are called secondary, it is a product of deposition. Secondary clays are found among sedimentary strata of all types - continental, including lacustrine, coastal-lagoonal and marine.

Lacustrine clays often have a monomineral kaolinite composition. Pure montmorillonite clays (bentonites) are usually formed as a result of alteration volcanic ash and pumice. In industry, 4 most important groups of clays are distinguished: coarse-ceramic, refractory and refractory, kaolins, adsorption and

highly dispersed montmorillonite.

The main chemical components of clay are secondary minerals of a simple composition: silicon dioxide (quartz, SiO3 30-70%), aluminum hydroxide (AlO3, 10-40%) and H2O (5-10%). TiO2, iron hydroxide (Fe20, FeO), MnO, MgO, CaO, K20, Na20 are present in clays.

In addition, in the process of weathering, secondary minerals of a more complex structure (aluminum and ferris silicates) are also formed. They are more highly dispersed than primary minerals. All secondary minerals of complex composition have a lamellar structure and contain chemically bound water. Because these minerals are essential integral part various clays, they received the name of clay, or clay, minerals (A.I. Boldyrev, 1974). With all the diversity clay materials they have common feature: they were formed during the chemical destruction of other minerals and therefore the size of their crystals is very small - only 1 ... 5 microns in diameter.

Made up of clay leading role play kaolinite, montmorillonite, hydromicas, spars, limestones, marbles. According to the predominance of the clay mineral, mineral types of clays are distinguished: kaolinite, montmorillonite, hydromicaceous, etc.

The minerals of the kaolinite group include kaolinite AL2Si2Os(OH4) and halloysite Al28i2Ol(OH4) x 2H-0, as well as some other minerals. Kaolinite clays contain approximately 20-25% silty particles (less than 0.001 mm), of which 5-10% are colloidal particles (less than 0.25 microns). The minerals of this group are quite common in many types of clays. Such clays have relatively low swelling and stickiness.

Bentonites are sedimentary rocks composed of minerals of the montmorillonite group. These minerals have a layered crystalline structure like that of graphite or talc, that is, they consist of the thinnest flakes that can slide over each other under mechanical action. Therefore, these minerals feel greasy to the touch. Between the scales there are cavities into which water molecules easily penetrate. Due to this, bentonite clays swell strongly in water and form a plastic dough.

Of the minerals of the montmorillonite group, the most common in clays are montmorillonite AL2Si40|9(OH2) x nH20, beidellite ALoSbOyfOH?) x nH20, and nontronite Fe2Si4 0|o(OH3) x nH20. Montmorri-lonite clays, in contrast to kaolinite clays, have high swelling capacity, stickiness, and cohesion.

For them very hallmark is a high degree of dispersion (up to 80% of particles are less than 0.001 mm, of which 40-45% are less than 0.25 microns).

Among the clay minerals great place belongs to the minerals of the hydromica group. This group includes hydromuscovite (illite) KAb[(Si, Al)4O|0](OH)2 x pH.0, hydrobiotite K(Mg, Fe)3[(Al, Si)40io](OH)2 x pH20 and vermiculite (Mg, Fe++, Fe+++)2[(Al, Si)4O|0](OH)2 x nH20.

In addition to clay materials, all clays contain one or another amount of impurities that strongly affect the properties of clays.

Quartz is one of the most common minerals on Earth, consisting of only one silicon dioxide - silica (Si02).

Feldspar is a mineral in which, along with silica, alumina is necessarily present - aluminum oxide (A120z), as well as an oxide of one of the metals such as sodium, potassium, calcium.

Mica is very easily split into the thinnest transparent plates. Mica contains silica, alumina and (often) compounds of iron, sodium, magnesium.

Most often, these impurity minerals make up the sand present in the clay. Less common in clay are grains of limestone, gypsum, and other rocks and minerals.

Different minerals affect the properties of clay in different ways. So, quartz reduces its plasticity, but increases strength.

Clay crystal lattice

Clay minerals vary in structure. Such important properties of clay as solubility, volatility, viscosity and other properties that characterize the stability of the compound are due to the energy of the crystal lattice. Clay refers to crystalline solids, i.e. it has a clear internal structure due to correct location particles in a strictly defined periodically repeating order. Particles in crystals (atoms, molecules or ions) are arranged regularly, forming the so-called spatial lattice of the crystal.

The crystal lattice of various clay minerals is built from the same elementary structural units, consisting of silicon and oxygen atoms, as well as aluminum, oxygen and hydrogen atoms. The composition of clay minerals may also include Fe, Mg, K, Mi, and others. Clay minerals have a layered structure and are classified as layered silicates. Layers of clay minerals consist of a combination of silicon-oxygen and oxygen-hydroxyaluminum compounds.

The elementary cell of the silicon-oxygen compound is a tetrahedron, four vertices of which are occupied by O2" anions, and a smaller Si cation is located in the center of this tetrahedron.

The tetrahedron (SiC>4)4 is the main structural unit not only of clay minerals, but also of all naturally occurring compounds of silicon with oxygen (AI Boldyrev, 1974).

The excess of negative charges of this unit cell can be neutralized by the addition of some cations or by the connection of several tetrahedra through the vertices, when the oxygen ion is simultaneously bound to two silicon ions. For clay, the most typical are compounds in which silicon-oxygen tetrahedra are connected in layers (or sheets) of a cyclic structure. In such a layer, there are five oxygen ions for every two silicon ions, which corresponds to the formula (Si20s)2

Silicon-oxygen tetrahedral layers can combine with a layer of oxygen-alumina-hydroxyl atoms, which form octahedrons. In them, the aluminum ion is surrounded by oxygen atoms and hydroxide ions. Aluminum hydroxyl octahedrons are connected in the same way as silicon-oxygen tetrahedra - in octahedral networks or layers. They can be constructed by analogy with the mineral gibbsite Al(OH)3 or brucite Mg(OH)2.

Silicon-oxygen and oxygen-hydroxide-aluminum networks form the so-called tetrahedral-octahedral layers and packages. When the tetrahedral and octahedral layers are connected, the 0?' ions of the tetrahedral layer, located at the vertices of the tetrahedra, become common to both layers, i.e., the 0? ions will serve as a kind of "bridge" between the Si4~ ions of one layer and the ions Al3+ of another layer. Such a structure is the most stable, since the number of positive charges Si4+ and AC+ in this structure is equal to the number of negative charges 0? and he".

The minerals of the kaolinite group have a two-layer fistal lattice, the packets of which are formed from two connected through common atoms oxygen layers: a layer of silicon-oxygen tetrahedra and an aluminum-hydroxyl layer having a dioctahedral structure. Such two-layer packets alternate in the crystal at intervals, giving it a lamellar structure. Kaolinite is not able to absorb water into the spaces between the packages and therefore does not have the ability to swell.

Minerals of the montmorillonite group are divided into two groups according to their crystal chemical properties:

Dioctahedral (montmorillonite, nontronite, beidellite);

Trioctahedral (saponite, hectorite).

Montmorillonite is a three-layer mineral. Its packets consist of an octahedral layer (dio-octahedral structure), which is enclosed between two tetrahedral layers.

The composition of these layers is not constant due to isomorphic substitutions. Silicon of tetrahedra can also be partially replaced by aluminum and iron, and in addition to aluminum ions, magnesium ions can be present in octahedrons. Unlike kaolinite, interpacket distances of montmorillonite can vary. These distances vary depending on the amount of water between the packages. Because of this, montmorillonite has a high swelling capacity.

Hydromica minerals include hydromuscovite (illite), hydrobiotite, vermiculite, and other hydrated micas. The absorption capacity of hydromicas is several times higher than that of kaolinite, but 2-3 times less than that of montmorillonite.

The structure of illite is similar to that of montmorillonite, with the only difference being that there are numerous isomorphic substitutions in its crystal lattice. Thus, the Al3+ ion in the octahedral layers is replaced by the Fe3+ ion and the Mgα+ ion, and two aluminum ions are replaced by three magnesium ions with the replacement of octahedral voids. In illite, two aluminum ions in octahedrons are often replaced by two magnesium ions, while excess negative charges are compensated by potassium ions, which are located in the interpacket gaps.

Aluminosilicates - zeolites - have "molecular sieves" used as catalysts in the petrochemical industry to produce high-octane gasolines. Zeolites are the best adsorbents for radioactive waste nuclear power plants. They have proven themselves excellently in removing radionuclides from the body of "liquidators", as well as farm animals living in the contaminated area. Zeolites are vital for animals. Having eaten plenty of natural zeolites, the animals got healthier: they gained better weight, and among the calves the mortality decreased. This is explained by the fact that zeolites are able to absorb harmful substances and supply the missing components to the body.

The most important physicochemical and water-physical properties of clay - absorption capacity, hydrophilicity, cohesion, stickiness, reaction of the medium - are directly dependent on the mineralogical composition.

Free and bound water in clay

Water molecules themselves are neutral. However, one has only to place dipole water molecules in an external electric field, as the dipole character of these molecules immediately begins to manifest itself.

Hydration of hydrophilic colloids is also determined by electrostatic forces, i.e. due to electric charges arising from ionization. Shells are formed on the surface of colloidal clay particles, which consist of water dipoles oriented, depending on the type of charge, with their positive or negative ends.

Thus, in hydrophilic colloids, i.e., in clay solutions, some part of the water is firmly bound to colloidal particles, while the other part plays the role of a medium in which colloidal micelles are located.

The properties of bound water differ sharply from those of free water. In terms of the degree of structure ordering, bound water approaches the properties solid body and has a higher density than free water. Hydration shells of macromolecular compounds do not have dissolving properties; therefore, a macromolecular substance dissolves only in free water. bound water when the clay solution is cooled, it does not freeze, while free water is subject to freezing.

Metabolism in clay

Often clays are under a layer of sand, soil. When minerals and organic residues are washed out of the soil, they fall onto the clay substrate. The most intensive penetration occurs in top layer clay 10-15 cm thick. In the Orenburg region, a deposit of Miocene sub-coal clay has been explored and is being used (N.P. Toropova et al., 2000).

Clay is an excellent "exchange point" of mineral water ions. At the same time, the composition of the clay big influence provide natural mineral water. So, if sulfate-calcium (or magnesium) The groundwater migrate among clay rocks marine origin, usually containing exchangeable sodium, then the reactions proceed:

clay = 2Na+ + Ca++ + SO4<-»2Na+ + SO4 + глина = Са++

clay = 2Na+ + Mg++ + SO4<->2Na+ + SO4 + clay = Mg++

The symbol "clay=Ca++" denotes clay containing exchangeable calcium (or other exchangeable cation). This is how the exchange of cations occurs, the amount of the anion (SO4 ~) does not change.

Gradually, all exchangeable sodium passes from clays into solution. Water from sulfate calcium (magnesium) turns into sulfate sodium, and the absorbing complex from a typical marine - sodium becomes typically continental - calcium-magnesium (A.I. Perelman, 1982).

The clay fraction of soils and rocks contains two categories of ions: some easily pass into solution and are able to participate in reactions - these are exchange cations and anions; others are firmly fixed in the nodes of crystal lattices and can pass into solution only as a result of the destruction of minerals during long-term weathering processes.

The impurities included in the clay determine its color, consistency, special plasticity or stone hardness. There are up to 40 types of clays used in the faience and porcelain industries, pharmacology, construction, perfumery (the main part of the powder), chemistry, and the food industry. Clay is white, blue, gray, red, brown, green, black. Sometimes there are chocolate or dirty black clays.

The colors of clay are determined by the large amount of salts present in them:

Red color - potassium, iron;

Greenish - copper, ferrous iron;

Blue - cobalt, cadmium;

Dark brown and black - carbon, iron;

Yellow - sodium, ferric iron, sulfur and its salts.

The most active is blue, green and black clay. Kaolinite is well studied - the basis for porcelain products, it is white. Refractory clays are mostly kaolin, they are plastic, but they have little iron.

We continue to move into the cosmic unknown. The world is looking more and more like futuristic fiction. Therefore, the essentially unnatural return to simple, natural materials seems so natural.

Another source of the modern desire for naturalness is the permanent fear of ecological collapse. Environmentally friendly design is in demand today more than ever. It is today that clay is beginning to be associated with value, despite the stable, directly opposite historical connotations. Contemporary design embraces clay, enthusiastically discovering its incredible decorative and practical potential.

Clay in construction

Clay as a material in a modern interior has a very wide application due to its plasticity. What other material can be equally used both in bulky construction and in the manufacture of the finest handicrafts?

Clay, different in composition and properties, can be used almost everywhere today. So, along with the traditional clay one! - brick, adobe blocks are very popular as a building material. Consisting of clay, sand and organic fillers, they have both extremely low cost and excellent technical characteristics.

Although the modern technology for making adobe blocks differs from the traditional one: instead of straw, as a rule, sawdust is used, and the blocks themselves are not made manually, but mechanically, nevertheless, this material continues to retain the charm of ancient times.

Adobe blocks are actively used in construction today, and houses made from them show themselves in the best way, both in terms of technical criteria and aesthetically.

What you need to know to use clay

It is useful to know that in order to use clay independently, as a building or decorative material, to obtain a satisfactory, high-quality result, it is extremely important to be able to select the composition of the clay. This becomes more obvious if you know, for example, that the building mixtures themselves sometimes contain several types of clay at once, which tells them their qualities.

The amazing possibilities of clay

Clay as a material has a truly inexhaustible application possibilities. Known to man since ancient times of his formation, it still remains relevant. Like thousands of years ago, clay serves our most diverse needs, albeit in a different form than before: instead of unfired dishes, today we have at our disposal both universal faience and the finest porcelain; instead of adobe floors - a myriad of slabs and tiles - and so on.

Today, on the basis of clay, wall plasters, building mixtures, roofing and cladding materials, stucco moldings, sculptures, dishes, decorative items and much more are made. Despite the spread of innovative materials, clay firmly holds its traditional positions, and even penetrates into the camp of a competitor, constantly discovering new opportunities for its actualization.

Walls

Clay plasters are gaining more and more popularity today. The living surface of walls plastered using this material is not only very attractive, but also has many useful properties due to its naturalness and environmental friendliness.
Clay plaster is a hypoallergenic material that acts like a filter. It is able to absorb excess moisture, which contributes to the regulation of the microclimate inside the house. It is more than affordable. It is easy to apply. It has excellent protective characteristics and is resistant to microcracks, which prevents its destruction.

Floor

To date, there are a number of technologically different ways of arranging clay. At the same time, the composition and basic properties of these floors are almost identical.

The clay floor is poured or lined with a mixture of clay, sand, straw, gravel or other additives. As a result, the floor acquires a smooth, wear-resistant surface that is unique in its properties and appearance. Such floors have antiseptic and antistatic qualities. They contribute to maintaining an optimal balance of humidity, are able to contain and even neutralize unpleasant odors. In addition, they have the ability to retain heat: heating up during the day, they gradually release it at night.

It is also important that the surface of the clay floor does not require special maintenance and is easily repaired if necessary.

Facing

Facing exterior walls with clay is not an easy task: clay absorbs and releases water well when wet and heated, which leads to cracking. This requires the use of special technologies in the processing of the finished coating and the production of facing materials. As such, clay can be used in the form of ceramic outdoor tiles and plaster mixes.

Walls made of adobe are also not very moisture resistant, so they need additional plastering. Lime is traditionally used for this purpose, compensating for the natural lack of clay blocks and imparting a special charm to the building.

Roof

Traditional ceramic tiles are made by simply firing clay. Despite the simple technology, which has not changed since ancient times, such tiles can serve for many decades, sometimes without even needing repair. Manufacturers, as a rule, give a guarantee for their products up to 30 years.

Such tiles are not afraid of temperature changes, overdrying from direct sunlight, and even open fire and acid rain. The clay roof cools and heats up very slowly, which provides a special comfortable climate inside.

When choosing a tile, it is recommended to pay attention to the fact that the pores on its surface must be closed: the more “porous” the tile, the higher its ability to retain and absorb moisture, which can eventually lead to its destruction. In addition, the tendency to absorb a large amount of moisture significantly reduces the frost resistance of clay tiles.

Pottery

Despite the huge number of newfangled materials for making dishes, clay does not lose its position. Products made of ceramics, porcelain, terracotta and faience are still common and in demand.

Ceramic cookware does not emit harmful substances when heated. There is no scale in it. It is chemically inert - in a word, ceramics is almost an ideal version of dishes used in our everyday life. Terracotta is made from special red varieties of clay. After firing, it acquires a characteristic texture, while it can be both coarse-grained and fine. The color of terracotta varies from red-brown to creamy flesh.

Today, terracotta is used to make dishes, which was not done before: there was an idea that terracotta did not like water. The development of terracotta production technology has changed the situation, and now many manufacturers have turned to this material in search of new interesting solutions.

home spa

Clay has a very unusual use in modern life. Since the same ancient times, clay has established itself not only as a building or decorative material, but also as a cosmetic product.

Clay well tones, disinfects, whitens the skin. Great for making hair masks, as it contains a large amount of silicon, which promotes the growth and strengthening of the hair follicle.

Although today clay, by a strange coincidence, as a building or decorative material is perceived by us with a slight touch of exoticism or even social disorder, nevertheless, the global craze is changing this state of affairs more and more actively.

Every year projects and ways of using clay become bolder and more interesting. So it is quite possible to expect that after some time the appearance of our dwellings and cities can change significantly, including thanks to clay.

Cosmetic clay since ancient times has the status of an excellent and effective tool in the care of the skin of the face and body. Cleopatra herself regularly used it to preserve youth and beauty of the skin.

The beneficial effect of mineral clay was widely used not only in cosmetology, its properties were also valued in medicine. Pharaonic doctors used it as an excellent remedy with anti-inflammatory and antiseptic effects. In addition, it was included in the composition during mummification. Ancient healers on its basis made various kinds of rubbing, medicinal ointments and pastes. Cosmetic clay was also used for internal use, if it was necessary to achieve an absorbent effect. With its help, they got rid of bacteria and removed toxins from the body. Also, natural mineral clay was used for serious poisoning, muscle pain, epidemics.

Modern application in medicine and cosmetology.
Cosmetic clay is widely used in the field of cosmetology; it is usually included in various face masks that have a cleansing and drying effect. Clay has a wonderful property, like a sponge, it absorbs excess secretions of the sebaceous and sweat glands. In addition to cleansing qualities, it relieves inflammation and redness, and also relieves the skin of peeling. Especially clay-based masks are effective for oily, combination and dry skin. It should also be noted the ability of clay to enhance the bactericidal properties of certain substances, due to this, in fact, clay is included in the compositions of anti-inflammatory ointments and masks.

Types of cosmetic clays.
In general, there are several types of clay in nature, and all of them not only differ in color (due to different mineral composition, depending on the place of origin), but also have different properties, which is why they are used in cosmetology and medicine to solve different problems. Clay can be white, blue, green, red, yellow, gray, black and blue. You can buy natural cosmetic clay in almost any pharmacy or cosmetics store.

It should be remembered that when using cosmetic clay, it is necessary to mix their types or dilute with the addition of other components only in earthenware, but not in iron. Since cosmetic clay loves light, it is important to expose it to the sun.

White clay (Anapskaya).
The most commonly used of all types of cosmetic clay is white or kaolin, it is added to masks, ointments, diarrhea remedies. Often used to treat skin diseases, gynecological diseases, diseases of the musculoskeletal system. Also, white clay perfectly removes toxins.

This type has the most effective effect on oily (absorbs excess secretions of the sebaceous glands), mixed and problematic skin of the face, perfectly cleansing it, drying pimples (acne) and inflammation, narrowing pores, and also providing a lifting effect. But it is contraindicated to use in the presence of rosacea. It should be noted that this type of cosmetic clay has the property of whitening the skin. It also helps women to correct the oval of the face, to make it more even. Due to its antiseptic properties, white clay is added to various bactericidal and anti-inflammatory facial products. The systematic use of white clay increases the elasticity of the skin, makes it velvety, improves complexion.

The use of this type of clay is also useful for hair. Masks based on it make hair thicker, manageable and eliminate dandruff. The effect will be noticeable after a week or two weeks of use.

Blue clay (Cambrian, Valdai).
It contains a huge amount of salts and trace elements that are necessary for the beauty and youth of our skin. Thanks to its stimulating effect, blue cosmetic clay gives a pronounced rejuvenating effect, it is especially effective for oily skin. Regular use of blue clay is the prevention of acne, due to its disinfectant and astringent action, it dries up small inflammations and pimples, and also effectively smoothes mimic wrinkles.

In addition to the cleansing action, this type of cosmetic clay nourishes the skin at a deep level, supplying the skin cells with the necessary substances and energy of natural compounds, stimulating regeneration processes in the tissues of the epidermis, which helps to accelerate the healing process of wounds and damage to the skin. Cosmetic products based on blue clay activate blood circulation processes and accelerate metabolic processes in skin cells, restoring firmness, elasticity and healthy appearance to the skin. It is also worth noting that this clay has a slight lightening effect on freckles and age spots.

The use of blue clay for hair, due to the presence of silicon in its composition, activates hair growth, and also helps to eliminate dandruff.

Masks based on it are also effective for the legs in order to improve blood microcirculation, reduce swelling and heaviness in the legs. In addition, such products can help cope with cellulite, sweating, eliminate unpleasant odors, and also prevent fungal and bacterial diseases.

Green clay.
The green color of this type of clay is due to the content of iron oxide in it. Most often used in cosmetology, it is added to the composition of masks, wraps and compresses. The composition of the clay, rich in microelements, helps to restore the water balance of the skin, and also provides excellent absorbent properties. The use of green clay cleanses and softens the skin, eliminates inflammation and irritation, smoothes wrinkles, and also has a drying effect. Often it is recommended to improve capillary circulation, as well as general skin rejuvenation. Masks based on it perfectly cleanse the pores and get rid of oily sheen. This type of clay can be combined with other types.

It should also be noted that this clay is recommended for bathing in order to relieve stress, tension, fatigue and irritation. This recommendation is due to the property of green clay to take away the negative energy accumulated during the day.

Red clay.
The color is due to the presence of copper and iron oxide in the composition. This type of cosmetic clay is recommended in the care of dry, dehydrated, and sensitive skin, which is prone to allergic reactions. Products based on red clay, in particular masks, improve blood circulation in the tissues of the epidermis, help soften and moisturize the skin, perfectly exfoliate the dead layer of cells, eliminate itching, irritation and redness on the face. In addition, they perfectly eliminate the signs of skin peeling. Also, this type of clay can help in the care of aging skin, as it improves tissue oxygenation. It is often prescribed for iron deficiency in the body. Red clay is often combined with white.

Red clay is also effective in hair care, products based on it help nourish hair follicles, strengthen weak and brittle hair, and also eliminate oily seborrhea.

Pink clay.
Pink cosmetic clay is recommended for all skin types. It is obtained by mixing red clay and kaolin, which allows it to have the effect inherent in both types of clay. Its use promotes skin rejuvenation, smoothing wrinkles and tightening the contour of the face. The use of masks based on it cleanses, nourishes and softens the skin, restoring elasticity and providing a refreshing and regenerating effect. Baths based on pink clay promote deep hydration of the skin, have a tonic effect, improving metabolic processes in tissues.

Yellow clay.
This type of clay contains a huge amount of iron and potassium, which improves the oxygen supply of tissues, and also determines its ability to remove toxins in cases of various inflammatory processes. Masks based on yellow clay have a tonic effect, improving complexion. It is recommended for use in the care of oily, mixed, aging and dull skin.

Due to the rare chemical composition, experts recommend it for the correction of various cosmetic flaws, as well as a prophylactic against many skin diseases. Yellow clay has the ability to absorb the waste products of the body, in addition, it has a detrimental effect on pathogenic bacteria. Baths based on it perfectly relieve fatigue, accelerate metabolic processes in tissues, improving the appearance of the skin.

Gray clay.
This type of cosmetic clay is mined in the sea at great depths. Its use gives a pronounced moisturizing and tonic effect. In most cases, it is recommended in the care of problematic, dry and dehydrated skin. Gray clay promotes deep detoxification of the skin and the body as a whole.

Masks based on gray clay effectively cleanse and deeply nourish the skin, tighten pores, due to its antiseptic properties, have a healing effect on acne and boils, and also have a pronounced rejuvenating effect.

The use of clay in the composition of hair products helps to strengthen the hair, prevent their fragility and loss, and is also the prevention of peeling of the skin.

Baths made of gray clay perfectly soften the rough skin of the hands and feet, heal small cracks and damage to the skin.

Black clay (Dead Sea).
The composition of this type of clay contains iron, strontium, magnesium, quartz and calcium. Means based on it perfectly cleanse the skin of impurities and toxins, narrow pores. Best suited for combination and oily skin, as well as for normal skin types.

Mud therapy with the use of black clay improves blood circulation and lymph circulation, as well as metabolic processes. In addition to this, procedures based on it stimulate tissue respiration, regeneration processes, and promote the resorption of inflammation processes. Black clay masks are an excellent means of moisturizing and toning the skin.

Black clay body wraps have an excellent volumizing effect as they promote fat burning.

Blue clay.
Masks based on blue clay have a cleansing, whitening and softening effect, help tighten pores, and also have a pronounced rejuvenating effect. Baths with the use of this type of clay have an antiseptic effect, accelerate the regeneration of skin cells.

In addition, it has a stimulating effect on metabolic processes in cells, increasing blood circulation and providing an anti-stress effect. Blue clay is recommended for use for any skin.

Clay- a plastic natural material used in construction, folk crafts, treatment and improvement of the body and in other areas of human life. It is this widespread use that determines certain qualities and properties of clay. And the properties of clay are largely influenced by its composition.

Clay application

Clay is very affordable, and its benefits are invaluable, and therefore it has been used by people since very ancient times. There are many references to this wonderful material in the history textbooks of all countries of the world.

Construction. Currently, clay is used as a material for making red bricks. Clay of a certain composition is molded and fired according to a certain technology, obtaining a durable and inexpensive ingot - a brick. Buildings and structures are already being built from bricks. In some countries and regions, clay is still used to build dwellings - mud huts, and clay is widely used in the construction of brick ovens, where clay serves as a binder (as cement). The same clay is also used for plastering ovens.

The medicine. Wellness and traditional medicine uses clay in the form of mud baths and masks. The whole point is to nourish the surface of the skin with beneficial clay elements. Of course, not all clay will do here.

Souvenirs and tableware. I combine two large areas into one, since many items of dishes are only souvenirs. Plates, pots, jugs and vases are in abundance in modern stores. Not a single fair is complete without the sale of clay souvenirs - smoke toys, whistles, tablets, key chains and much more. We will try to mold a lot on our own.

Clay may be included in composition of other materials. Chasovoyarskaya clay of fine grinding, for example, is an element of artistic paints (gouache), sauce, pastels and sanguine. Read about it in the articles "Help the artist".

clay properties

Color. Clay of various compositions has many shades. Clay is called by its colors: red, blue, white... True, during drying and further firing, the color can completely change. This is worth paying attention to when working with clay.

Plastic. It was the ability to deform and retain the shape given to it that allowed a person to find the use of clay in his life. Here it is worth noting that it all depends on the consistency - the ratio of the amount of water, clay and sand. Different jobs require different compositions. So, for modeling sand may be generally redundant.

Hygroscopicity allows clay to absorb water, changing its properties of viscosity and plasticity. But after firing, clay products acquire water resistance, strength and lightness. The development of technology made it possible to obtain faience and porcelain, indispensable in the modern world.

fire resistance. A property used more in construction than in art crafts, except for the firing of products. The firing technology is different for a particular clay composition. The property of clay shrinkage or compressibility is closely related to drying and firing - a change in mass and size due to the removal of part of the water from the composition.

Clay composition

The properties of clay determines its chemical composition. Different types of clay have different chemical compositions. So, for example, red clay contains a lot of iron oxides. Clay basically contains certain substances - clay minerals - which are formed during various natural phenomena. The format of the article does not include consideration of the chemical properties and composition of the clay, so I will not go into details.

The composition of clay suitable for use in folk crafts, as already mentioned, is determined by three important elements: clay minerals, water and sand.

The proportions of these elements can be changed, although it is much easier to add than to remove. So, for example, dry clay can be quickly dissolved, however, it is not at all easy to make clay liquid like sour cream suitable for modeling. Sand is very easy to add, but removing it from clay is not a trivial task.

Distinguish "skinny" and "fat" clay. The fat content scale determines the coefficient of plasticity, and the binding properties of clay allow you to adjust the fat content by mixing it with other natural materials, such as sand. Skinny clay has less plasticity, its binding strength is weaker, but it shrinks less during drying and firing.

Clay deposits are found in various states throughout the world. This ensured the use of it by artisans of different nationalities, and served as the emergence of such a variety of products and technologies.

Artisans have learned to control the behavior and condition of clay through various additives to the composition. So you can thin the clay, elutriate, give it greater fire resistance, reduce shrinkage. As a result of such manipulations, an experienced master will be able to end up with a high-quality, highly artistic product.

Clay is a mineral and is a sedimentary fine-grained rock. In the dry state, it is dusty, and when moistened, it becomes plastic and can increase in size.

Description

The composition of the material contains one or more minerals of the kaolinite group. The basis may be a mineral of the montmorillonite group and other layered aluminosilicates, which are also called clay minerals. May contain carbonate and sand particles.

The rock-forming mineral is kaolinite, which consists of silicon oxide in the amount of 47%, aluminum oxide - 39%, and water - 14%. A significant part of the chemical composition of yellow clay is Al 2 O 3 and SiO 2. The material can have the following colors:

• green;
• blue;
• Brown;
• the black;
• lilac.

The color is due to impurities of ions, which are chromophores.

Main types

Clay is a mineral that has several types. Each of them has its own area of ​​use. If the plasticity number reaches 0.27, then the material is called light. When this parameter exceeds the mentioned figure, then the clay is heavy. The clay most commonly mined and marketed consists of kaolin, which is used in the pulp and paper industry and in the manufacture of refractory products, as well as porcelain.

Clay is a mineral, which is also represented by a construction variety, as well as shale. This material is used for the manufacture of refractory bricks, and also forms the basis of heat-resistant products. Among the species, bentonite occupies an important place. It is formed by the chemical breakdown of volcanic ash. In water, this variety swells and increases in volume several times. It is used in well drilling and in the production of drilling fluids.

Clay is a mineral, which is also represented by a fuller variety, which is valued for its bleaching properties when refining petroleum products. Filters are made from this type of clay, which are used in the purification of mineral and vegetable oils.

Another variety is lump clay, which is called pottery. It has found its application in the manufacture of dishes. Shale is an important raw material that, together with limestone, is used in the production of Portland cement. The most common in nature are:

• sandstone clay;
• white clay, which is kaolin;
• red clay.

Grades are used for the production of refractory products, as well as faience and porcelain.

Basic properties

Clay is a mineral that has a number of properties, among them are:

• air and fire shrinkage;
• plastic;
• sintering;
• fire resistance;
• viscosity;
• color of ceramic shard;
• porosity;
• shrinkage;
• dispersion;
• swelling.

Clay is the most stable waterproofing agent that does not allow moisture to pass through, which is one of the important qualities. Clay soil is resilient. It is developed in wastelands and wastelands. The development of root vegetation in clay deposits is impossible.

To preserve the quality of groundwater, the water impermeability of the material is useful. Most of the quality artesian springs lie between the clay layers.

Specifications and additional features

Now you know if clay is a mineral. However, this is not all that should be known about this rock. It is also important to familiarize yourself with the main characteristics, for example, the specific and volumetric weight of ground clay, which is 1400 kg / m 3. Chamotte clay is characterized by an indicator of 1800 kg / m 3.

When the clay is in the form of a dry powder, its volume and specific gravity is 900 kg/m 3 . The density of wet clay is also important, which varies from 1600 to 1820 kg / m 3. For dry, this figure is approximately equal to 100 kg / m 3. Dry raw materials have a thermal conductivity that reaches 0.3 W / (m * K). For a material in a wet state, this parameter is 3.0 W / (m * K).

Symbol

The symbol for clay should be of interest to you if you are studying it. When there are sand impurities in the material, it is indicated by dashes and dots. If there are boulders in the clay, then circles are added to the strokes. Shales have the same designation as layered clay, these are long strokes, densely spaced and drawn in the direction of the layers.

sand and clay

Sand and clay are the minerals that are the most common. They are formed during the destruction of rocks like granite. Under the action of water, sun and wind, granite is destroyed, this contributes to the formation of clay and sand. They differ in color from each other: sand is more often yellow, sometimes gray, while clay is white or brown.

Sand consists of individual particles of different sizes. The grains are not attached to each other. Therefore, the sand is free-flowing. Clay consists of small particles, similar to scales, well bonded to each other. Sand is a sedimentary rock or may be an artificial material from rock grains. Usually it consists of almost pure mineral quartz, the substance is silicon dioxide.

Natural material has grains with sizes within 5 mm in diameter. The minimum value is 0.16 mm. Sand can be classified according to the conditions of accumulation. With this in mind, the material is divided into the following types:

• alluvial;
• deluvial;
• nautical;
• lacustrine;
• eolian.

If the sand appeared as a result of the activity of reservoirs, then it has a more rounded particle shape.

Properties of granite

Sand, clay, granite, limestone are minerals. If we consider granite in more detail, then it is a magmatic platonic rock of acidic composition. At the core are:

• potassium feldspar;
• plagioclase;
• quartz;
• biotite;
• muscovite

Granite is common in the continental crust. Its density reaches 2600 kg / m³, while the compressive strength is 300 MPa. The material begins to melt at 1215 °C. In the presence of pressure and water, the melting point drops to 650 °C.

Granite is the most important rock of the earth's crust, it is widespread and makes up most of all components. Among the varieties of granites, alaskite and plagiogranite can be distinguished. The latter has a light gray color with a sharp predominance of plagioclase. Alaske is a pink granite with a sharp predominance of potassium-sodium feldspar.

Limestone properties

Considering the table of minerals: sand, clay, granite, limestone, you can focus on the latter. It is a sedimentary rock of organic or chemogenic origin. The basis is most often calcium carbonate in the form of crystals of different sizes.

Limestone consists of shells of marine animals and debris. The density of the material is 2.6 g / cm 3, its frost resistance is F150. The compressive strength is equivalent to 35 MPa, while the loss of strength in wet conditions reaches 14%. The porosity of the material is 25%.

Finally

Clay is a sedimentary rock that, when combined with water, begins to soak and separate into separate particles. As a result, a suspension or plastic mass is formed. Clay dough is plastic, and in its raw form it can take any shape. After drying, the material retains it, but decreases in volume. Plastic clays are also called oily, because they seem to be just like that to the touch. If the plasticity is low, then the material is called lean. Bricks from it quickly crumble and have poor strength.

The rock is sticky and has a binding ability. It is saturated with a certain volume of water, and after that it no longer allows liquid to pass through, which indicates water resistance. Clay has a covering power, so earlier it was widely used for whitewashing the walls of houses and stoves. Among the properties, sorption should be highlighted. This is expressed in the ability to absorb substances dissolved in water. This characteristic allows the use of clay for the purification of vegetable fats and refined products.