What is mother of pearl? Properties, extraction, application and price of mother-of-pearl. Copying natural processes helped create artificial mother-of-pearl The future of mother-of-pearl: military nanotechnology

Willem Kalf, Still Life with Holbein's Chalice, Nautilus Goblet and Fruit Plate, 1678

Chinese scientists have described a method for obtaining artificial mother-of-pearl that does not differ from natural. The technology can also be used to synthesize other complex metamaterials that combine polymeric and mineral components. The authors write about this in an article published by the journal Science.

Mother-of-pearl is a natural composite material of complex structure, which some types of mollusks deposit on the inner wall of the shell. It is formed by orthorhombic crystals of calcium carbonate - aragonite. Hexagonal plates of this mineral with a diameter of about 10-20 microns and a thickness of about 5 microns are laid in parallel overlapping layers, which are laid with protein and polysaccharide biopolymers, including chitin and fibroin.

This combination gives mother-of-pearl a number of valuable characteristics that are very interesting for practical use: strength, elasticity, resistance to cracking. There are various approaches to obtaining artificial mother-of-pearl: through layer-by-layer build-up, self-assembly, and Freeze-casting. However, Shu-Hong Yu and his colleagues at the University of Science and Technology of China note that none of these complex technologies produce a material that can match natural mother-of-pearl, and “does not use the strategy that living organisms use.”

The first successful attempt to obtain mother-of-pearl by simulating the natural process of mineralization was made by Cambridge researchers back in 2012. Scientists deposited a thin layer of biopolymers on the surface of a glass substrate, formed a porous structure in them, and then immersed them in a solution containing new polymers, as well as calcium and magnesium salts in the quantities that they are found in natural mother-of-pearl. The process was repeated over and over again to build up new layers until high-quality samples of artificial mother-of-pearl, "identical to natural", were obtained.

Chinese scientists led by Shu-Hong Yu simplified this approach based on the mineralization of polymer matrix layers. Using freezing - anisotropic formation of crystals during cooling of a chitosan solution, the authors obtained a layered structure, which, under the influence of acetic acid, was acetylated to form a stable chitin matrix. A solution of calcium bicarbonate was pumped through it in the presence of magnesium, which was precipitated by mineral layers between the layers of chitin. Finally, fibroin protein polymers were added to the material and pressed.

Having studied the resulting metamaterial, scientists confirmed its closeness to natural mother-of-pearl at different levels of the structure. Calcium carbonate formed crystals of aragonite somewhat larger than natural ones, which made the mother-of-pearl slightly less hard. However, in general, such a material retained all the useful properties of mother-of-pearl, including an attractive appearance and resistance to the growth of microcracks.

Mother-of-pearl grows on the inner layer of shells. It is composed of aragonite crystals. Aragonite plates refract light rays, so mother-of-pearl seems to be iridescent and contains all the colors of the rainbow. Shells with the most beautiful varieties of mother-of-pearl are usually found in the Persian Gulf, the Red Sea and the Pacific Islands. Dark mother-of-pearl is obtained from the shell of the sea mollusk haliotis, and white mother-of-pearl is obtained from the Indian sea pearl. Products made of mother-of-pearl were worn by the pharaohs in ancient Egypt BC. In the East, it is used to encrust vases, screens, lacquer boxes, buttons, mirrors and other household items.

At home, it can be obtained from the scales of any fish. Making mother-of-pearl can be an interesting chemistry experiment that your kids will love. In the scales of fish is the substance guanine, from which pearlescent pigment is made. Previously, such a pigment was often used in the manufacture of cosmetics, for example, to create mother-of-pearl varnish. A few decades ago, mother-of-pearl powder was sold in every pharmacy because it was considered beneficial to health. Carp is best for getting pigment. Buy fish from the grocery store, scrape off the scales, and put them in a glass jar. Add water and start stirring the liquid with a mixer until a silver spit is visible on the scales. It should start to separate in tiny crystals and settle into a sediment at the bottom of the jar. Strain the mixture and dry the mother-of-pearl powder.

Consider at the same time how to make mother-of-pearl watercolor from the resulting powder. This paint is well suited for children's drawings and the effect of a magical atmosphere. Imagine how delighted your child will be by drawing twinkling fairies or a mysterious snowy forest.

To create a paint, you will need gum arabic (that is, acacia resin) on a water basis. This substance can be found in art supply stores. Prepare the same place where you will pour the finished paint. Containers from used cosmetics are well suited for this. A small square lip balm container works well. Very carefully pour the mother-of-pearl into the container. It is so light that it scatters around the room at the slightest breath of wind. Add resin at a ratio of about four parts mother-of-pearl to one part resin. After mixing, the consistency should not be liquid and contain lumps. Press on top with a spoon and the paint is ready. There is another option for obtaining mother-of-pearl paint in a purely chemical way without the help of powder. Find barium thiosulfate. Its crystals, mixed with clear nail polish, will give the polish a pearly color. If they are introduced into wood glue and applied to a hard surface, a mother-of-pearl effect will be obtained.

To imitate mother-of-pearl plates in the manufacture of souvenirs and the design of notebooks, you can use a bone glue solution sprinkled with magnesium sulfate. A mixture of fish scales with glue is applied to the layer of the resulting salt crystals and covered with a gelatin solution on top. Faux mother-of-pearl pairs beautifully with mahogany and ivory. Jewelry from it favorably sets off dark skin.

Lipstick, nail polish or eye shadow looks completely different when you add mother-of-pearl to them. It is often confused with pearls, which is not surprising, because both have a similar composition and origin. And yet mother-of-pearl is an independent stone. It has its own characteristics, magical properties and purpose.

Not all gems come from rock. There are decorative stones that were once part of the biological structure. Mother-of-pearl, like coral, amber or pearl, is one such organic mineral. But what is mother-of-pearl as a mineral?

Mother-of-pearl is an iridescent iridescent layer inside a pearl mollusk. The German name for the stone means "mother of pearls". And this is true, because any shell into which a grain of sand or other foreign fragment has fallen will create a pearl.

If nothing got inside, the mother-of-pearl layer does not envelop the grain, but grows on the walls of the mollusk.

Chemically, the mineral is calcium carbonate (CaCO3), which is based on carbonic lime or aragonite (85%) with an admixture of conchiolin (12%) and water (3%).

The strength of the material is low - 2.6–4.6 on the Mohs scale. Iridescent overflows are created by the unique arrangement of aragonite layers, which refract sunlight in different ways.

From the point of view of a gemologist, this is not a gem, but the decorative properties equalize mother-of-pearl with them.

Natural stones are fragile, so they are processed only by hand by qualified craftsmen.

History of the stone

Mother of pearl has been known to people for thousands of years. It is found in the tombs of the pharaohs of Ancient Egypt, a stone necklace made five millennia BC was dug up in Iraq.

In the East, walls of palaces, dishes, household items were decorated with this stone, and it was white material that was considered the favorite.

Ancient healers used the mineral as an antiseptic for wound healing, and the medieval ones expanded the scope by grinding the stone for healing tinctures and potions.

He brought more than one monk of Medieval Europe to sin. Pieces of mother-of-pearl, in a "package" with God's blessing, they sold as "feathers of angel wings" to wealthy parishioners. Having quickly become rich, they abandoned monasticism in favor of worldly life.

Russia got acquainted with mother-of-pearl at the end of the 17th - beginning of the 18th centuries. Churches and interiors were decorated with mineral, the nobility was proud of magnificent caskets, snuff boxes decorated with iridescent material.

The Roman emperors knew the properties of the stone to endow the owner with wisdom and the gift to read the thoughts of others, and Nero ordered that the walls of his palace be lined with iridescent plates.

The stone was valued by Mary Stuart and Catherine the Great, whose mother-of-pearl collection of hundreds of items is admired today by visitors to the Hermitage.

Deposits and mining of the mineral

Mother-of-pearl as a stone is not specifically sought, but mined along with pearls. And not from the earth's firmament, its deposits are water depths.

They are framed in gold, but mother-of-pearl is flawless with silver. This combination has been in fashion for more than a century and, presumably, will not lose popularity.

Mother-of-pearl jewelry organically complements both business and romantic outfits.

Stone processing includes grinding, cutting, polishing, shaping, engraving, one product is created by a whole team.

Mother of pearls - this is how the word "mother of pearl" can be translated from German. This beautiful natural material inspires not only jewelers to create wonderful jewelry, but also chemists who want to recreate the unique properties of the substance in the laboratory by all means. Slowly approaching their goal, they have already achieved significant results.

But still, a person has not yet managed to create anything similar in terms of the spread of the physical characteristics of the initial materials and the final product (in this case, it is mother of pearl). That is why the latest achievement of scientists looks so impressive compared to the rest.

In the course of research, chemists have found that the high strength of mother-of-pearl is determined by its structure. It was her authors of the work who tried to recreate.

To do this, they conducted a controlled freezing of an aqueous suspension of aluminum oxide (alumina) with the addition of a fairly common polymer, polymethyl methacrylate (PMMA).
The researchers reported their findings in the journal Science.

The roughness of hybrid ceramics also determines its strength, as it affects the shear process of the "bricks", and hence the energy dissipation. The inset shows fairly large briquettes of the new material. Previously, scientists were able to obtain samples of such a strong substance only in the form of thin films. In the same place - a photograph obtained using a scanning electron microscope, showing the behavior of the material under load. The damage spreads in the form of small cracks (photo by Lawrence Berkeley National Laboratory). Their discovery was based on work two years ago by fellow Berkeley researchers Eduardo Saiz and Anthony Tomsia.

Then scientists discovered that it was possible to create a very durable artificial replacement for human bone by freezing sea water.

This time, the chemists first also froze water, but in order to create a matrix that became the basis for obtaining a frame from alumina plates (lamellae) (it occupied pores not filled with ice). The ice was then removed by evaporation, and a polymer was introduced in its place.

The strength of a material is determined by its ability to dissipate strain energy. In this case, the polymer between the aluminum oxide plates allows them to "slide" relative to each other and thereby distribute the load, just like the protein structures in mollusk shells do.

But chemists were not only able to create a lamellar framework. They got the opportunity to influence the thickness of the plates, their macroscopic orientation, chemistry and roughness of the lamella interfaces. By compressing the framework perpendicular to the layers during sintering, they also obtained aluminum oxide "bricks" and achieved the formation and compaction of ceramic bridges between them. The possibility of varying all these parameters will allow in the future to obtain materials with other properties, and there is a high probability that among them there will be those that will be even better than the current ones.

“We tried to mimic natural hardening mechanisms by making alumina particles line up in hierarchical structures,” says Ritchie in a press release from the laboratory. “In the future, we hope that the study of already obtained composites will improve the synthesis of lightweight non-biological materials with unique hardness and strength.”

In the future, chemists intend to obtain materials with even greater strength. They hope to achieve exciting new results by changing the alumina/PMMA ratio to increase the ceramic content, replacing the polymer with a different one, and even replacing the entire polymer with a metal.

Scientists from Berkeley believe that the metal will not only allow the plates to move relative to each other (with such dimensions, this is quite feasible), but will also take on part of the load. In addition, unlike polymer, it can work at high temperatures.

The result will be a lightweight and durable composite material that will always find use in both the energy and transportation industries, the researchers believe. It suffices to give a simple example: many car parts made of such a composite will weigh much less than steel, which will positively affect fuel consumption.

However, before the idea becomes a reality (allowing manufacturers to benefit), it will be necessary not only to improve the material itself, but also to organize its mass production.

It has a characteristic iridescent tint. This is due to the structure of the shell itself, consisting of the smallest plates, separated by the thinnest air layers that refract light rays. Although this mass consists of thin layers covering each other, gradually released by the body of an animal living in a shell, it is very strong.
Mining
The main places of extraction of mother-of-pearl shells are the Persian Gulf, the Red Sea, Ceylon, Japan, Borneo and the Philippines, some tropical Pacific islands, the USA, Mexico, and Canada. Freshwater pearl oysters are practically extinct, sometimes they are found in the rivers of Northern Europe and in the Russian North. High-quality mother-of-pearl is mined only in tropical seas.
Most of the market is mother-of-pearl, mined by divers from shells in the process of searching for pearls. However, there are shells in which mother-of-pearl is much larger than in ordinary ones - they are mined separately. The color of mother-of-pearl varies depending on the place of production - for example, the Indian mollusk Manilla produces exclusively white, the mollusk abalone-haliotis produces dark red mother-of-pearl.
Story
Mother-of-pearl has been known to man for a very long time and was among the first known ornamental materials - necklaces, earrings, bracelets and other jewelry with this stone are found in the tombs of Ancient Egypt. In ancient Rome, mother-of-pearl was valued on a par with pearls, being considered a symbol of wisdom and power - according to legend, the walls of the palace of Emperor Nero were lined with mother-of-pearl plates. During the Middle Ages, goblets and vessels decorated with mother-of-pearl were especially popular among the nobility - for these purposes, whole elegantly twisted sea snail shells were also used, set in silver and decorated with fine engraving depicting mythical sea monsters or mermaids. It was believed that a drink poured into a similar cup heals from serious illnesses and prolongs life.

In Russia in the 18-19 centuries. in most jewelry, along with precious stones, mother-of-pearl was used, which was a favorite insert for court jewelers; bowls, snuffboxes, boxes, church utensils were also decorated with mother-of-pearl “scales”. Mother-of-pearl necklaces were worn by Mary Stuart and Catherine II.

Part of a jewelry set (15 items in total), diamonds, gold, mother-of-pearl, 18 c (from the collection of the Diamond Fund).

Until the 18th century, mother-of-pearl powder could be bought at any pharmacy - it was considered a unique healing agent (today mother-of-pearl is also actively used in cosmetology and pharmaceuticals).

Artificial mother of pearl
To date, the extraction of shellfish containing pearls and mother-of-pearl is very limited. The need for pearls and mother-of-pearl is much greater than nature can provide - the shells grow for a long time and are quite difficult to extract. The manufacture of artificial mother-of-pearl, which is produced using gelatin and "pearl essence", has long been established. This substance (essence d'Orient) is a liquid from the scales of bleak (Ukelei, Cyprinus alburnus). The scales are rubbed with water until all the shiny pigment settles to the bottom of the vessel. This precipitate is washed with ammonia and mixed with diluted gelatin. A substance with a silver sheen consists of microscopic crystals, a compound of guanine with lime. The method was invented in the 17th century in France.

Mother-of-pearl is used to make jewelry (rings, bracelets, earrings, beads and necklaces, pendants) and accessories (buttons, fans, caskets, mirrors, combs, etc.), encrust furniture, musical instruments, and household items.


coin box lipstick case cosmetic cigarette case

binoculars and fans

jewelry box and handbags

handbags and pill box

cufflinks, powder box and spoons (I'm touched)))

The main method of processing - mother-of-pearl is sawn with a special steel saw, then the top layer is removed with a sharpener, then it is turned and smoothed. At the last stage, it is polished with a special solution with sulfuric acid, which gives additional shine to mother-of-pearl.
Mother-of-pearl can be dyed, this process takes 2-3 days and the main color is black, as it is very popular and has unusual shades. The mother-of-pearl inlay technique is popular, wood, precious metals and stones are taken as the basis. One of the modern trends in jewelry is mother-of-pearl mosaic - the surface is inlaid with small pieces of mother-of-pearl, which eventually add up to an unusual picture with a large number of refractions.

Real mother-of-pearl is determined by heating, an open flame. Mother-of-pearl brought to it, containing 2% water, cracks and loses its luster. Mother-of-pearl is afraid of exposure to acids, abrasives, fumes, cosmetics.
Caring for mother-of-pearl jewelry is simple - they are washed in soapy water or rubbed with potato starch to remove dirt; The main rule is to keep mother-of-pearl clean. The “mother”, like the “child” pearl, suffers from a lack of attention and only gets better with frequent wear.

Sites used in preparation: etsy.com, dragkamen.ru, abc-jewels.ru, bizhuterija.com, bicostyle.ru, kamni-minerali.lact.ru, inmoment.ru