Pearl stone is unique among its counterparts. After all, it is the only one that is a product of animal origin, but at the same time belongs to the category of stones. The method of its formation looks quite simple: a speck of dust or a grain of sand falls into the shell of a mollusk, which gradually begins to become covered with layers of mother-of-pearl. Growth period natural pearls about 12 years old. This produces a gem that is unique in its properties and origin.
Pearls are often called nature's generous gift. Today it is classified as an organic mineral. At the same time, the amount of natural mineral is quite low, which naturally creates its high cost in the jewelry market. Based on the place of formation, pearls are divided into river and sea pearls. Due to the fact that it is not so often found in its natural form, it began to be reproduced in other ways, as a result of which today there are 3 groups:
- A natural stone
- Cultivated (grown by humans)
- Artificial
The special value of pearls is the play of light on its surface, as well as a certain characteristic shine.
Pearls: physical properties of the stone
The pearl stone, whose properties are highly valued in the world, gets its name from the place where it grows - from the shell. Essentially, this mineral is plates of aragonite, which consists of calcium carbonate. The stone is mined in warm seas.
The composition of the pearl includes more than 80% potassium carbonate, about 12% comchiolin and 2% water. The hardness of the stone is 31.5-4, and the density is 2.175-9%. It is worth considering that black pearls are less dense - they are equal to 2.61-2.69. The stone is completely opaque.
This stone can be varied in color, but in general remains within the pastel range. Thus, for a long time the white color of pearls was considered the most expensive. Today it is one of the most common. In addition, today there are stones with a varied tint - blue, yellowish and even pink. There are also black stones in nature (they are considered the rarest and most expensive today).
There is a separate classification according to the place of origin of pearls. For example, river stone is more uneven. Marine options, in contrast, have a more even ball shape. It is worth considering that since the product is organic, over time it can dry out, crack and even decompose. This should be taken into account when choosing the optimal conditions for storing the stone. For example, dry air, high humidity, excess sweat, cosmetics, various fats and the use of household chemicals will negatively affect the condition of the stone.
Mineral deposits
Naturally, many are interested in where exactly pearls grow. The fishing for such stone has been going on for centuries, and all the places rich in it have long been known. For example, pearls are mined in India, in the Gulf of California, and in the Bahamas. There are origins of pearls in Mexico, Tahiti, Sri Lanka, and off the coast of the Persian Gulf. The mineral is also mined in Australia, America, Germany and China.
Magical and healing properties of the stone
The pearl stone, whose magical properties have been known for centuries, is considered a feminine stone. After all, it helps ladies to reveal their properties most deeply and fully. If the question arises: who is the pearl stone suitable for, then we can safely say that it is better for men to refrain from using it, because... He makes them weak-willed, apathetic and lethargic.
Pearls are often called a symbol of purity and purity of soul, so they are often recommended as a gift for brides. This gem also helps strengthen friendship, reduces the likelihood of betrayal and minimizes the commission of unseemly acts by loved ones and acquaintances.
If jewelry with pearls is worn by an angry and envious person, they may darken, dry out and crack.
As for the healing properties of the stone, it has a fairly pronounced effect. For example, powder from this gem was traditionally used as a hemostatic agent. In addition, pearls are often endowed with disinfecting properties, because... According to research, it is able to stop the proliferation of bacteria and viruses.
Pearl water, which is used quite often, helps normalize digestion and significantly improves the quality of the skin. To obtain such healing properties, it is enough to infuse a couple of natural pearls in 0.5 liters of water at night.
Pearl stone: who is suitable for it, astrology
Naturally, astrology could not ignore such a strong stone. Therefore, the question is the compatibility of the pearl stone and the zodiac sign. For Cancers, such a mineral will bring calm and balance, and their blood pressure will also normalize.
For Taurus, such a stone is also useful in terms of combating depression; often pearls can make it easier for them to pass through bad streaks in life. For Libra, pearls will help relieve pride.
For Sagittarius, it is advised to choose black versions of pearls, which will balance psychological condition person. For Aquarius, pearls will be an excellent talisman that helps them get out of conflicts. The stone will help them create a good relationship with others. For Capricorns, the stone will be an opportunity to objectively assess the situation and find peace.
But Leos should avoid using such a stone, because... it will disrupt their peace of mind and comfort from a psychological point of view.
Our planet is simply replete with a variety of incredibly beautiful and luxurious precious stones. But it was pearls that received special attention. The properties of the stone and its origin aroused interest even in ancient times. People believed that pearls had powerful energy, healing powers and inexplicable power. However, more details about everything in our article.
A few words about the origin of the name
Where did the name “pearl” come from? The stone, the properties of which we will consider below, was first discovered by the Arabs. Therefore, the name comes precisely from the Arabic word “zenchug”. This determined Russian name"pearl". The properties of the stone made it possible even in those days to use it for healing and magical purposes. It used to be believed that if you drink a cocktail made from buffalo milk and crushed pearls, you can master the gift of clairvoyance.
Origin of the stone
The stone is formed in the shells of mussels and oysters. Most often, the parents of pearls are the shells of pinctada oysters, which live in the Pacific and Indian oceans. The size of the mollusk is only 130 mm. Today, the catch of pinctada oysters is limited due to the depletion of natural pearl populations.
The color of the stone is not only white, but also black, pink, green, red, yellow and blue. Average age varies from 120 to 150 years.
- The first mention of jewelry made from this stone dates back to the 2nd century AD. e.
- The most the most ancient decoration A necklace from Susa, found in 1901, is made of pearls.
- The bronze figurine of Aphrodite herself was decorated with gold earrings, inside of which there were small pearls.
- The oldest stone that has survived to this day belonged to the American actress Elizabeth Taylor.
- The largest pearl in the world is considered to be the “Pearl of Allah”. It was extracted from a giant oyster weighing 300 kg. Its size corresponds to the size of a coconut, and its weight is about 6.5 kg. The man who found the giant oyster died. She pinched his hand, making it impossible for the diver to get to the surface.
- Pearls are considered the stone of believers. IN Ancient Rus' they decorated icons, frescoes, crosses and many others. etc.
The magical properties of pearls
In China, it was believed that pearls were the main ingredient in the elixir of youth. The stone, whose properties are multifaceted, was also revered in Mongolia. They believed that pearls were a symbol of power. The Indians claimed that this beautiful stone patronizes family and love, and also gives well-being and prosperity.
The ancient Egyptians were sure that pearls were a symbol of longevity and beauty. The magical properties of the stone were also useful to Cleopatra herself. Few people know that the Egyptian queen was a fan of pearl jewelry. Cleopatra's maids regularly prepared her a drink consisting of crushed pearls (soaked in vinegar) and pomegranate juice. The queen considered this cocktail a real elixir of youth and beauty.
In the Bible, pearls were also considered a symbol of wisdom and restraint. The stone, whose properties are priceless in all respects, is mentioned in the famous phrase of Jesus Christ: “Do not give what is holy to dogs, and do not throw your pearls before swine, lest they trample them under their feet and turn and tear you to pieces.” (Bible, Matthew 7:6). With this statement, the Savior wanted to say that there is no need to argue and conflict with those who do not believe and are stubborn.
In medieval times, a symbol of good luck family life It was pearls that were considered. The magical properties of the stone made it possible to protect the bride from lustful thoughts and betrayals. It was believed that such a gift could not be re-given or passed on by inheritance, otherwise it could bring trouble to the former owner and the current owner of the stone.
This stone does not tolerate those who are weak in spirit and unsure of themselves. IN in this case he can “take advantage” of this and take over the thoughts and feelings of these people. Greedy, greedy, deceitful and proud people “don’t like” pearls. The stone will try its best to refract these qualities.
What else can you tell about pearls? The properties of the stone allow you to endow its owner with wisdom and chastity, helping to avoid conflict situations and find mutual language with people.
This is how proud and mysterious it is - a pearl. The meaning of the stone magical properties, we have already examined the origin of the name. It's time to talk about what medicinal properties has pearls.
Place in medicine
Few people know that pearls are included in many medicines. Japan, for example, still reveres this wonderful stone as a healing agent.
Even in ancient times, pearls were used to cleanse and thin the blood. Also, the powder from this stone made it possible to instantly stop bleeding.
Very good remedy pearls are also considered for cores. Many people claim that by holding the pearl in your mouth for a while, you can stop the arrhythmia.
Pearls were also famous in dentistry. In ancient times, its powder was used to clean and whiten teeth.
Pearls are also effective against poisoning, heat, asthma, epilepsy, eczema, various inflammations, bone tissue diseases, diseases Bladder, urinary tract and liver.
Pink pearls are reputed to be a good healer for allergies.
This will also help your eyes healing stone. It will relieve the visual organs from fatigue, remove excess moisture and protect against night blindness.
Today there is an opinion that pearls can prolong youth, which is why they are the main ingredient in many anti-aging skin products.
In ancient China, pearls were one of the main components in the preparation of the elixir of immortality.
Indians drink a drink infused with pearls in the morning to boost their immunity.
Pearl (stone): properties. How to wear?
It is not recommended to wear jewelry made from this stone to people whose work involves children, creative activities, or travelers.
Few people know that pearls are also called “widow’s stones,” so young girls and women should not wear them. married women. It can provoke the death of a husband or lover. For widows, on the contrary, pearls will help them find their soulmate.
Men who are womanizers do not need to wear this stone, because it is a symbol of love, devotion and fidelity.
Pearl (stone): properties. Who is it suitable for?
Pearls are considered an unlucky jewel, as they contain the negative power of the Moon. For many it brings tears, loss of hopes and illusions. But there are also those for whom the stone favors and brings only good luck.
The only zodiac sign that pearls suit is Pisces. It promotes prosperity and longevity, brings happiness, protects from unrequited love, protects against the evil eye, gives its owner the ability to foresee, protects against unsuccessful transactions and thieves. Pearls “love” their owner immensely. It is believed that with his death, the pearls fade and die with him.
“Tears of melancholy” is the name given to jewelry containing pearls. The stone's properties for Virgo, Taurus, Capricorn are more likely to be destructive than positive. After all, these signs belong to the element of Earth, and, as the stars say, pearls are contraindicated in this case.
A few words about black pearls
Black pearls, a stone whose properties are not known to everyone, were revered in ancient times and were a symbol of belonging to high society.
The Chinese believed that black pearls imparted wisdom and chastity, protected against the “evil eye,” helped scare away thieves and warned against rash actions.
There is a belief that a person who owns this beautiful stone interacts with it energetically. Black pearls, a stone whose magical properties are incomparable, protect its owner from harm, and he, in turn, cherishes and preserves his beauty. As soon as the stone goes to another owner, it immediately loses its strength and power.
They say that black pearls can lose their love and trust in their owner. And as soon as the owner crosses the line that contradicts life’s morality, the stone can crumble.
What else can black pearls tell about themselves? The properties of the stone allow you to prolong life, treat various diseases, protect from enemies and bring good luck in all endeavors.
For women, this stone will bring wisdom, sexuality, sensitivity and happiness. As for men, the situation is the opposite. In this case, black pearls will only bring disappointment, misfortune and failure.
In ancient times, black pearls were a symbol of health and healing power. The stone, whose properties are not only positive, had the ability to increase the tone of the body, rejuvenate it and increase resistance to diseases.
It is believed that black pearls, like no other, can treat ailments of the skeletal system, fractures and epilepsy.
Conclusion
I would like to believe that this beautiful stone will not bring grief to anyone, because its brilliant appearance denies all negative consequences.
Pearls got their name, which means “sea shell”. The stone does not have a transparent surface and is not illuminated. Its peculiarity is the mysterious mother-of-pearl and dazzling shimmers that play with all their reflections, both in the rays of the sun and in the moonlight.
It takes more than one year for a grain of sand that falls into a mollusk shell to form a pearl. And for larger stones it takes ten years. The formation process is interesting because when it enters the body of a sea creature, a protective reaction is triggered and thereby wraps the grain in nacre. This is how a gem of unusual beauty is formed.
People who wore pearl jewelry belonged to the category of noble and rich who had their own big houses, furnished according to latest trends. Many society ladies attended events wearing such beads and earrings, arousing the admiration of men.
Pearl colors and varieties
There are more than 100 different shades of this stone. It is extremely rare to find pure pearls white, often it has a silvery sheen. Just like white, it is almost impossible to find a bluish-green gem. The most expensive pearl is black. Such demand and cost is due to the fact that white colors are more common than colorful and stylish dark ones.The structure of pearls. A pearl consists of a core, a main part and a shell. The core makes up at least a fifth of the pearl. Sometimes it is absent, then its location is guessed by the whitening in the center of the pearl caused by the appearance of pelitomorphic aragonite. There is rarely a void in place of the core. The core does not affect the quality of the pearl; its role is purely genetic: the growth of the pearl begins from it. Foreign bodies can be detected in the nucleus. These are minerals that accidentally fell into the sink, and clumps of organic matter deposited as a result pathological changes in the body of a mollusk.
Minerals are represented by grains of plagioclase, quartz, particles of kaolinite and mica plates. Accumulations of organic matter are round or irregular in shape. Sometimes such a cluster occupies about half of the cross section of the pearl. It is lighter in the center, dirty brown at the edges, and soft. Round clusters usually do not contain any impurities; irregular ones often contain flake-like particles of aragonite.
The core of the pearl is often surrounded by a thin layer of organic matter, which stands out well with its dark color against the gray background of aragonite crystals. The bulk of the pearl grows directly on it. It consists of prismatic (columnar) aragonite crystals, which are separated by thin organic layers. The organic matter gives a brownish tint to the entire pearl.
Prismatic aragonite crystals have four-, five-, six-, seven- and octagonal cross-sections. The study of the cross section allowed us to identify three types of crystals and intergrowths. Crystals of the first type are few in number; their cross-section is quadrangular and hexagonal. The planes of prisms (010) (the first type of crystals), (010) and pinacoid (100) (the second type) take part in cutting. Crystals of the second type predominate. The main (habitus) on all crystals is the prism (BUT), the pinacoid (100) always has a subordinate value. Apparently, crystals of the first type formed earlier than others. Compared to subsequent aragonite deposits, their edges are the smoothest. Crystals of the second type have an irregular cross-section, their edges are usually slightly concave or curved. These are essentially curved crystalline formations. The crystalline formations of aragonite of the third type are even more curved. For this reason, determining the edges in them is very difficult. Each aragonite crystal grows on a conchiolin (organic) base and in a conchiolin sheath.
Examination of sections of prismatic crystals in their root part suggests the existence of two varieties of conchiolin: one to some extent predetermines the shape of the future aragonite crystal, the other, surrounding the crystal with a kind of cover, ensures its growth. It also protects the crystals from sticking together.
In aragonite of freshwater pearls, in areas where there is a lot of conchiolin, another type of crystal can sometimes be traced. By analogy with the formations known in mineralogy, this aragonite should be called skeletal. In cross sections, it is revealed due to narrow, two- and three-edged stripes that repeat the outlines of the aragonite crystal located nearby. The framework of skeletal formations is usually torn.
Prismatic crystals determine the radiant-shell structure of the pearl. It is the result of seasonal deposition of calcium carbonate by a mollusk that is sensitive to the slightest changes in the external environment. The described layering is close to the layering of “cave” pearls, in which the age can be determined by the number of layers and their width. However, this is hardly acceptable in relation to pearls; the mollusk in which pearls are formed reacts not only to seasonal, but also to other changes in the environment.
Prismatic aragonite crystals grow on a thin layer of organic matter and, as it were, serve as a natural continuation of the previous prismatic layer. Toward the periphery of the pearl, the amount of organic matter in it usually decreases. Such pearls are slightly translucent. In pearls where the organic layers are very thin, the prismatic crystal of aragonite can be traced along its entire length. When the layers of organic matter are noticeably thick, the aragonite prisms are clearly separated from one another, and their orientation becomes different.
The color intensity of many pearls depends on the amount of organic matter covering the ends of the prismatic crystals. Its significant areal distribution determines Brown color pearls There is no shell as such in such pearls. The tops of aragonite crystals are clearly visible on the surface, many of them are rounded. This suggests the presence of small faces at the tops of the crystals, which, unfortunately, have not been studied at all. The nature of the irregular white spots visible in the depths of brown pearls has not been studied either.
Lamellar layers of aragonite grow on the prismatic layers, causing the pearlescent luster of pearls. Sometimes they form not only the shell, but also the whole pearl. Such pearls are slightly translucent. The plates (they can be called crystals) more often have a hexagonal appearance, less often they are quadrangular and pentagonal, irregular. Their size is from 3 to 30 microns in diameter, thickness up to 2.2 microns. The thickness of the mother-of-pearl shell is 0.5 mm. As in the nacre layer of a shell, the aragonite plates in pearls are oriented with their main axis perpendicular to the growth surface, i.e., the picanoid (001) face of the plates is parallel to the plane of the layers.
Like the crystals of the prismatic layer, lamellar aragonite crystals are enclosed in conchiolin capsules. Through them and thin layers of organic matter, the plates are separated from each other. The same substance holds aragonite plates together into a compact mineral-organic aggregate.
Lamellar layers often occupy only part of the surface of the pearl, while prismatic layers are exposed in other areas. To this it should be added that sometimes we are talking not so much about layers, but about sagging and even films of mother-of-pearl, which can be easily cleaned from the surface of the pearl with a steel needle.
A study of the structure of lamellar layers of white (jewelry) and gray pearls conducted by geologist A. A. Korago showed that the first is characterized by high degree homogeneity. It manifests itself in the uniform size and thickness of the aragonite plates secreted by the mollusk and the films of organic matter that glue them together. The shell of gray pearls is composed of aragonite plates, the size and thickness of which vary widely. The thickness of the layers of organic matter is extremely variable. Both pearls also differ significantly in surface (simple in the jewelry pearl and complex in the gray pearl), the nature of which depends on the location of the lamellar crystals in the shells.
River pearls are composed mainly of layers of prismatic aragonite crystals. The lamellar (pearl) layer on them has a small thickness. Apparently, this is why such pearls shimmer with pale moonlight.
Sea and freshwater pearls differ somewhat in structure. Precious sea pearls are composed of layers of plate-like aragonite crystals; they do not have prismatic crystals. However, the structure of pearls made from mussel shells does not follow this rule. Pearls caught in Feodosia Bay consist mainly not of lamellar layers, but of prismatic aragonite crystals, gray in the center and white on the periphery. The layers are separated by thin pads of organic matter. The width of the concentrations is hundredths - thousandths of a millimeter.
A detailed study of Black Sea pearls was carried out by E. F. Shnyukov and D. P. Demenko. Using electron microscopy studies, they identified crystals of calcite and hydromica in the core of pearls and for the first time recorded a layer of loose collomorphic aragonite in the structure of pearls. This layer is penetrated by numerous pores directed from the periphery to the center. The pores branch and, according to researchers, are important channels in the pearl. In individual pearls, not one, but two collomorphic layers are developed, which are well separated from each other. However, in this case there are no pores in both layers.
The surface of the colloform layer is covered with lamellar aragonite crystals. Where there is no colloform layer, the pearl is entirely composed of aragonite plates with a cross-section of 3-4 microns. The surface of the plates is dotted with numerous tubercles, spherical formations and occasionally penetrated by pores. The chipping of the plates is conchoidal. Shnyukov and Demenko discovered elongated prismatic fibers with a length of 0.2-2.0 and a thickness of 0.04-0.1 microns on a transverse chip after etching with a weak alkali solution NaOH. The fibers are oriented mainly perpendicular to the surface of the plates. Transverse growth streaks are noticeable on the prismatic edges of the fibers.
The quality of pearls is determined by four characteristics: luster, color, shape and size. The main sign is shine, and then color.
Shine. Pearls must have a play of color, light (sparkle) and shine, without which they are of no value. The beauty of pearls is not only in color, but also in the shimmer, which depends on the degree of transparency of the aragonite layers and the reflection of light from them. This phenomenon, called orientation, is a consequence of two optical effects: the interference of light reflected from successively overlapping transparent plates of aragonite, and the diffraction of light as it passes through the crystal lattice of aragonite layers at the points where the latter meet the uneven surface of the pearl. The first effect is more constant and varies from a subtle flicker to flashes similar to the northern lights. Jewelers compare this effect to the “fire” of a diamond and, when describing the brilliance of a pearl, as when describing a diamond, they talk about the “water” of pearls. Pearls with a strong play of color are called fire pearls; they are extremely rare and very highly valued.
Pearls of “pure (or first) water” are required, first of all, to play: they must be colorless or pure white, have a strong shine with a “weak blue tint, turning into iridescent.” An impeccable pearl of “pure water” has a delicate milky-white, light-silver luster that shimmers with all the colors of the rainbow when it rotates. These are the most expensive pearls. White pearls with a yellowish or bluish tint do not shine through to the full depth of the nacre layer. Therefore, their shine is not as strong as colorless pearls - very soft, slightly velvety. This is the main charm of most commercial pearls. The greatest shine with a beautiful mother-of-pearl tint is characteristic of pearls caught in the waters of the Persian and Manara Gulfs.
Pearls that lack an orientation are unattractive. They are formed in the shells of mollusks lacking the mother-of-pearl layer. A classic example of such a pearl is the famous “Pearl of Allah” weighing 6.35 kg, extracted from a huge tridacna. The famous pinna pearl weighs 16 grains (1 grain = 50 mg) has a dull, dark brown color. The inner surface of the sink in which it was placed also has the same color. Many other pearls are also devoid of orientation. They are, as a rule, of no value, although from time to time there is a demand for them. There is no orientation in black pearls, but they attract with an extraordinary glare - a light speck of reflected light. These pearls are very valuable. Their shine is close to metallic. As already noted, pearls with a beautiful shine are formed in shells with a developed nacre layer. However, this rule is not always followed: the intensity of a pearl’s shine often depends on which part of the mollusk the embryo of the future pearl falls into. If the embryo is located in that place of the mantle where a beautiful pearlescent layer stands out, then High Quality nacre is also formed on the pearl. This is how pearls of “beautiful water” are formed, according to the terminology of the English jeweler G. Smith. In the middle of the muscular edge of the mantle, the pearls are brownish, without shine, often with whitish streaks that spoil their appearance. Pearls formed in the outer (dark) edge of the mollusk's mantle have no shine. The farther the pearls are from this edge, the lighter they are and the higher their jewelry quality. Directly above the locking part, both brown pearls, which have almost no shine, and white, shiny ones, are formed.
Color. It is believed that the best pearls do not have their own color. Thanks to their transparency, they acquire a soft silvery sheen, barely shimmering with the colors of the rainbow, and become pearls of the purest water. However, pearls can be white, pink, blue, bluish, violet, golden, yellow, bronze, gray, brown, reddish, brown, black, rarely greenish, but more often yellowish or grayish with a bluish tint and a characteristic pearlescent sheen. All colors except black are weak. The color of pearls is determined by the degree of translucency of the nacre shell and the color of the underlying organic layer. Pearl aragonite is colorless or white, while conchiolin is yellowish and, in relatively thick layers, brown to black. Impurities of chemical elements in the water where pearl-bearing mollusks live significantly affect the color of pearls.) Therefore, pearls from different bodies of water sometimes differ noticeably in color. Caught in the waters of the Persian Gulf they have a creamy color. Pale pink color is characteristic of pearls from Sri Lanka. Australian pearls are white and silver-white, Mexican pearls are reddish-brown and black, Indian pearls are bright pink with wavy lines, and Japanese pearls have a greenish tint. An unusually beautiful golden color is characteristic of Australian pearls extracted from mollusks. In some cases, the color of a pearl also depends on its position in the body of the mollusk.
Black pearls are unique. It has been known for a long time as a precious decoration. In Homer's Odyssey, Penelope receives a pair of pearls, "as if woven from mulberries." Absolutely round black (without smudges) pearls are very rare. Compared to light-colored pearls, they contain more conchiolin. For a long time, the Bahia region in the eastern part of the Gulf of California enjoyed worldwide fame. Black pearls with a characteristic metallic sheen were caught here. The pearls had a special name “La Paz”, or “Panama”. The most expensive ones weighed 372 grains.
Freshwater pearls are no less varied in color. Thus, in the reservoirs of the North-West of the USSR they find white, gray, greenish, brown, black and combined. White pearls are rich in shades: pinkish, golden, bluish, silvery, grayish, lilac. Such pearls have a mother-of-pearl luster and sparkle and are of jewelry quality. White pearls make up about a quarter of all pearls found, gray pearls about a third. Gray pearls do not have shine or sparkle and do not shine through. In addition, they often have a greenish, beige or brownish tint. Greenish pearls are few in number and, as a rule, small (3-4 mm). Black pearls are very rare. Like gray, it is not translucent, lacks shine and sparkle, and this differs significantly from the famous black pearls of the southern seas. However, previously black pearls with a characteristic bluish tint were found in the rivers of the Kola Peninsula. Norwegian queens wore necklaces made from such “Hyperborean” pearls.
A large group consists of pearls of combined colors: white with gray stripes, brown with a gray belt, or gray with a white (and brown) “crown.” Many pearls consist of two halves, one of which is characterized by jewelry properties, and the other, gray or brown, does not.
Karelian pearls are mostly silver-white, sometimes with a bluish tint, pink, less often black with a steel-blue tint. In the rivers of the Arkhangelsk region, along with silver-white pearls, red-white, red with blue and gray pearls the size of a pea were caught.
The color of a pearl is affected by its degree of maturity. M.V. Lomonosov wrote about this after examining pearls collected by S.P. Krasheninnikov in Kamchatka. Immature pearls are greenish, brown, yellowish, blue. One side of the pearl is white, the other blue or yellow. Often, when removed from the shell, pearls have a greenish tint and only turn white as they dry.
The nature of the color of pearls (and shells) is not well understood. It was noted above that the color of pearls depends mainly on the color of the organic matter found in it and on the admixture of various chemical elements in sea water. Very expensive, pink pearls grow in seawater containing elevated amounts of manganese. By enriching sea water on pearl plantations with various chemical elements, blue, green, orange and even purple pearls are obtained. The reason for the color of black pearls is unclear. Apparently, it is related to the characteristics of the water in the Gulf of California and other areas.
The color is affected by the porosity and specific surface area of the pearls, the structure of the seabed, the speed of underwater currents, water temperature, the genus of the pearl mussel and the color of its shell, and the place where the pearl is located in the body of the mollusk. But the main color factors are the type of mollusk and the admixture of chemical elements in the water. It is from their interaction that the rich colors of pearls are born. Cultured white pearls have no less than 26 shades - from dazzling white to pink and greenish. Japanese and French specialists have achieved significant success in growing multi-colored pearls.
It is believed that the color of pearls should be close to the skin color of the one who wears them, so people different countries They wear pearls of various colors. In Europe, preference is given to snow-white or white with a slight bluish tint, in the East and southern countries - yellowish or brownish pearls.
Form. Pearl, as already mentioned, is a kind of mineral-organic aggregate. Its emergence and growth are subject not to the laws of interaction of atoms, but to the biochemical laws of development of a living cell in the body of a mollusk. Therefore, pearls can have a wide variety of shapes. Even medieval authors identified up to 12 varieties of it. The shape of the pearl depends mainly on where the foreign body, the embryo of the future pearl, gets under the shell flaps. Pearls are round, oval (ovoid), oblong (cylindrical), pear-shaped, drop-shaped, hemispherical (button), irregular (baroque).
The most perfect, round pearls are formed in those parts of the mollusk where the mantle is sufficiently thick. In river pearl mussels best quality pearls are born in the mantle near the castle; they are almost colorless and small in size. They are usually referred to as the “dew drop” type. If a pearl appears near the shell wall or adjoins (grows) to it, then a so-called shell pearl is formed. It comes in two types: “bubbly” or “bud”, sometimes containing a foreign substance - water or silt, and solid - blister-pearls. When a grain of sand is introduced into the adductor muscle, the resulting pearl acquires a pear-shaped and teardrop shape or has a rather bizarre outline. Near the hinge edge of the shell, often above the hinge, narrow pearls with pointed ends are formed, often fused together.
The dependence of the shape, color and luster of a pearl on its position in the shell has not yet been sufficiently studied. Until now, science cannot satisfactorily answer the question: why do pearls of different qualities form in the same mollusk tissues? Meanwhile, such knowledge is extremely necessary when carrying out work related to the cultivation of pearls.
In Rus', separating pearls by shape became a practice back in the 16th century. Regular spherical pearls with a thick mother-of-pearl layer of white and silver color, which “rolls on a silver platter and does not stand still,” were called “sloping” or “rounded.” The further the pearl rolls and spins, the more ideal its shape and the higher its value. In ancient Russian epics and fairy tales, such pearls are mentioned very often. Ilya Muromets, in order to appease the evil Tsar Kalin, brings him “the first bowl of pure silver and the other of red gold, the third of stingray pearls.” Residents of the Russian North called round freshwater pearls “skaten”. Clothes were embroidered with ray pearls. It was given to the rulers of foreign states.
Round pearls the size of a pea or dragee were called “cargopolochki”, and those weighing less than 0.25 grains were called “family”. Their surface is smooth, shiny or slightly rough. Round unrounded pearls in Rus' were called saffron milk cap.
Oval pearls are rounded at the ends. Its surface is uneven, rough, with protrusions of different sizes. Large (over 6 mm) oval pearls in Rus' were called pearl cucumbers. They were valued quite highly.
Oblong pearls sometimes look like a small cylinder, which is why they are called cylindrical. Pear-shaped and teardrop-shaped pearls are rare in rivers of the European North. More often you come across hemispherical (button) pearls with a rounded top and a flat base, reminiscent of miniature loaves of bread; they are also called dies. Hemispherical pearls are smooth, shiny, sometimes with dark and light specks.
Irregular pearls have the most varied, sometimes very bizarre shapes. In Rus' such pearls were nicknamed “ugly”, “coal-shaped”, “horned”. From the 16th century it has a special name - “Baroque”.
Along with the best examples of river pearls, sea pearls were also famous, especially round, pear-shaped and teardrop-shaped pearls. Thus, the famous “Pilgrim” pearl is perfectly round. The famous “Peregrine” pearl has a regular pear-shaped shape, and the “Pearl of Hope” has a drop-shaped shape. These shapes are exceptionally good in pendants and earrings and are therefore highly valued. Remarkable examples of pear-shaped and round pearls are in the Diamond Fund of the USSR.
A fairly large group consists of sea pearls, shaped like the silhouettes of various animals or objects: the back of a frog, the head of a horse, the wings of a bird, a dog’s tooth, or even the body of a person and even his facial features. Such pearls are called paragons; miraculous properties have long been attributed to them. Paragons are set in gold and decorated precious stones. Beautiful paragons are kept in the State Hermitage.
In addition to individual pearls, intergrowths of pearls are occasionally found. A classic example of this phenomenon is the “Southern Cross” - nine round, cross-shaped pearls 4 cm long. It was discovered in an oyster caught in 1874 off the east coast of Australia. River hemispherical pearls grow together with their flat bases. At the site of fusion, a belt of pearls of later formation is often found.
Size. Pearls have different sizes. Tiny pearls, tenths of a millimeter in size, are called pearl dust. They have very limited use. Large pearls are rarely found. According to size - the weight of one grain - pearls are divided into three groups: no more than 50 mg; from 51 to 200 mg; from 201 mg or more. Pearls of the second group are more common, and among them - with a diameter of 0.3-0.6 cm.
The division of pearls into “large”, “medium” and “small” was known in Russia back in the 17th century. In official documents and literature they wrote mainly about great pearls. Thus, in the “Mineralogical Dictionary,” published in 1790, large pearls, which “are as big as cherries,” were called “cherry.” The “Olonets Statistical Collection” for 1902 reported that in 1871, 11 unusually large blue and pink pearls were sent from the Olonets province to the royal court. The wife of the Ural breeder T.N. Demidov wore a four-row necklace of pearls the size of a hazelnut.
At one time, the best pearls in color, shape and size were mined near the city of Kem on the White Sea. Even the city's coat of arms depicted a wreath of pearls against a background of blue water.
Like famous gems, pearls of rare beauty are called by their own names. As a rule, they are kept in state treasuries. The history of some of them, dating back hundreds of years, is full of amazing adventures and dramatic events. The history of the “Pearl of Allah” - the largest in the world - is interesting. It was caught in 1934 in the South China Sea off the island of Palawan (Philippines). Pearl weight 6.35 kg, length 24 cm, diameter almost 14 cm. In its own way appearance it resembled the head of a Mohammedan in a turban and therefore was called the “Pearl of Allah.”
They say that the son of a Filipino leader loved to get corals and mollusks with beautiful shells from the bottom of the sea. But one day the boy disappeared under water and did not rise to the surface for a long time. Divers who descended to the bottom of the sea found him dead. The young man's left hand was tightly grasped by the wings of a huge tridacna. The corpse of the young man and the tridacna holding him were taken to the shore. Using a crowbar, the tridacna was opened. Imagine the surprise of those present when they saw in the middle of the mollusk a giant, wrinkled, lobed, dimly shining pearl. The deceased's fellow tribesmen attributed magical powers to this pearl. Over time, it was presented to the doctor who saved the life of the second son of the Philippine leader, then New York jewelers became its owners. However, the “Pearl of Allah” is of no value, since it is devoid of mother-of-pearl luster.
In the 16th century The pearls from the dowry of the French queen Catherine de Medici were considered the best in Europe. After her marriage, she gave them to the Scottish Queen, Mary Stuart. Subsequently, the pearls became the property of the English Queen Elizabeth I.
In 1579, the Spanish King Philip II became the owner of the wonderful white pearl “Perigrine”, brought from the island of Margarita in the Caribbean. The island was named so because of the abundance of pearl shells on it (“Margarita” means pearl in Latin). The pearl has a perfect pear-shaped shape and a very beautiful mother-of-pearl shine. It is the size of a pigeon egg (length 3 cm, width about 2 cm, weight 252 grains). For “Peregrine” the king paid 100 thousand francs. The writer S. Zweig says that “Peregrine” was found off the coast of Panama by a black slave, who received freedom for it from the Spanish conquistador Nunez Bilbao. Having ended up in the treasury of the Spanish king Philip II, “Perigrine” was then given as a gift to the English queen Mary Tudor. After the death of the queen, the pearl returned to Spain, from where it was taken out by King Joseph Bonaparte in 1813. At one time, Perigrine was owned by the King of Holland, Louis Bonaparte. Later the pearl was sold to the English Lord Hamilton, in whose family it was kept for a long time. Currently, Perigrina is located in Spain.
In 1886, the mentioned “Southern Cross” was demonstrated at the Indian Exhibition in London. In 1889, at an exhibition in Paris, this unique pearl ensemble was awarded a gold medal. One of the rare black pearls was found in 1904 off the coast of Mexico by the Indian Buenaventura Hilles. The pearl was named “Requia Aztec” - “Queen of the Aztecs”. The following story is told about her and the fate of the Indian who found her. Buenaventura sold the pearl and immediately became rich. With the money he acquired, he could live peacefully for the rest of his life. But the Indian dreamed of finding a mate for the “Queen”; he even came up with the name “El Rey Montezuma” - “King Montezuma” (named after the Aztec king). For days the Indian searched for a beautiful pearl, which, alas, existed only in his imagination. He worked alone, without a partner. Great physical stress did not pass without a trace: one day Buenaventura plunged into the water and did not surface. After several days, the waves washed his empty boat ashore.
In 1917, a pearl the size of a sparrow egg, weighing 200 grains, was found off the coast of Australia. It was valued at 14 thousand pounds. Art. and was called the "Star of the West".
Large pearls are in the vaults of various states. In England there is a teardrop-shaped pearl weighing 2454 grains called the “Pearl of Hope”. Two pearls weighing 1800 and 320 grains are on display in the Geological and British National Museums in London.
In 1781, the treasury of the French crown contained more than a million francs worth of pearls; among them was one in the shape of a pear weighing 228 grains valued at 300 thousand francs. The royal house also owned the Regent pearl, of “excellent water and game” and the size of a pigeon’s egg, weighing 345 grains. Four hundred pearls of the highest grade, weighing at least 320 grains each, were in the possession of the French Empress Eugenie, wife of Napoleon III.
Judging by the description made in 1818, the “Pilgrimka” or “Wanderer” pearl from the treasury of the Russian state, found off the coast of India, had unheard-of beauty. Its weight is 112 grains, its color is white, and its shape is perfectly spherical. The pearl was completely round.
There are several other large pearls known in the world: “Khone”, “Shah-Safi”, “Queen of Pearls”. Their weight in grains is 1888, 513, 113, respectively.
Pearls have long been highly valued. In ancient Russian poetry, the very word “pearl” meant “precious”, “beyond all praise.” The best at all times was considered to be sloping pearls, with a thick nacreous layer, completely spherical, white or silver-white in color, with light iridescent tints. It is followed in value by black, mauve, cream and gold. Less valuable are blue, greenish, brown, brown, orange and yellow pearls. Thus, in the Novgorod Trade Book, when buying pearls in other countries, the following recommendations were contained: “Buy pearls that are all white, pure, but don’t buy yellow ones, no one will buy them in Russia.” Gray pearls generally have no price, although from time to time there is a demand for them. The most valuable pearls are oriental, which can be white or pink.
The price of a pearl is greatly influenced by its shape: the most expensive are regular spherical pearls, then pear-shaped and oval. The larger the pearl and the more perfect its shape, the higher its price. Under Peter I, a large pearl cost 100 rubles. per spool (4.26 g). The sale of two or three pea-sized pearls could support a family of pearlheads for a year. Two large pear-shaped pearls of the Egyptian queen Cleopatra were valued at 5.5 million rubles. A large pearl in New York still costs about 500 thousand dollars. Large pearls are sold individually, the weight is determined in grains or carats (1 carat = 4 grains). Small pearls are sold by weight, taking into account the quality of the pearls and how much is per ounce (about 30 g).
The high cost of natural pearls is explained not only by their rarity, but also by the danger and difficulty associated with extracting this gem from the depths of the sea. The price of cultured pearls was initially 0.2 times the cost of natural saltwater pearls, and later dropped to 0.1. Currently, all cultured pearls are sold for 90 rubles. for 1 year
Pearls are graded according to three classes. The first class includes perfectly round white pearls with a strong shine and a faint pinkish or bluish tint. Immaculate teardrop-shaped pearls have the same price as round ones. The second class includes not quite large pear-shaped or flattened pearls, white with a strong shine, as well as completely round white pearls with a weak shine. The third class includes all pearls with a low shine, which can at least partially be used for making jewelry.
The price of pearls increases in proportion to the square of its mass. Therefore, a pearl weighing 2 grains, all other things being equal, costs 4 times more than a pearl weighing 1 grain.
Few pearls can withstand the meticulous test of class. But if they endure and are rated with the highest score, then their cost becomes fabulous. It is not surprising, therefore, that large and beautiful pearls, along with diamonds, emeralds and rubies, are included in the register of currency values of the state; they are subject to a currency monopoly regime.
Hardness. Pearl Quite hard and durable, but scratches easily. The hardness of river jewelry and sea pearls was studied. The data obtained were compared with the hardness of ordinary aragonite.
The jewelry pearl is slightly oval. At its largest cross-section it is 2.9 mm. It consists of two zones: a wider inner one, composed of prismatic radial-fibrous aggregates of aragonite crystals, and a narrow outer one (0.5 mm), formed by lamellar layers of this mineral. The core in the pearl is not expressed. Prismatic aragonite is brown, lamellar - light gray, white. The surface of the pearl is pale pink with a good pearlescent luster. Translucent to depth.
The sea pearl is elliptical, with a slightly uneven, wavy surface. Its dimensions are 4X3.5 mm. It is characterized by an unclearly expressed radial-fibrous and concentrically layered structure. Composed of prismatic aragonite crystals. Width - hundredths to thousandths of a millimeter.
Aragonite is represented by short- and long-prismatic (from 2 to 18 mm) crystals and their twins (tees) with habit faces of a prism (110) and pinacoid (001) and a slightly developed prism (010). The edges of most individuals and joints are smooth and shiny, making it possible to determine hardness without preliminary grinding and polishing
The hardness of pearl aragonite and “terrestrial” aragonite was determined by geologist V.B. Stepanov under a load of 20 g, the load was maintained for 10 s. In a river pearl, the hardness of the internal (prismatic) zones and the outer shell, consisting of thin aragonite plates, was measured; in a sea pearl, the hardness was measured on the entire cross section of the sample. Aragonite hardness was measured on the faces of the prism (110) (along the axis With) and pinacoid (001). Each pearl and aragonite crystal face had 50 diamond pyramid impressions.
The spread of hardness values and the average hardness of pearls is greatest in the inner (prismatic) zone of a river pearl. The average hardness of aragonite prisms (206.56 kg/mm2) is almost 2 times greater than that of the nacreous layer plates (115.36 kg/mm2). The pinacoid facet of Shorsu aragonite is 2 times harder (266.5 kg/mm2) than the same facet of freshwater pearl aragonite (115.36 kg/mm2), while the hardness of the prismatic faces of both substances is almost the same (203.4 and 206.56 kg/mm 2). Sea pearl aragonite (170.06 kg/mm 2) is characterized by the lowest hardness (on the verge of a prism). The latter circumstance, apparently, can explain the shorter durability of sea pearls compared to river pearls.
The mechanical properties of pearls (like mother-of-pearl) are determined by the spatial arrangement of prismatic and lamellar aragonite crystals, connected into a compact mineral-organic aggregate through organic matter. In a direction parallel to the arrangement of aragonite crystals, such properties (including hardness) will be different than in a direction perpendicular to this direction. The elastic properties of freshwater pearls are higher than those of sea pearls.
Density. Pearls are aggregates of variable composition, so their density varies greatly. It consists of the density of aragonite (2.94 g/cm3), conchiolin (1.34 g/cm3) and water (1 g/cm3). Depending on the predominance of one or another component, the density of the pearl increases or decreases.
The results of studies of pearl density by various authors are given in table. 1.
Freshwater and sea pearls characterized by similar density values. The upper limit of freshwater and sea pearls is the same and equal to 2.78 g/cm 3 , the lower limit is different: for freshwater pearls 1.35 g/cm 3 , for sea pearls 2.43 g/cm 3 . Thus, the spread of density values for freshwater pearls is wider. The lowest density was observed in the black freshwater pearl (1.35-1.37 g/cm3). It is almost the same as conchiolin (1.34 g/cm3). Apparently, these pearls, according to Corago, consist mainly of organic matter. The highest density was determined for white silver-white jewelry pearls. It is somewhat unexpected that the density of yellow pearls increases to such an extent or limit, just like whites. Black sea pearls have a higher density (2.75 g/cm3) compared to the density of black freshwater pearls (1.35-1.37 g/cm3).
The density of cultured pearls is significant (2.70-2.80 g/cm3). It should be noted that the upper limit of the density of black cultured pearls (2.80 g/cm3) is higher than the same limit of sea and freshwater pearls. Obviously, this difference is due to the different composition of conchiolin. It is possible that the density of pearls also depends on the composition of impurity elements in it, but this issue has not been studied.
Component composition of pearls. In terms of component composition, pearls are similar to the inner layer of the shell - mother of pearl. It consists mainly of aragonite (10-95%), organic matter (4.5-85%), water (0.5-4%). On average, pearls contain approximately 86% calcium carbonate, 12% organic matter and 2% water.
The component composition of four pearls is given in table. 2.
The composition of aragonite, from which white pearls are almost entirely composed, has not yet been studied. As the aragonite in the pearl decreases, its color becomes more intense. Brown pearls contain 80% calcium oxide. The rest comes from organic matter that pigments the pearls in various shades Brown color.
As already mentioned, the organic substance - cochiolin - that holds aragonite together in pearls is yellow, from light to dark brown. In lamellar layers, organic matter is yellowish or light brown, and in prismatic layers it is much darker. Obviously, this depends on the different ability of the mineral-organic aggregate to absorb certain coloring pigments from the interstitial fluid in the mollusk’s body. The thermograms of pearls reveal a series of endothermic effects that record the temperatures at which organic matter burns out and its various connections with the mineral component. In black pearls, the organic matter contains a small admixture of sooty pyrite (FeS 2), which is recorded on the thermogram by a sharp exothermic effect at 350 ° C.
Water in pearls is part of both organic and inorganic components, occupying various pores and cavities in them. This is hygroscopic water. It is recorded by a decrease in the thermal curve at a temperature of the order of 100° C. There is no doubt that the pearls also contain bound water, which is included in the amino acids that make up organic matter. The total amount of water in pearls can reach 23%.
Pearls decompose when heated and dissolve slowly in acids.
Amino acid composition of the organic matter of pearls. There are 18 amino acids found in pearls. For comparison, we note that proteins synthesized by living organisms contain 21 amino acids in different combinations. The basis of the organic matter of freshwater pearls from water bodies in the North-West of the USSR, as Corago found out, is glycine and tyrosine, followed by alanine, valine, series and aspartic acid (Table 3).
Japanese researcher K. Wada, who studied the composition of organic matter in various layers of the shell of the mollusk Pinctada fucata and cultured pearls, showed that the amino acid composition of individual parts of the pearl and the shell are somewhat different from each other. Different amino acid composition of the organic matter of prismatic and lamellar pearls. In the prismatic layers, glycine predominates; in the lamellar layers, alanine predominates. Tyrosine, which ranks second after glycine in the freshwater and prismatic layers of cultured pearls, is present in small quantities in the lamellar layers of cultured pearls. It is hardly possible to talk about a sharp predominance of any one amino acid in the composition of pearls. This question is very interesting and requires further research.
Composition of chemical impurity elements in pearls. It has been most fully studied in pearls from reservoirs in the North-West of the USSR. According to Corago, it contains the following elements (in%): aluminum (0.008-0.034), barium (0.031-0.083), iron (traces - 0.005), silicon (0.003-0.120), magnesium (0.016-0.120), manganese (0.004-0.400), copper (0.001-0.003), silver (0.0001-0.0029), molybdenum (0.002-0.014), lead (traces - 0.008), strontium (0.1-0.3), antimony (0.01), titanium (0.001-0.003), sodium (0.1-0.3), tin (0.001).
The most stable contents are strontium, titanium, and sodium. Their number in brown, gray and white pearls is the same. Antimony and tin were found in only one brown pearl. The amounts of other elements, especially manganese, magnesium and silicon, are variable. Manganese is most abundant in white pearls, gray pearls have little of it, and brown pearls have even less. On the contrary, there is more silicon in brown pearls, less in gray and white ones. Magnesium is approximately equal in white and brown pearls, and somewhat less in gray ones. Almost the same amount of aluminum, barium, iron, copper and molybdenum in all studied pearls. The significant content of manganese in white pearls is noteworthy, 8 times higher than the amount in gray and 30 times higher in brown pearls. This phenomenon is explained by the fact that manganese is predominantly sorbed by the lamellar (nacreous) layers that make up white pearls, while the prismatic layers preferentially absorb silver.
Analyzing the content of chemical elements in pearls of various colors, we note the following. Brown pearls are enriched with lithophile elements, as well as silver and lead. Most gray pearls are closer in chemical element content to white pearls than to brown ones. Gray pearls (compared to white ones) contain more barium, silicon, copper, silver and molybdenum, white pearls contain less molybdenum, silver and silicon.
Saltwater pearls extracted from Black Sea mussel shells contain half as many chemical elements as freshwater pearls. E.F. Shnyukov and D.P. Demenko discovered in two pearls mined in the Black Sea the following elements (in%): magnesium (1.8-3.8), manganese (<0,0001), медь (0,0001), серебро (0,00001-0,00005), стронций (0,1-0,2), титан (0,0002-0,0005), цирконий (0,001), лантан (0,001-0,002). Последние два элемента найдены только в морских жемчужинах.
Most of the chemical elements found in pearls are associated with the life processes of mollusks, in particular with their selective ability to absorb these elements from water. Most of the microelements are found in the amino acid group of humic acids, which are part of organic matter. A significant role in the accumulation of chemical elements in pearls is played by metabolic processes taking place in the cells of the “pearl” sac.
Carbon isotope composition of pearls. The carbon isotope composition of pearl aragonite carries information about the nature of the solutions from which it was deposited in the body of the mollusk. The quantitative ratio of stable carbon isotopes 12 C and 13 C in carbonates is expressed by the coefficient 6 13 C, meaning in ppm the deviation of the 13 C / 12 C ratio of the substance relative to the same ratio in the standard. In table 4. Information is provided on the distribution of the 6 13 C value in pearls from water bodies in the North-West of the USSR.
The isotopic composition of carbon in pearls ranges from -8.7 to -12.0°/oo. It falls within the limits characteristic of 6 13 C carbon in freshwater carbonates (6 13 C = -5/-15.0°/oo). From the data obtained, we can conclude that the formation of pearls occurs with the participation of bicarbonate solutions with different carbon isotope compositions. Gray and light brown pearls, consisting mainly of prismatic layers and a thin shell composed of lamellar layers of aragonite crystals, were formed from solutions whose isotopic composition changed towards lighter. At the same time, the isotopic composition of carbon in pearls changed accordingly in the following sequence: -10.2 and - 10.8°/oo (prismatic zone) and -12.0°/oo (lamellar zone); - 8.7%o (prismatic zone) and -10.2%o (lamellar zone). The formation of a brown pearl composed of prismatic aragonite crystals initially occurred from a solution with 6 13 C = - 10.5%o, and at the last stages of crystal deposition - from a solution with 6 13 C = - 9.6°/oo. That is, the isotopic composition of the carbon of brown pearls during the process of deposition changed not towards lightness, as in light and light brown pearls, but towards heavierness. The reasons for this phenomenon need to be investigated. In this regard, the study of the isotopic composition of pearls cannot be considered complete. There is no doubt that the 6 13 C value of pearl aragonite carbon is influenced by many factors. It is not possible to take them into account now.
Isotopic composition of oxygen in pearls. The conditions for the formation of pearls and the peculiarities of the development of mollusks are indicated by the ratio of the stable oxygen isotopes 16 O and 18 O in them. It is expressed by the coefficient 6 18 O, which, as in the case of carbon, means a deviation in the value of the ratio 18 O / 16 O relative to the same relations in the standard. The distribution of the 6 18 O value in pearls from water bodies in the North-West of the USSR is evidenced by the following data:
The oxygen isotopic composition of pearls ranges from -8.2 to -20.8% O 6 18 O and falls within the limits characteristic of 6 18 O oxygen in freshwater carbonates. The average value of 6 18 O of oxygen in the studied pearls is 15.8% O and is slightly higher than the average 6 18 O of fresh water (-9.11 % O). It is very close to 6 18 O of the waters of the Northern Dvina (-15.5% o), while 6 18 O of the main pearl-bearing rivers of the North-West of the USSR (Kemi, Varzuga, Umba, Onega), from where the pearls were most likely obtained, is equal to - 9.1/-9.7%o [S. D. Nikolaev, V. I. Nikolaev, 1976]. That is, there is no direct inheritance of the oxygen isotopic composition of river water by the oxygen isotopic composition of pearls. In this case, one should assume the possibility of biological fractionation of oxygen isotopes, leading to the depletion of pearl aragonite in the “heavy” oxygen isotope 18 O. It is important to emphasize that of the solutions the most enriched in this isotope (6 18 O = -8.2%o). A mother-of-pearl layer is formed, which gives the pearl value. The outer layer of a prismatic-layered pearl, on the contrary, crystallizes from a solution with a minimum content of 18 O (6 18 O = -19.4 and -20.8 °/oo) In the same mollusk, the nacreous layer of a pearl contains more of the “heavy” isotope (6 18 O = -8.2%o) than the mother-of-pearl layer of the shell (6 i 8 O = -14.5°/oo). The transition of aragonite to calcite almost does not change the oxygen isotopic composition of the original carbonate.
Porosity. Pearls from reservoirs in the North-West of the USSR have low porosity. Moreover, the porosity of brown pearls is much higher than that of white and gray ones. It is believed that only brown pearls have a certain number of pores, concentrated mainly in the range of equivalent radii of 3-5 nm. The total porosity does not exceed 1% of the sample volume. If we take into account the small size of the pearls (a few millimeters), then their specific surface area can be considered quite significant for all samples, especially for brown pearls. This is confirmed by the presence of small pores, some of which, as Corago emphasizes, are located in the region of equivalent radii less than 3 nm, which is not measured on a mercury porosometer.
Luminescence (cold glow under the influence of radiation) is one of the important characteristics of a substance. The essence of luminescence is that many minerals placed in the path of x-rays, cathode or ultraviolet rays themselves begin to emit light. Different minerals have different luminescence, both in strength and color. It is also known that chemically pure substances usually do not glow. Impurities of other substances in the mineral are required in amounts from thousandths of a percent to several percent to cause its glow. Therefore, depending on the impurities, the same mineral in different deposits glows with different light.
Research into the luminescence of pearls has been going on for a long time. Particular interest in it arose in connection with the need to distinguish a grown pearl from a natural one, and a colored (blackened) one from an artificially grown one. It turned out that under the influence of X-ray radiation, grown pearls fluoresce more than natural ones. The nacre core of grown pearls fluoresces especially strongly. The English researcher B. Anderson explains this by saying that the core is almost always made from mother-of-pearl of a freshwater shell and therefore usually contains a small admixture of manganese salts. When irradiated with X-rays, the core produces green luminescence and, if the shell is not too thick, transmits the glow to the entire pearl. After the X-rays cease, the grown pearls exhibit a short phosphorescence. According to Anderson, cultured freshwater pearls grown in Japan on Lake Biwa (biwa - pearls) fluoresce most intensely in X-rays.
Japanese researchers G. Komatsu and Sh. Akamatsu found that dyed (blackened) pearls do not fluoresce in ultraviolet rays, while grown pearls in the same rays clearly fluoresce in yellow-red tones.
Freshwater pearls luminesce in much the same way as cultured pearls. A detailed study of the luminescence of freshwater pearls from water bodies in the North-West of the USSR was carried out by Corago. He found that the luminescence spectrum of freshwater pearls has a wide band, covering the entire visible spectral range from 360 to 700 nm. The maximum spectrum depends on the nature of the pearl. Thus, in white (jewelry) and gray pearls it is in the region of 485-495 nm, in brown pearls - in the region of 525 nm. The luminescence spectrum of Japanese cultured pearls is close to the spectrum of domestic freshwater pearls, but is more intense.
The results of the studies allowed Corago to conclude that the luminescence of pearls is due only to organic matter, which differs in composition in the prismatic and lamellar layers. The intensity of luminescence depends on the size of the pearl studied - the surface of its glow and the thickness of the pads of organic matter separating the crystals and layers of aragonite. The thinner these spacers are, the fewer obstacles the ultraviolet rays will encounter as they pass deep into the pearl and the deeper they will penetrate into it, causing luminescence of the layers of organic matter encountered along the way. In pearls with significant layers of this substance, the luminescence intensity is low. In brown pearls, only the surface layers luminesce; Sea pearls luminesce in ultraviolet rays with a bluish, white, greenish color.
X-ray examination. X-ray studies of modern freshwater and saltwater pearls have confirmed that aragonite predominates in them. All diffraction patterns clearly reveal intense reflections (3.36-3.38; 3.26-3.28; 2.71-2.72; 2.67-2.68; 2.46-2.47; 2. 36; 2.31-2.33; 1.965-1.967; 1.805-1.806, 1.735-1.720 A) The difference between the diffraction pattern of pearls and that of synthetic aragonite lies in the presence of additional reflections on it (3.54-3.55; 2.05; 1.847; 1.627-1.637; 1.610-1.614 A), indicating the presence of some other compounds in the pearl composition .
Pearls from 200 and 300 years ago also have an aragonite composition. The weathering processes that led to the change in some areas of the pearls to a powdery state did not affect their mineral composition.
The results of an X-ray study of freshwater pearls from a gold bracelet (1st century BC - 1st century AD) found in the Simferopol area are different. It turned out that freshwater pearls from 20 centuries ago are represented mainly by calcite with a very small amount of aragonite. The interplanar distances of sea pearls from mussels caught in Feodosia Bay indicate that they are composed of aragonite. According to the X-ray study of Black Sea pearls carried out by Shnyukov and Demenko, it consists of aragonite with a small admixture of clayey substance of montmorillonite composition. An admixture of calcite was found in the mother-of-pearl layer of the shells; Calcite predominates in the outer layer of shells.
An ordinary grain of sand, falling into a sink, turns into a beautiful pea in 12 years. Raw pearls are unique both in origin and in their properties.
Magical properties of the stone:
- When admiring a gem, a person calms down, relaxes and becomes peaceful.
- Wearing a stone helps to get rid of bad thoughts, protects you from dangerous financial transactions and dishonest partners.
- Thieves will never get into a house where there is this beautiful pea.
- Pearls strengthened the power of rulers back in the Roman Empire and added wisdom to them.
- A gemstone amulet helps to establish relationships with others, eliminates vanity and excessive arrogance.
Note! Pearls serve the owner. You cannot buy a stone that someone has already worn. You can pass it on by inheritance.
Characteristics of pearls: a round-shaped stone made of calcium carbonate and conchiolin, with a pearlescent sheen of various colors.
Who is suitable according to their zodiac sign: compatibility in astrology
The magical meaning of pearls is different for each representative of the zodiac sign.
Who does the gem suit according to the horoscope:
| Zodiac sign | The influence of pearls |
| Cancer | Normalizes blood pressure. The person becomes calmer and more balanced. |
| Taurus | Relieves depression. Helps to end the dark streak in life. |
| Scales | It calms pride and helps people win favor. Helps to achieve family happiness. |
| Sagittarius | Helps maintain balance of strength and energy. |
| Aquarius | Develops the ability to communicate without conflict. Makes women more gentle and caring. |
| Capricorn | Promotes an objective assessment of situations, gaining peace. |
| a lion | It will create discomfort in relationships with others and contribute to disruption of mental balance. |
Note! For Taurus, Pisces and Gemini, pink polka dot jewelry is suitable. Black pearls are preferable to wear for Aquarius and Scorpio.
What color and what it looks like: types of stone
Pearls can be sea or river. The sea gem is characterized by a round shape and a smooth surface. Freshwater stone is irregular in shape and does not shine as brightly as sea stone.
What pearls look like, their types and what color they are depends on:
- From what the mollusk ate and how healthy it was.
- On the quality of the water where the mollusk lived and its temperature.
- On the duration of the ripening of the gem.
Varieties of pearls differing in color:
- White pearls symbolize elegance, wisdom, purity, dignity and faith. For thousands of years, a necklace made from this gem has been considered a wedding accessory, emphasizing the sanctity of marriage.
- Pink is a gem whose shades can range from soft pink to bright purple. A symbol of tender love, embodied in femininity, grace and modesty.
- Jewelry made from lilac pearls endows its owner with magical beauty, grace and attractiveness.
- Only wealthy people can own gold gems; it gives the highest status in society and is the height of luxury.
- Black pearls are called conventionally; in fact, they have many shades: from a blue tint to emerald dark green. The stone complements the female image with sexuality, individuality and courage.
Note! There are also cultured pearls - artificially grown pearls.
How much does it cost: price
Pearl peas are the most expensive gems.
How much a pearl product costs depends on:
- Evenness of the surface of the gem.
- Ideal form.
- Pea size.
- Origin.
- Brightness and radiance of shine.
Note! Sea peas are of better quality, their price is much higher than that of river peas.
Products and decorations made of stone and its use
The use of peas of various palettes is used by jewelers in jewelry for women and men.
There is a classification of pearls by shape:
- Sphere.
- Hemisphere.
- A drop.
- Baroque.
- Semi-baroque.
Note! In jewelry production, a gem is classified by its brilliance - from “A” to “A.A.A.”
This gemstone can be combined with any metal.
Medicinal properties: do they exist?
Pearls can warn the owner about the onset of illness by changing their shade.
Healing properties of the gem:
- Helps restore memory.
- Treats liver and kidney diseases.
- Helps with hypertension.
- Strengthens the central nervous system, normalizes mental processes.
- Helps get rid of eye pathologies and infections.
Note! Pearl water is prepared from the gem, which cleanses the body. Left for 12 hours, it gives it healing properties.
How to distinguish a fake: checking for authenticity
A gemstone can be natural, or it can be cultivated or artificially created.
How to determine the authenticity of a gem:
- Fakes have a low price.
- A genuine stone is elastic and can bounce when dropped.
- If you rub natural gems against each other, they slip easily.
- If you try to hit your teeth with a natural gem, you will hear a creak.
Note! Artificial species often have better physical characteristics.
Mineral deposits
Stone deposits by color:
- On the shores of India, the Bahamas and the Gulf of California there are pink gems.
- In the Panama basin they are golden.
- In Mexico they are red.
- On the islands of Tahiti - gray.
- On the shores of Japan and in the seas of Australia - white.
- In the Red Sea, Sri Lanka and the Persian Gulf - yellow.
Note! River peas are found in water bodies of Germany, America, China and Russia.
Care and storage
During storage you should avoid:
- High humidity.
- Acid exposure.
- Dry stale air.
Note! The mineral is of organic origin and therefore requires special care.
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