Cultured pearls: varieties and cultivation process

Pearls are one of the most beautiful minerals of animal origin. Gift of the sea, which has been mined and used since ancient times. At all times, pearls were considered the personification of purity and beauty. And jewelry made with pearls makes the image feminine and delicate.

In the XIII century, technologies appeared in China that made it possible to facilitate the process of mining a precious stone. Initially, it consisted in attaching clay balls, bone fragments and even miniature Buddha figurines to the mollusk. But this method produced small and uneven pearls. Nevertheless, until the 17th century, China remained the only country to cultivate pearls. In the same century, they began to grow the mineral in Japan using Chinese technology.

Due to the differences in the starting material, the pearls turned out to be quite large and even. Later, in the XX century, the technology of pearl cultivation took shape completely.

Let's take a closer look at what cultured pearls are. The cultivation process itself involves the creation of the necessary conditions for the shells and the artificial stimulation of the mollusk. To obtain certain types of gemstones, experts resort to such tricks as coloring the finished product, as well as fixing the irritant in the shell in a special way to obtain a pearl of the desired shape.

Currently, the extraction of real pearls is not carried out. In the last century, fishing activities were prohibited as part of the program for the conservation of the mollusk population (since when the shell is opened to examine it, the mollusk dies).

There are only two differences between pearls of "spontaneous" origin and pearls grown on a farm.

1. In the targeted production of pearls, the process of getting a "foreign body" into the shell is controlled by a person. In nature, this process is random.
2. Pearls grown under human supervision have the correct shape and smooth surface. Of course, if these qualities are not a feature of a particular type of mineral.

There are also some chemical and physical differences between the two types of gemstones.

1. The stone grown on the farm, when worn, reaches a temperature close to that of the human body. But absolutely natural stone will remain cold.
2. Cultured pearls are denser than those found at sea.
3. The cut of sea pearls has a shell-like appearance, and the cut of a cultured gem will depend on the nature of the core.

The value of pearls has always attracted the attention of scammers. And with the proliferation of cultured beads, they began to be counterfeited as well. But there are a number of signs that will allow you to identify a fake.

1. Real stones never have a perfectly smooth and even surface.
2. Elasticity index: if a fake is "dropped" from a small height onto a hard surface, then it will simply roll, while the original will "jump".
3. On the Mohs scale, pearls have a density of 3-4 points. This means that it is not easy to scratch. If this happens, then the scratches go into the mother-of-pearl layer. If you scratch a fake, only the top coat of paint will be damaged.
4. Natural pearls are very difficult to dye. The technology, which involves dyeing beads, is based on the principle of dyeing all layers of mother-of-pearl. When such a bead is exposed to heat, the color will not change. But the fake will change its color.

For information on how to distinguish natural from synthetic pearls, see the next video.

The pearl formation process is a reaction of a mollusk to an external stimulus located between the mantle and the shell valve or directly in the mantle (fold of the mollusk body wall).

The outer layers of the shell are formed from minerals that are secreted by the outer part of the mantle. She also produces nacre, which covers the inside of the shell. This feature is used in the formation of a pearl.

If the stimulus is completely immersed in the mantle, then a so-called pearl sac is formed, in which the mollusk gradually envelops the stimulus. This is how spherical beads are made. If the stimulus is not immersed in the mantle, but is fixed on the inner layer of mother-of-pearl, then the mollusk begins to process only the part accessible to it.

There are several technologies for introducing an irritant into the shell without damaging the mollusc.

1. Linnaeus technology. He made a small hole in the sink through which he placed a small limestone ball. He did this with a silver wire.
2. Another option involves creating a thin gap between the shell valves. This is done using special forceps.

Pearl production can be classified:

1. by technology;
2. by the composition of the water.

A distinction is made between non-nuclear and nuclear technologies.

With this technology, a piece of mother-of-pearl or the outer shell of the shell itself is used as an irritant. In this case, the bead is completely organic. This technology is followed by most breeders.

This technology uses a small ball as an irritant. Based on the fact that such jewelry is not entirely of natural origin, their price is much lower.

According to the composition of the water, freshwater and sea water are distinguished.

Each of these methods has its own advantages. Marine molluscs are capable of producing only one bead in a few years, while most freshwater molluscs can produce several beads.

There is also a difference in the size of the beads: due to the fact that only one irritant is located in sea mussels, their pearls are much larger than those given by freshwater mussels. Jewelry of marine origin can be up to 20mm, while the average for freshwater jewelry is 5-12mm.

Despite the fact that growing pearls at home is a painstaking job, this hobby has gained popularity in Japan. They even sell special kits with akoya oyster, special aquarium and food. For home breeding, it is recommended to take unpretentious mussels in care. Pearl types such as Kasumi and Mabe are very common for breeding. They owe their popularity to a relatively quick result.

To choose the type of oysters for breeding, you need to familiarize yourself with several indicators:

1. how much space is required for one oyster;
2. what are the permissible indicators of impurities in water;
3. when and how to feed the mollusk;
4. at what age can the stimulus be introduced;
5. how long does it take for a pearl to form.

Taking into account the percentage of mollusks death after the stimulus is attached and the low probability of the formation of even one pearl, to get at least two or three beads, you will need to purchase at least two to three dozen oysters. To place them, you will need an aquarium of 100-150 liters. In order for the mollusk not to die, it will be necessary to regularly measure the temperature of the water, the amount of salt and impurities.

Permissible values ​​of impurities in water depend on the type of molluscs (river or sea). Depending on where, in what conditions and what age the oysters are grown, impurities are removed or added from the water. For advice on this issue, it is worth contacting a specialist - biologist.

Molluscs feed on organic sediments, algae, and small organisms. On farms that are set up in open water, there is a whole technology for balanced feeding of shellfish. If, at home, it is possible to place the oyster in a natural sea lagoon, then this will greatly facilitate the process of feeding the mollusk. Home breeding feed can be purchased from specialized farms.

The introduction of a stimulus is also an individual indicator. The readiness of a mollusk for a foreign body is determined by its age, the species to which it belongs, and the conditions of detention.

There is no specific date when the pearls will be formed. Different types of shellfish take different amounts of time. The fastest time for the formation of a jewel is 2-3 years. The longest form of black pearls is formed - 9 years. A small pearl of home origin will take 1.5 to 4 years to form.

There are several features that affect the results of farmers' work:

1. the death of the mollusk causes a sharp drop in temperature;
2. when the stimulus is planted, 10-40% of all mollusks die;
3. the younger the mussel, the more active the formation of the nacreous layer will occur;
4. There are three main indicators by which the conditions for keeping mussels are regulated: the temperature of the water, its chemical composition and the acidity index.

The finally formed jewel is classified according to two parameters:

• by form;
• by grade.

Several varieties are distinguished in shape.

• Rice. An elongated gem with a smooth, even surface. The central part is rather wide, and towards the ends the shape gradually tapers.
• Sphere. Pearls that look like a perfectly flat sphere.
• Hemisphere. Jewelry of this variety looks like a sphere slightly flattened at the top and bottom. The same kind of pearl, for the production of which the Japanese researcher K. Mikimoto (a variety of Mabe) received permission.
• Baroque. Pearls that have a spherical shape, but due to various asymmetric protrusions, are not classified as either a sphere or a hemisphere.
• Semi-baroque. Jewelry is also spherical. A distinctive feature is the stripe-shaped protrusions.
• A tear. A pearl in the form of a drop or tear. They are considered the rarest. They are often encrusted in tiaras and earrings.

What kind of jewel takes on depends primarily on the type of pearl mussel used.

There are more than 25 types of cultured pearls in the world. Each plantation strives to develop an exclusive variety unknown to anyone. The most common varieties include several types.

• Perhaps the most famous variety is akoya (akoya). The name of this species comes from the name of the mollusk. It is produced on several islands in Japan, Vietnam and China. Despite the fact that this type of pearl is produced in three countries, only pearls grown in Japan are considered classics. Pearls are distinguished by their perfect shape and bright luster. The diameter of a standard bead is 10 mm. Their colors range from white, gold, cream to light green and light lavender.

• Souffle. The species received this name for its resemblance to the French dessert of the same name. In the production of jewelry, a special material is used as a core that absorbs water. Outwardly, jewelry of this type is very similar to raisins. Their colors range from pink to purple.

• Pink pearls of conch. These are extremely rare and expensive jewelry. Their price is due to the fact that the bead cannot be obtained without killing the clam. This makes the cultivation process unprofitable, and their natural extraction is prohibited. They look like small bright pink beads of irregular shape.

• Black Pearl. It is mined on the island of Tahiti and the Philippine Islands. The largest bivalve mussels in the world are used in its production. Usually the beads have some color.

• Types of pearls of the South Seas. This name unites the territories of Oceania, Australia, and the islands of the Indian Ocean. Pearls can be of several varieties.

• Edison... It is produced in Japan and the USA. This freshwater freshwater pearl is characterized by large size, smooth surface, perfect spherical shape and bright color. According to its indicators, it is no different from the sea.

• Mabe. Beads of this type have a hemispherical shape, which is why they are very popular among jewelers. It is mined in Japan and Southeast Asia.

• Biwa. Beads of this type have an oblong shape. In length, they reach 3-4 cm.This is a freshwater pearl that began to be bred in Japan on the lake of the same name. Later, its production was mastered in China and Mexico.

• Kasumi like. Another species that has become widespread in Japan. It is a freshwater species with an irregular sphere shape and delicate hues. Due to the fact that the total volume of pearl production is not high, it is one of the most expensive.

Processing is necessary in order to give the pearl a presentable appearance before being sold. It implies a number of effects on the material.

• Whitening. The procedure is used to give the beads an even color or to correct the color towards lighter tones.
• Dyeing... This technology allows you to "hold out" the color of the jewel to the desired shade. It is considered harmless to the structure of the pearl.
• Filing or sanding. It is used when there is a need to make the surface of the jewelry smooth. Previously, grinding was done with a diamond. Now they use white coral powder or alabaster. Increasingly, direct intervention is being replaced by chemical treatment.
• Irradiation - procedure for dyeing the pearl core. This is done using silver nitrate and ultraviolet irradiation.
• Polishing... It is used in cases where the pearl becomes tarnished. Most often this occurs through direct interaction with the human body or from improper use.

When interfering with the structure of a pearl, it is impossible to predict the consequences. The result will depend on the conditions in which the particular jewel was grown.

Like any other jewelry, pearls require special treatment and good care. The product will retain its original appearance longer if you follow a few rules.

• Do not use cream before putting on jewelry. Contact with chemicals can damage the outer layer of the pearl, and it will lose its luster and brightness.
• Before returning a jewel after wearing it, be sure to wipe it with a dry soft cloth.
• Wrap pearls in a soft cloth for storage.
• The storage room should not be too dry.