How diamonds are cut. Jewelry diamond processing Corridor line 95 for diamond processing

Yes, yes, dear reader. “Zvezdochka” is not only known for steamships. Since the beginning of the 2000s, the company has launched production of cutting rough diamonds into polished diamonds. As many probably know, a diamond, with all its other technical advantages, only becomes “the girl’s best friend” when it turns into a diamond. Today's photo report tells us about the path he will have to go through.

It all starts... You guessed it with a hanger. Third-party visitors who have passed the hard materials processing station (as cutting is officially called) are asked to put on a robe and are assigned at least two accompanying persons: a workshop worker who acts as a tour guide and an employee of the economic security department. Trust, as they say, but verify.

Now we are ready to get acquainted with the workshop. The first point on the route is a storage room for raw materials.

This is where the raw materials—uncut diamonds—come. Here they are processed: they are counted, weighed, checked for compliance with shipping documents, each stone is entered into an electronic accounting database and a unique route map is written out for each stone. In this route map, folded into an envelope, the diamond will travel through the areas.

This is done using a computer markup system. The installation scans the diamond and forms its three-dimensional digital model. Using this model, the technologist will decide how many diamonds will come out of a particular stone and what shape they will have. The principle of combining the value of the future diamond and minimizing waste is at the forefront. The program not only allows you to visualize the diamonds hidden in the diamond, but also gives their approximate value. The classic KR-57 cut usually has the highest cost. Unfortunately, not every natural stone allows you to achieve exactly this shape with maximum use of raw materials.
The cost of this diamond placer is $3,560.

This stone will produce one diamond, but larger. Its cost will be just under three thousand dollars.

And of this - two, but smaller and, accordingly, for a more modest pocket.

Before leaving the site, the stones are glued onto special mandrels for subsequent processing. This rack is heated in an oven so that the glue holds the diamonds securely.

From the UZTTS the stones go to the sawing and peeling area. In the old days, sawing stone was done mechanically using a bronze disc coated with diamond.

Today, the majority of sawing is done with a laser. The installation operator has the ability to visually monitor the process.

Laser cutting, firstly, is faster. The sawing process, depending on the size of the stone, can take from five minutes to half an hour. Secondly, the laser cut thickness is only 2 microns, which significantly saves rough diamonds.

However, some stones that have high internal stress are dangerous to cut with a laser. And then sawing is carried out the old fashioned way - with a bronze disc.

After sawing, the diamonds, each of which is packed in a separate sheet-envelope with a bar code, a list of all operations carried out with the stone, the names of each of the workers whose hands touched the stone, and other information, are sent to the cutting department. This is where the diamond will turn into a diamond.

Diamond cutting is carried out on a rotating cast iron disc coated with diamond. When exposed to the mechanical action of a grinding disc, carbon changes its structure. A thin graphite film is formed on the crystal, which wears off, bringing the diamond to the desired shape.

The diamond is fixed into the seat of a special hand-held device - a collet.

Using adjusting screws, the cutter changes the position of the stone in the collet so that the diamond rests on the disk at the desired angle. This is how a shapeless stone acquires a platform, edges and wedges.

It also happens that the stone falls out of the collet mount. The rotating disk can send it on a “journey” around the area. Then the command “loss” is heard and the unlucky cutter goes in search of the lost diamond. Despite the fact that each cutter's place is equipped with special stone catchers, it happened that the search took a very long time.

In general, when the signal “loss” is signaled, the entire production turns into a “submarine”, from which, as you know, you can’t escape. Exit outside the site is stopped while searching for the lost stone. In the entire history of the work, only one diamond was considered completely lost. But he was found too. Having flown out from the cutter’s disk, the stone “stuck” to the wall, where it was discovered only a few years later.

When grading, cut stones are compared to these standards.

The color and imperfections of a stone are almost the decisive factors in its price. The price of stones of similar weight and cut, but different in color, can differ significantly.

From the evaluation site, the diamond, through another storeroom, is sent far away - to the Smolensk Gemological Center. In Smolensk, the diamond will receive a certificate and turn into a commodity. It can be legally sold, given as a gift, passed on by inheritance, or simply “languished” over it, like Pushkin’s Koschey over gold.

The cost of this certified diamond is about one and a half million rubles.

All movements of stones outside the workshop are carried out by special communications convoys. Inside the workshop, control over the movement of stones is carried out by the economic security department of the enterprise security service. The accounting of stones is organized in such a way that even after many years it is possible to completely restore the history of each of them. Where it was mined, how and by whom it was purchased for processing, who and when touched this stone, what manipulations were performed with it, where at a particular point in time this stone was located while it was at the factory.

Jewelry production is technologically closely related to cutting. Gold, silver, rings, earrings, rings, pendants... Yes, yes. We have them too.

The production of serial jewelry begins with waxing.

In special rubber molds, the worker casts wax “prototypes” of future rings or earring parts. A casting mold is assembled from these wax blanks. Here it is called “herringbone”. The blanks are glued to the wax rod one to one, like branches on a Christmas tree. The collected wax tree is sent to the foundry area. Here it is filled with a molding mixture, mainly consisting of gypsum with special additives, and placed in the oven for several hours. The casting mold - flask - hardens, the wax is melted out of it, leaving an empty space of the desired shape.

Molds for custom-made piece jewelry or new designs are made on a special milling machine. Here the machine cuts them out of wax according to the loaded 3D models. The customer has the opportunity to “touch” the product before it is made in metal.

At the next stage, the plaster mold will be filled with gold alloy. Precisely an alloy. Alloying additives are introduced into gold of the 999th standard, bringing it to the “commercial” 585th standard.

Everything happens in this foundry furnace.

Ship steel comes to the plant in sheets, and jewelry gold comes in kilogram bars. It looks like a pure chocolate bar.

An ingot is a practical form for storing and transporting gold, but handling ingots is inconvenient. On this machine, gold entering jewelry production is rolled into strips into gold foil.

Many diamonds already have perfect shapes and optical properties by nature, but the initial appearance of the stone cannot reveal the full beauty of the diamond. Large stones have imperfect facets, since small diamonds often have quite decent facets. Often crystals have minor damage that is noticeable and spoils the overall appearance of the stone. Sometimes crystals get damaged as a result of mining. Working on the shape of the diamond is the first stage of processing, the second stage is making a special setting for the diamond.

Often it is the stone that is adjusted to the frame and determines its shape. They began to process stones from ancient times, however, at that time it was at a too primitive level and everything came down to grinding. Therefore, the stone did not fully reveal its optical properties, and external signs remained noticeable. Typically in ancient times, gemstones were used for pendants. Sometimes jewelers were engaged in processing stones for the high priests, then the stone must have certain characteristics, a color scheme, and then the frame was adjusted to it.

Among all the cutting methods, the most ancient one, which is still used to this day, is “cabochon”. It is used in Russia, the USA, Canada, Mexico, Cuba, the Dominican Republic, Brazil, European and European Union countries (Bulgaria, Great Britain, Spain, Germany, Greece, Italy, Poland, France, Croatia, Czech Republic, Montenegro, Austria and Switzerland), and also in Asian countries (Australia, India, Thailand, Singapore, Vietnam, Indonesia, Malaysia, Philippines, Iran, China), Israel, African countries (Tunisia, Egypt, Libya), states of the Caucasus region (South Ossetia, Abkhazia, Armenia, Azerbaijan , Georgia), Turkey, the countries of the Baltic region (Estonia, Latvia, Lithuania, Finland), the countries of the former USSR (Belarus, Ukraine, Moldova, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan), regions of Russia (Moscow, St. Petersburg, Dagestan of the Russian Federation, Ingushetia, Chechnya of the Russian Federation, North Ossetia).

This method allows the stones to be given a round shape. A similar processing method was used back in the days of Ancient Rome. It so happened that emeralds, garnets, sapphires and rubies were processed using the cabochon method. The dark red garnet was most often processed and therefore, over time, this particular stone began to be called a cabochon, and it was very often used for brooches. In ancient times and before the 15th century, many people believed that it was impossible to process diamonds at all, since their shape was too hard, so only the layer of resin was removed from the stones. Stones from India had this coating.

Later, another method of polishing diamonds was invented - using metal discs. Initially it was believed that the author of the invention was Louis de Berkan, but Henri Polak later denied this fact. Therefore, there was an assumption that the method was invented in India. Of course, Indian craftsmen had little idea that using this grinding method they were discovering the optical properties of diamond. Grinding techniques developed very slowly and by the 16th century only two forms of cutting were known to jewelers - tip and table. With the first type it was much easier for the craftsmen than with the second, since here they only needed to improve the natural forms of the stone. As for the second method, the first thing that was needed was that the stones should be large in size. Sometimes a saw was used for this work.

The next method of diamond processing was invented by Cardinal Mazarin, at least he is credited with this invention, although there are hypotheses that the method first appeared in India - rose cutting. This method is used only for processing small diamonds. There are six variations of this cut: Dutch rose, half-Dutch rose, Antwerp rose, double Dutch rose, triangular rose, briolette.

The next method - diamond cutting - is believed to have been invented in the 17th century in Venice. Stones that undergo this type of cutting have 32 facets. This type of cut has tangible advantages over others, so stones that were processed using the rose method were often given a diamond cut again. Another type of diamond cut is a modified shape. This method is optimal when it is necessary to preserve the weight of the stone as much as possible without disturbing the optical effect in any way; this type of processing is often called “Ker’s star”. This method was invented in the USA, and there it gained great popularity, due to the fact that diamonds were marked by an unusual play of light; the stone changed its appearance with every movement. In addition, at the beginning of the last century, another type of cut was invented in the USA, which was named in honor of Queen Victoria’s 60th birthday - “jubilee”. Ladder cut is often used for colored diamonds. Therefore, the structure of a processed diamond consists of a tablet and several rows of faces.

This method is used to fully show the inner beauty of the stone. Moreover, if the stone is of a dark shade, then its size is significantly reduced so that the flow of light does not disappear completely, and vice versa, if the stone is transparent, then its height should be large so that the light appears as much as possible. Recently, high-quality diamonds have been treated with the so-called emerald cut - in this case, all proportions must be correct.

A mixed cut is a step cut added to a diamond cut. Regarding the light effect - it is too weak, although the appearance is significantly improved. The number of edges depends on customer requests. An attractive cut of this method is the French cut. In this case, the effect of light can be different; for example, ruby ​​and sapphire can be cited; in fact, they are one mineral - they are just its varieties. Regarding the effect of light, a red ray passes through a ruby, and a blue ray passes through a sapphire, and then these stones have different optical properties.

In 1961, profile cutting began to be used. When processed by this method, using a special saw, diamonds are cut into plates, the thickness of which is 1.5 mm. Then these plates are processed - the upper side is polished, and the lower side is covered with special grooves. Typically, such plates are marked by their unique shapes and from them jewelers make a variety of jewelry of non-standard shapes, the original name of the cut is “princess”. Today, people spend money on diamonds in all countries: Australian dollar, Belarusian ruble, British pound, European currency, Kazakhstani tenge, Canadian dollar, Chinese yuan, Lithuanian litas, New Zealand dollar, Russian ruble, Singapore dollar, Ukrainian hryvnia, Swiss franc, Japanese yen, US dollar and others.

Processing rough diamonds into polished diamonds is not difficult from a production technology point of view, but it is nevertheless extremely difficult human labor. The basic operations have remained virtually unchanged for several hundred years and are performed manually. However, all of them are constantly being improved in the direction of increasing the productivity of diamond processing and the quality of manufactured diamonds, as well as in the direction of creating new shapes and types of cuts.

When processing diamonds, you must rely on special knowledge, have patience, perseverance, and under no circumstances rush into making a decision regarding a particular future diamond. The decision on how a diamond should be cut is made based on its natural shape, taking into account the stone's internal crystal structure, inclusions and flaws, so diamond production You constantly have to make a choice between the largest possible size and the highest possible quality of diamond. There are no strict rules on this matter. Nevertheless, despite all the difficulties, a perfectly cut diamond must emerge from the hands of the cutter.

The technology of processing diamonds into polished diamonds means the sequential performance of certain operations with diamond crystals. Such operations include: pre-production research of diamond crystals, their marking, sawing(splitting), sanding(rough peeling) stripping(turning), cut, polishing, flushing And grade.

As scientific and technological progress develops and cutting equipment improves, the content of the operations themselves may change, but their essence and name will most likely remain the same. For now, the main technological principle remains that diamonds are processed only with diamonds, although laser machines have long been introduced into the practice of their processing, which perform some operations more efficiently.

Pre-production analysis carried out to determine the technological direction of diamond processing. Here, sorting is carried out according to the shape of future diamonds, crystals are determined for sawing (single or multiple), splitting or polishing; the features of each crystal are determined, stressed and defective crystals are identified, the nature and location of natural defects, etc. Essentially, at the pre-production analysis stage, a forecast is made of the weight of the finished diamond, the main geometric parameters, evaluation characteristics and cost of the future diamond.

Today, new generation cutting factories use modern technologies in the analysis, optimization and planning of diamond cutting. Computer systems for simulating diamond cutting help the technologist (cutter) to assess the possibility of a diamond and plan its processing. The system provides an instant analysis of the rough diamond and shows how it can be turned into the optimal diamond. Next, after choosing a cutting method (shape), you can set parameters for applying laser markings. The size of a diamond is an extremely important factor in the value and cost of the finished stone, so weight loss at each stage of cutting and polishing is carefully monitored by the technologist (cutter) who controls the processing process.

At marking lines are applied to the crystal, forming a sawing or splitting plane, and in the case of polishing, the plane of the diamond platform is applied. The main goal of marking is to obtain a diamond or combination of diamonds with the maximum value.

In progress sawing or splitting, the diamond crystal is divided into parts, which, according to the plan of the technologist or marker, determine the optimal use of rough diamonds. This often removes natural defects in the diamond, which increases the value of future diamonds. The technological process itself is quite labor-intensive and consists of several sequential operations that require attention and exceptional accuracy. Further work with the resulting semi-finished products and the final yield of diamonds largely depend on how these operations are performed.

Process sanding (rough peeling) is the removal of excess mass of the crystal. This operation is used when processing irregularly shaped crystals and crystal fragments when it is impossible or impractical to saw or split them. As a result of grinding, a workpiece (semi-finished product) is obtained, suitable for use in the operations of preliminary application of edges and roughing. Typically, this operation begins immediately after pre-production analysis, but can also be performed after sawing or splitting crystals of complex shapes.

Rip off Diamond processing is considered one of the most critical operations in the entire technological cycle of diamond production, on which the utilization rate of rough diamonds largely depends. During roughening (grinding), the basic shape of the future diamond is made. Peeling can be carried out in one stage or in several, when it is divided into roughing and finishing.

Cut quality - This is one of the most significant parameters when evaluating a diamond. Diamond cut, i.e. Applying facets at a certain angle relative to each other allows the diamond to refract light rays as much as possible. The bevel is obtained by friction against a grinding wheel (diamond disk), and linseed oil is used as a grinding agent. First, the large smooth facet on the top of the stone is removed - the platform. Then the main edges are applied from below and this cone-shaped part is called the pavilion. Next, the facets on the top are sharpened - this is the crown. Then additional edges are applied on the pavilion, then again on the crown. Each facet requires adherence to exact dimensions, shape and angle. The stone is also surrounded by a faceted belt - a girdle, and below, in the very bottom of the pavilion, a culet (spike) appears, parallel to the platform. Cutting itself is the application of a platform, edges and wedges to a turned workpiece in a certain sequence, observing the basic parameters for cutting.

Diamond cutting - applying the main edges of the bottom

Operations cuts And polishing are combined and carried out on the same cutting disk, the parts of which are carved with diamond powder (paste) of different sizes. Cutting itself is the application of a platform, edges and wedges to a turned workpiece in a certain sequence, observing the basic parameters for cutting. Polishing ensures a high surface clarity of the diamond and, therefore, a high light reflectance from its surface. Cutting and polishing operations are the most labor-intensive and critical in the overall technological process of diamond manufacturing.

Diamond cutting and polishing

Flushing diamonds is the final stage in the production cycle of their manufacture. The purpose of rinsing is to remove manufacturing dirt and oils from the surface of the diamond. Flushing consists of several sequential operations. In this case, a washing solution based on concentrated sulfuric acid with the addition of a certain amount of potassium nitrate, distilled water and pure alcohol is used. The diamonds are first boiled in a cleaning solution that removes remaining oils and dirt, and then they are rinsed repeatedly in distilled water and dried with alcohol. Only then do diamonds turn out clean and acquire their marketable appearance.

Further diamond appraisal consists of determining their mass in carats, sorting by size and weight groups and cut shape, determining the color group and defect group and the quality of finishing in accordance with the Russian industry classification or one of the international classifications. The assessment is carried out by experts.

Without processing, the mineral is not particularly valuable, and they ask for no more than a hundred dollars. But a diamond made from diamond costs 4-10 times more.

The cost is also affected by the type of cut, which can be:

• round;
• fantasy.

Before processing, an oblong diamond takes on shapes called:

• marquis;
• drop/pear;
• oval;
• heart.

Stones, whose natural appearance had almost ideal outlines, receive one of the following forms:

• emerald;
• usher;
• radiant;
• princess.

Processing diamonds into round brilliants is a labor-intensive process that requires strict adherence to proportions. This causes the high cost of the round product.

How diamonds become diamonds

The gems to be processed must initially be of good size. The future diamond, that is, an uncut diamond, weighs 40-60% more than after finishing work on its creation.

People learned to work with precious stones long ago, but the stubborn crystal succumbed to them only in the 15th century. Diamond processing has always been a painstaking task, requiring several stages, during which numerous methods of work were tried.

Diamond uncut:

• polished by rubbing one stone against another;
• hammered into crumbs used to coat metal discs;
• sawed;
• acquired edges and planes in a certain quantity.

Diamond processing methods

The question of how diamonds are made has two answers: manually and using a laser.

How to make a diamond from a diamond by hand:

1. Splitting. Following the lines that were made by the specialist during the inspection, small cuts are made on the stone placed in the holder with the same mineral. Afterwards a split occurs with a blow.
2. Sawing. At this stage, the stone is attached using limestone or gypsum to a copper head, which is clamped in a special cutting tool. For cutting, a thin disc is used, lubricated with oil mixed with diamond powder. The process speed is approximately 1 mm/hour.
3. Adding roundness. The mineral becomes round, making it look like a diamond. Processing is carried out using another stone.
4. The crystal is fixed in the grip of the grinding machine, the quadrant, so that a precise angle is obtained in relation to the grinding disc for applying the bevels. The discs, usually steel, are lubricated with a special paste or oil mixed with diamond powder.

Technologies are constantly improving, new ones are replacing old ones. This is why some diamonds are laser cut.

When choosing this method, each stage of the formation of the future diamond occurs using laser systems. A crystal classified as jewelry is assessed by a specialist who determines the processing method. The cutting lines are drawn using a laser. Then comes the turn of cutting and cutting, naturally, with a laser.

Laser processing allows you to give stones the desired shape without taking into account their direction when fixing. The negative point is significant loss of diamond mass, which does not happen when processing manually.

Despite the attempt to make working with precious stones easier, only a talented craftsman can create a masterpiece from them, and only with his own hands. Usually several people work with one stone at once. Each of them is involved in a certain stage, and the two of them work together to shape the diamond.

About fakes

Attempts to create an artificial diamond began in 1797, but they were crowned with success only in 1956. Over the decades, technology has improved so much that it can be difficult to distinguish an artificial stone from an original one. Some imitation diamonds are so beautifully crafted that only those who know what a real diamond looks like can tell the difference between them and the original.

The most common “fake” is called . The second stone that imitates a crystal of natural origin is moissanite, which can only be distinguished by those who know how to verify its authenticity. The third option is asha. What gives it its shine is a layer of carbon atoms, that is, what a real stone is made of, which makes identification by eye a difficult task.

Growing artificial diamonds using high temperatures and pressure, invented in the 1950s, produces almost natural crystals. This is explained by the fact that natural stones appear under similar conditions, but over a longer period.

Pebbles that do not have time to go through the full growth cycle when they hit the earth's surface require additional exposure to temperature and pressure in laboratory conditions. This allows them to become full-fledged diamonds, slightly “modified” by humans. After additional procedures, they become completely ready to be turned into a diamond.

Authentication

Sometimes the question arises about how to check a diamond for authenticity. After all, its high cost is an excellent reason for creating fakes and various imitations passed off as a real crystal. You can do this with the help of a specialist or yourself, at home.

How to determine the authenticity of a diamond:

• According to the rudinist- a narrow boundary dividing the faceted crystal into upper and lower parts. It should be matte. Transparency indicates artificial origin.
• Hardness. Real diamond leaves marks on glass surfaces. It also scratches other minerals such as sapphires and rubies. The only exception to this method is moissanite, which has a hardness similar to diamond.
• Glitter and refraction of light. A real diamond sparkles, but not as much as moissanite. A natural crystal differs from fiant and zircon in its light refractive index: if you place the stones on a printed text, for example, a page of a book, you will not be able to see the letters through the original.
• Defects and inclusions. They are present in real stones and are absent in fakes, but in no case are they cracks on the surface, scratches or chips.
• Light scattering and ultraviolet. A beam of light directed through a fake will remain just as intense. A real diamond glows under ultraviolet light.
• Marker drawing. A line drawn with a felt-tip pen or marker on the surface of a gemstone will be clear and even, whereas on a fake it will be blurry.
• Exposure to acids. Submerged in an acidic solution, a real diamond will endure the test with dignity, emerging unharmed.
• Indelible. It is difficult to erase a real stone, so you will have to examine the edges of the stone that has raised doubts. If they are smoothed out and appear erased, it is a fake.

Diamond rightly deserves the title of a unique and irreplaceable stone in the industry. At different times it was used for various purposes, but only when it gained jewelry interest did it become truly expensive. Its cost depends on the processing method, shape and changeability of fashion, but demand always remains high and is unlikely to ever change.

Diamonds with rare and beautiful colors are especially highly valued. Thus, Paul I bought a red-pink diamond weighing 10 carats for 100,000 rubles. The deep blue Indian Goppe diamond, weighing 44.5 carats, is one of the most valuable diamonds in the world.

Thanks to scientific and technological progress in the second half of the 20th century, it became possible to change the color of natural diamonds. By bombarding diamond crystals with electrons, protons, neutrons and subsequent heat treatment, it is possible to color them yellow, blue, green, brown and smoky. Diamonds irradiated in a nuclear reactor become green and brown, while diamonds placed in a particle accelerator become blue or cyan. Depending on the nature and intensity of irradiation, a color change can occur only in the surface layer or throughout the entire volume of the crystal; it can disappear after a short time, it can disappear after a short time, or remain unchanged for years.

Naturally occurring crystals rarely have the shape of regular polyhedra. Usually their edges are unevenly developed, have cracks, streaks, growths, and often have foreign inclusions. Therefore, in natural crystals there is usually no play of light, and before the invention of the method of cutting and polishing diamonds, they did not have the price that they subsequently acquired. In ancient times, transparent octahedral diamond crystals with mirror-smooth edges were most valued. According to legend, the robe of Saint Louis was decorated with such diamonds.

Even in ancient India, it was noticed that when one diamond rubs against another face, they are polished and their brilliance increases. After some time, in India, and later in Italy, France and Belgium, diamond cutting with a “platform” or “octahedron” began to be used. For such a simple cut, natural octagonal crystals were taken or blocks of the appropriate shape were cleaved from diamond crystals of a different shape. Cutting consisted of grinding down the opposite tips of the octahedron until, instead of one of them, a new wide flat face, called a “platform,” was formed, and in place of the second, a small blunt face, known as “culets.”

Subsequently, people tried to process the diamond so that as many rays of light falling on its faces as possible would undergo surface and internal reflection. For this stone it was necessary to give the shape of a polyhedron with a certain mutual orientation of the faces.

It is believed that Ludwig Berkem was the first European to learn how to polish diamonds. He noticed that when one diamond rubbed against another, they polished. In 1454, he cut his first diamond, which was later called “Sancy”. After Berkem's death, the secret of diamond polishing was lost, but was soon found again.

The real beauty, brilliance and enchanting “play” of light rays in diamonds is revealed and achieved as a result of special mechanical processing of natural transparent crystals, which are then called diamonds. Large diamonds are called solitaires. Processing involves splitting or sawing, then turning and cutting the crystals on all sides to give them a special shape.

Diamond splitting makes it possible, with minor losses of raw materials and low labor costs, to separate crystals into parts for more efficient use, in particular, to get rid of areas of the crystal with defects and foreign inclusions. This operation requires great skill, since even with one careless blow the diamond can be turned into fragments unsuitable for making diamonds.

Sawing is necessary to separate natural crystals into pieces when processing them into diamonds. It was used already in the 17th century. In those days, iron wire coated with diamond powder was used to cut diamonds. The process of sawing large crystals lasted for many months and a large amount of diamond chips was consumed. Sawing the Regent diamond, which weighed 410 carats, took about two years. Later, apparently in the middle of the 19th century, diamond saws appeared, which were not significantly different from modern ones. As I.I. Shafranovsky says in his book “Diamonds,” they are a thin (0.1-0.5 mm) rapidly rotating metal disk onto which a suspension of fine diamond powder is fed. In the 20th century, installations for cutting diamonds with ultrasound, for electroerosive, laser and electronic cutting of crystals appeared.

Diamond turning is one of the most natural operations in the technological cycle of diamond production. The degree of use of raw materials and the quality of finished stones largely depend on it. The purpose of turning is to give the workpiece the shape of the future diamond, prepare it for cutting and remove all or at least some of the defects.

Until the beginning of the 20th century, diamonds were cut by hand. Here is how Epifanov V.I. describes this process in his book “Technology of Processing Diamonds into Diamonds”: “...Two diamonds were fixed in special mandrels, and turning was carried out by rubbing them against each other. For many weeks and months, a man with great effort sharpened the blank for the future diamond. However, in this way, even with the high skill and hard work of the worker, it was extremely difficult to ensure the correct geometric shape of the workpiece.”

At the beginning of the 20th century, a machine for turning diamonds was invented, as a result of which the quality of processing sharply improved and labor productivity increased. The working parts of the first machines were driven into rotation using foot pedals, and later from an electric motor. In the second half of the 20th century, the appearance of machine tools also underwent significant changes.

Cutting is the final process of processing diamonds in order to give them an aesthetic shape, achieve the characteristic shine and “play of light” of this mineral, as well as to eliminate cracks, gouges and other surface or near-surface defects. Grinding involves giving the surface of the workpiece regularly spaced edges of a certain shape; polishing ensures a mirror-smooth surface on the edges obtained during grinding. Cutting is rightfully considered the most complex and responsible process in the production of diamonds. To successfully implement it, in addition to knowledge and experience, artistic taste is also required. Cutting is done using a rapidly rotating cast iron disk, into the surface of which diamond powder diluted in burdock or olive oil is rubbed. In this case, the shape of the resulting polyhedron as a whole and the relative position of the faces are made in such a way that most of the supplied light penetrates inside, but does not pass through, but returns back.

Diamond not only refracts and reflects light rays very strongly, but also has another very important optical property that determines the exceptional beauty of this stone. So, if for red light the refractive index is 2.402, then for violet rays it reaches 2.465. The difference in the refractive indices of violet and red rays (dispersion) in diamond is 5 times greater than that of rock crystal, and 2 times higher than the corresponding characteristic of the best honeycomb glasses. Due to their high dispersion, diamonds have a highly pronounced property of decomposing the white color into its constituent rainbow colors. For this reason, the same stone appears to have different colors depending on the position of the light source and the observer.

High light refraction and dispersion create a unique “game” of diamonds, expressed in an enchanting combination of the brilliance of the upper edges with bright flashes of light and continuous shimmering of all the colors of the rainbow inside the stone during its slow rotation.

Diamond cutting is a complex and very labor-intensive process. Processing large stones takes months, while unique ones take several years. The resulting diamonds are about 1/2, and sometimes only 1/3, of the original mass of a rough diamond. The final cost of the stone doubles or triples. Before cutting large diamonds, special calculations are performed to determine the shape of the future diamond that will provide the best “play” and allow maximum preservation of the mass of the original crystal. As a result, diamonds are not always isometric and can have an elongated or even teardrop shape.

Diamonds differ in the overall shape of the stone and the nature of the cut, expressed in the variability in the number, shape and location of the faces.

According to the shape in plan, the following main types are usually distinguished among diamonds: round, fancy (“marquise”, “pear” and “oval”), rectangular (“baguette”) and rectangular with cut corners (“emerald”). The shape of round and fancy diamonds is set during roughening (grinding), while other shapes are achieved during the cutting process.

According to the nature of the diamond cut, there are three main types: the actual diamond cut, the step cut and the rose cut. In diamond-cut stones, the edges of the different tiers are staggered relative to each other. The outlines of the faces correspond to a rhombus or triangle. The area at the upper end of the stone has the shape of a regular polygon. This type of cut is used mainly on round and fancy shaped diamonds. A step cut differs from a diamond cut in that the edges of adjacent tiers are located one above the other, and their outlines correspond to trapezoids or isosceles triangles. The area on the upper surface of the stone has the shape of a polygon with sharp or cut corners. This type of cut is typical for rectangular diamonds.

Small and sometimes large diamonds are often cut in the shape of a “rose” or “rosette”. With this type of cut, the stone has a flat base, and its upper part is convex and consists of 6, 8, 12, 24 or 32 faces converging at one vertex (Fig. 1).

Picture 1.

The shape of such diamonds somewhat resembles a rosebud, which explains the name of this type of cut. Stones with 12 or fewer facets are called “Anver roses,” and those with a larger number of facets are called “crowned roses.” Sometimes a double rose cut is used, in which the upper and lower parts of the stone are faceted with a rose. With “rosettes,” the play of light is much weaker than brilliant cut stones, and therefore, given the same size, color and clarity, rose cut diamonds usually account for about 20% of the value of brilliant cut diamonds.

The rose cut appeared in the mid-17th century, and the diamond cut began to be used at the end of the same century. The latter was continuously improved until the development of the “ideal” cut in the first half of the 20th century, and in the second half of the new “Highlight Cut” and “impariant” cuts.

The brilliant cut makes maximum use of the optical properties of the diamond, providing the utmost play of light and brilliance, thereby best revealing the natural beauty of the mineral.

For defective and colored diamonds, in order to make fuller use of the raw material, deviations from the geometric parameters of the ideal cut and the use of the so-called practical brilliant cut of several types are allowed. The play of such diamonds is reduced either due to light loss or due to a decrease in the dispersion effect.

The play of diamonds largely depends not only on geometry, but also on the number and size of facets. Large diamonds have more facets than small ones. The usual dimensions of the edges are from 0.5 to 3 mm, depending on the size of the stone. Diamonds weighing up to 0.03 carats usually have a simple cut - 17 facets. For good diamonds weighing 0.03-0.05 carats, a Swiss cut of 33 facets is used. A full cut of 57 facets is used for diamonds weighing more than 0.05 carats.

In the 60s of our century, the Belgian lapidary M. Westreich created a new form of cutting diamonds into 73 facets, called the “Highlight Cut”. This cut significantly improves the “play” of the stone with a slight increase in raw material consumption and is recommended for diamonds weighing more than 1 carat.

For large diamonds, the 86-facet royal cut and the 102-facet majestic cut are used.

The love for their work and the deep faith of diamond cutters in the presence of the yet undiscovered beauty of the stone encourage them to new searches. As we can learn from I. A. Efremov’s book “Tales of the Extraordinary,” the engineer Maximo-Elbe re-calculated the optics of diamonds and developed a new method for cutting an “unpaired” “imparant” diamond. The name comes from the features of the new type of cut. If a conventional cut is based on the symmetries of an octahedron, then with the new cutting method, the diamond platform looks like a 9-, 11-, 13- or 15-sided diamond. The most effective are 11-sided ones.

The odd cut has two advantages over the regular diamond cut. Firstly, each light ray falling inside the stone is reflected and comes out back through two inclined faces, and secondly, the light rays emerging from the crystal form a spectrum that is wider and more acceptable to the eye, making such a diamond seem much more beautiful than an ordinary one. cut.

In terms of brilliance, “impariant” is 25-30% superior to diamonds with an even number of facets. Increased brilliance and “play” visually improve the color of the stone, and therefore the yellow “imparant” appears whiter than the same stone processed in the usual way. However, while a symmetrical diamond can be cut by hand, an “imparant” cannot be obtained without special equipment.

A special type includes step-cut diamonds. The ideal geometry parameters for them have not been calculated, but special conditions have been established to ensure maximum “play” of light and the color effect of the stones. Among step-cut diamonds, there are several varieties: baguette, trapezoidal baguette, emerald, etc. All diamonds of this type are characterized by a girdle shape - a rectangle with sharp or cut corners. The height of the tiers decreases in the direction from the girdle to the culet and from the girdle to the platform. The width of the platform is 60-70% of the width of the diamond.

In the early 60s, reports appeared about the creation of a fundamentally new form of diamond cutting, called “princess”. Its development took 13 years, a special tool was made and the methods of diamond processing were changed in all main operations - sawing, turning and cutting.

Princess diamonds are slab-shaped with regularly alternating grooves on the bottom surface. Each plate has the shape of a square, rectangle, polygon, etc. The top of the plate is ground in the form of a tabular area with a small number of edges, and it is cut with a series of Y-shaped grooves, the “walls” of which are inclined at an angle of 41° to the plane being dissected. Thanks to this, complete internal reflection of light is achieved.

The “Princess” diamond, which has the shape of a heart, received the highest rating. From above it has the appearance of perfectly polished two semicircles touching at one point, and tangents to them converging at an angle of 90° (Fig. 2).

Figure 2.

Grooves are applied on the bottom surface at a distance of 0.9 mm from each other. When set in jewelry, princess-cut diamonds are arranged in a variety of patterns (Fig. 3).

From one octahedral diamond crystal, sawing can produce two round diamonds or four princess-shaped diamonds, and with much less loss of raw materials. The new cutting method makes it possible to standardize the production of stones of any shape and size, rationally use raw diamonds of various shapes, and also successfully produce diamonds from a significant part of “waste” in the shape of triangular plates, which are obtained by chipping large crystals during primary processing.