4. Titanium Alloys Titanium is a silver-white metal. It is one of the most common elements in nature. Among other elements in terms of prevalence in the earth's crust (0.61%), it ranks tenth. Titanium is light (its density is 4.5 g / cm 3), refractory

Alloys of gold For the manufacture of jewelry and other products, pure metals are not always used. This happens due to the high cost of precious metals, their insufficient hardness and wear resistance, therefore, in practice, alloys are most often used,

7. Copper-based alloys Copper is an element of the first group of the periodic system, atomic mass- 63.54, serial number - 29, melting point - 1083 ° C, boiling point - 2360 ° C. It has a cubic face-centered lattice with a = 0.361 nm (3.61?). Density - 8.93 g / cm2.

7.1. Alloys of copper and nickel Copper and nickel are infinitely soluble in both liquid and solid state. The state diagram of Si – Ni is shown in fig. 7.1. The structure of all double copper-nickel alloys is a solid solution of these elements. Crystal cell -

10. Silver and its alloys Silver is a chemical element, a metal. Atomic number 47, atomic weight 107.8. Density 10.5 g/cm3. The crystal lattice is face-centered cubic (fcc). Melting point 963 °C, boiling point 2865 °C. Brinell hardness 16.7. Silver - white metal

10.3. Silver alloys of various tests Silver alloy of the 950th test. Alloy SrM950 is used for enameling and blackening. The color of this alloy corresponds to the color of pure silver. The alloy lends itself very well to pressure treatment. It is also used for deep drawing, chasing,

11. Gold and its alloys Gold is a chemical element, a metal. Atomic number 79, atomic weight 196.97, density 19.32 g/cm3. The crystal lattice is face-centered cubic (fcc). Melting point 1063 °C, boiling point 2970 °C. Brinell hardness - 18.5. Gold - yellow metal

11.3. Gold alloys of various tests Alloy of the 750th test. As mentioned earlier, gold and copper have unlimited mutual solubility, but at 50 atomic % and 25 atomic % gold, the AgCu and AgCu type ordering occurs in these alloys. Single-Phase Solid Solutions on Cooling

11.6. Gold alloys for solders In the manufacture of jewelry and art products from gold alloys, soldering is used. The composition and temperature range of melting jewelry solders for soldering gold alloys are given in Table. 11.9. Marking of gold solders is carried out as follows

45. Copper; influence of impurities on the properties of copper. Brass, bronze, copper-nickel alloys Copper is a red metal, in a fracture color pink, has a melting point of 1083 ° C. The crystal lattice of the FCC with a period of 0.31607 pits. The density of copper is 8.94 g/cm3. Copper has high

46. ​​Magnesium and its alloys Magnesium is a reactive metal: the MdO oxide film formed in air, due to its higher density than that of magnesium itself, cracks and has no protective properties; magnesium powder and shavings are highly flammable; hot and

47. Titanium and its alloys Titanium and alloys based on it have high corrosion resistance and specific strength. Disadvantages of titanium: its active interaction with atmospheric gases, a tendency to hydrogen embrittlement. Nitrogen, carbon, oxygen and hydrogen, strengthening titanium,

At present, it is difficult to surprise anyone with a fake product. Absolutely everything is forged - from food to money, jewelry and works of art. And it is fake jewelry that costs customers the most. According to average statistics, in Russian jewelry stores imitation of the old precious metal- gold - already reaches half of total number presented products. And imitation of an old piece of gold will definitely cost more than fake newfangled jewelry. How to buy a real product made of old gold, and not a cheap alloy that looks like a noble metal?

To understand how to distinguish a material that looks like gold from a real precious metal, you need to know which alloys can imitate appearance old gold. If you are unlucky, you can buy one of the following alloys:

1. Aluminum bronze. It is an alloy of a golden yellow hue. Perfectly imitates gold. Approximately 90% of this alloy is copper, the rest is aluminum.
2. Batbronze. It also has a beautiful golden yellow color. Usually used for the manufacture of various art products. Unscrupulous sellers can pass it off to gullible buyers as precious metal.
3. Batmetal. In some countries, tableware is made from it. This alloy imitates gold quite well.
4. Belgica. This alloy is more similar to platinum. Includes iron, nickel and chromium. There is no hint of precious metal.
5. Vermeil is fire-worked silver. In the process of processing, the metal becomes similar to gold. But paying as much for silver as gold is not the best option.
6. Hameltonmetal is an alloy of zinc and copper. It has a beautiful golden yellow color. It is used for gilding various products.
7. Goldin. It is an alloy of aluminum and copper. In some countries, budget jewelry is made from it. Although the metal is beautiful, it has nothing in common with gold, except for its appearance.

1. Durametal. The composition of this alloy includes aluminum, copper and zinc. The ingredients are mixed in certain proportions and subjected to special processing. The final product has a beautiful golden-bronze hue. But again, it's not gold.
2. Gold leaf. These very thin sheets are used for gilding a variety of wood and metal products, as well as in other areas.
3. Musiv is a tin sulfide with an attractive golden sheen. It is usually used for gilding. Its only advantage is that the material does not blacken over time.
4. Mannheim Gold. It is an alloy of zinc, copper and tin. It has a "gold" finish.
5. Mosaic gold. This alloy is made up of zinc and copper. Has an original shade of native gold.
6. Overhead gold is an alloy of copper with a layer of precious metal.
7. Oride. This alloy consists of zinc, copper and tin. Sometimes iron is added. It is used for casting inexpensive jewelry.
8. Pinchback, which is an alloy of zinc and copper. Used for the production of budget jewelry. It is issued for gold by unscrupulous merchants.
9. Platinor is an alloy of silver, copper, nickel, zinc and platinum. The percentage of precious metals is so small that unscrupulous sellers win big by passing off such items as real gold.
10. Similor. This alloy contains zinc, copper and tin. Usually products are covered with gilding.
11. Tompac is one of the alloys most often passed off as gold. It contains zinc and copper. Has a beautiful shade. Thanks to copper, it is resistant to corrosion.
12. Electron. It contains silver and gold. In ancient times, the alloy was used to make coins.

The value of a jewelry sample

It is important to consider that even the presence of a sample is not at all a guarantee that you are buying a precious metal. If it is still a little clear to the buyer with Russian markings (usually these are numbers next to a female profile or a star and a hammer and sickle), then with samples according to foreign standards, everything is much more complicated.

And the knowledge that 14-carat gold corresponds to the “domestic” 585th sample, and a product made of 18-carat material can be regarded as 750th sample, practically does not help in business. Trials by trials, but no one is immune from buying a chain, in which, at best, half is made of precious metal, and the rest is made of various kinds of alloys.

It is very difficult to check for authenticity. Not every jewelry detector reacts. Going to the store to buy a gold item, take some jewelry made of the same material with you. Throw your product and the product you are looking at in the window and compare the sound it makes. If the sounds are similar, you most likely managed to find real gold.

Can also be applied psychological methods. Try to "pick" the surface of the item you are looking at a little so that the consultant can see it. You won’t do anything terrible to the product, but a lot can be understood from the seller’s reaction.

Jewelry quality assessment

Checking the quality of jewelry in Russia belongs to the powers of the State Assay Office. Theoretically, products with its breakdown are real gold. However, in practice, everything is much more complicated. The problem is that most of the jewelry is checked superficially. As a rule, only the layer of coating scraped off the surface of the jewelry is analyzed. Thus, the seal only testifies to the fact that upper layer jewelry actually made of gold. But what is under this layer is already a mystery.

A knowledgeable user may argue that precious items are cut, after which the cut is subjected to detailed chemical analysis. Yes, it does. But such a test passes only one product to choose from a whole batch of the same type of product. So if the tested sample is made of gold, and the rest of the products are made of incomprehensible alloys, the assay office is no longer responsible for this.

It is also important to consider that only about half of the products in the country are currently labeled accordingly. If we take into account the specifics of the activities of the aforementioned assay office, then we can come to such a disappointing conclusion that there are even fewer high-quality jewelry on sale.

And there is nothing surprising in this. Fake jewelry is very profitable. They are small in size and are sold at a high price, if calculated per unit volume. It is very convenient for smugglers to work with such products. Their production does not require large production facilities. And complex technological operations, as a rule, are also not required. So the shadow jewelry business is developing and prospering. Therefore, you need to carefully prepare for the purchase.

With other metals in various proportions.

For example: alloys that consist of 14 parts and 10 parts of another metal are 14 carat gold, 18 parts of gold and 6 parts of another metal, 18 carat, etc.

This ratio is most often expressed as a sample: 14/24 is equal to 585 samples and 18/24 is.

Red and rose gold

Rose gold is the result alloy of gold and copper, and is widely used for specialized jewelry. Pink steel jewelry became popular all over the world only at the beginning of the 20th century, and now only wedding rings are made from this alloy.

Red or pink is also called Russian, because back in the 18th century it was popular in Russia, and in the West they didn’t even know about it.

The main formulas for the composition of pink or red gold:

18K Red: 75% gold, 25% copper

18K Rose Gold: 75% Gold, 22.25% Copper, 2.75% Silver

18K Pink : 75% gold, 20% copper, 5% silver

Also, up to 15 percent zinc is often added - which adds a yellowish-red tint to the alloy.

In ancient times, impurities in the smelting process often turned gold to a reddish color. That is why in many Greco-Roman texts and even in many works of the Middle Ages, red is described.

green gold

Green is obtained by combining gold and silver. Pure green gold does not exist, only greenish-yellow.

The ratio of gold in this alloy is 75% gold and 25% silver (or 73% gold and 27% silver). Green gold was known as early as 860 BC under the name electrum - a natural alloy of gold and.

Also often added to the alloy - it is he who adds green tint alloy and betrays the effect of transparency. An alloy of 75 percent gold, 23 percent copper and 2 percent cadmium gives a light green tint, 75 percent gold, 15 percent silver, 6 percent copper and 4 percent cadmium gives a dark green tint. But it should be borne in mind that cadmium is a toxic metal and it is strictly forbidden to wear jewelry containing cadmium for a long time.

black gold

Black is obtained in four ways:

1.Coating alloy of rhodium and ruthenium,

2.Patination with sulfur and oxygen compounds.

3. Use of amorphous carbon during the manufacture

4. Controlled oxidation - most often bringing to oxidation in a ratio of 75 percent gold and 25 percent gold.

Blue gold represents alloy of gold and indium. It contains 46% gold (about 12 carats) and 54% indium.

It is worth noting the compounds that are passed off as gold, but in fact, there is practically no gold in them, or none at all, so you should pay special attention to this list.

– bright yellow alloy, containing 90 percent and 10 percent aluminum - most often passed off as gold, because it is a low-cost method, and is indistinguishable from the original to the naked eye.

In second place is an alloy called batbronze, which was developed in the middle of the 20th century as alloy for gilding and for the manufacture of industrial, stage parts.

An alloy to which is added, but already in in large numbers, is called Batmetal. It is mainly used in the production of tableware.

The French coined the term "vermeil", which is used to designate, covered with gold in small quantities. Vermeil is made only on fire.

Also worth noting is Hameltonmetal, which consists of 66.7 percent copper, 33.3 percent zinc. The alloy has a yellowish color, it is used to cover the gold color of industrial parts.

The Americans came up with the word "goldin" - alloy of copper and aluminum, is used for the manufacture of cheap, low-quality jewelry.

Durametal - alloy of zinc, aluminum and copper which has a golden yellowish hue.

The alloy, which contains 83.6 percent copper, 9.34 percent zinc and 7 percent, has a golden hue, and completely imitates gold and is called Mannheim.

66 percent copper and 34 percent zinc - the alloy is similar in color to native and is passed off as raw gold.

The French also coined the expression "oreide" - "French gold". "French gold" is used to make inexpensive ones.

An alloy consisting of copper and zinc is called tompak. Tombac was first used by the London watchmaker Christopher Pinchbecker in the early 19th century, it perfectly imitates gold because it is resistant to corrosion and has high strength.

An alloy containing 57 percent copper, 18 percent platinum, 10 percent silver, 9 percent and 6 percent zinc is platinor. Platinor has a beautiful golden color, but due to its high cost, it is very rarely used as a substitute for gold.

The alloy, which is used to make inexpensive jewelry, is called "gold alloy with", but in fact, it does not contain a single gram of gold, but at the same time it is a 100 percent copy of 585 gold.

Therefore, it is worthwhile to carefully check the jewelry before buying, and after the purchase, it is worth contacting an independent and fully checking the product for authenticity.

Although gold is mined in our time in large quantities, but in the jewelry industry, quite often, quite legally, alloys of different metals are often used, which cannot be distinguished from gold with the naked eye. However, this led to the emergence of fake gold, which is often used by scammers and dishonest businessmen.

Secrets of transmutation.

Throughout the ages, scientists, not only chemists, but also physicists, as well as medieval alchemists, have struggled with the question, is it even possible to obtain another metal similar to gold in a scientific way? Nuclear scientists have proved that at the atomic level, one metal can acquire the properties of another by transmuting chemical elements that are nearby in the periodic table (for example, mercury and platinum can turn into stable gold as a result of the reaction).

By the way, this is one of the very first and reliable ways to get gold from metal. Even in the Middle Ages, alchemists cheated in this way before kings and emperors. Gold powder was dissolved in mercury, then the mercury was evaporated and a gold ingot remained.

All other ways to get gold by manipulating different metals (iron, tin, lead) can only lead to an alloy with a small admixture of gold. Most often, this is exactly what scammers achieve, whose main task is to make a fake as high quality as possible.

Some scientist even jokingly summed up the "scientific" base under the similarity of bronze to gold. He said that if you add up the charges of the nuclei of the alloy components (29 for copper and 50 for tin), you will certainly get "gold".

However, in order not to get into trouble when buying real gold jewelry, it is advisable to know which alloys form a metal similar to gold. Although even experts cannot always distinguish a fake, especially if gold is really added to the alloy. In this case, they say that this is gold of a very low standard. .

Not all that glitters is gold.

So, to obtain metals with a golden sheen, alloys of copper, zinc, tin, sometimes aluminum, and silver are most often used.

The closest thing to the original is an alloy called "Nuremberg Gold", where gold and silver are combined in the composition in a ratio of 50x50.

The alloys obtained from copper, zinc and tin, taken in various proportions, include "Mannheim gold", "Talmi gold" (84.4%: 12.2%: 1.7%), which is distinguished by its extraordinary resistance to corrosion; "similor" (83.7:9.3:7); "oride" (80:15:5). All of them have a golden sheen identical to natural.

"American gold" is cast from copper (100 g) to which are added: ammonia (3.6 g), lime (1.8 g), cream of tartar (9 g) and magnesia (6 g). To obtain "French Gold" this mixture is melted for an hour, adding additional grained zinc (17 g). These alloys can be distinguished from gold only by their specific gravity.

Tompak and pinchback (English gold) are made from copper and zinc alloys, the ratio of parts of copper and zinc is almost the same (9:1 or 8.3:1.7). Both alloys have a very beautiful golden color, are resistant to corrosion and are used for making costume jewelry, icon frames, and other decorations. This group also includes mosaic gold (66:34), which is more similar in color to native gold.

From copper and aluminum (90:10) get aluminum bronze - "aufor". Beryllium bronze is called "randol" (popular in prisons, where it goes on dental crowns).

With the use of iron, zinc and copper, they make "Aich's Alloy" (1.8g: 38g: 60g). Also popular is the production of gold leaf and Hamilton metal, which are used for gilding. And brass is called prince metal.

Dreams of the gold of Croesus.

In addition to alloys of various metals, obtained by man-made method, which imitate the color of gold, there are minerals in nature that captivate the eye with their brilliance from a distance. For their bright golden highlights, people called mica crystals "cat's gold", and pieces of pyrite can be confused with gold nuggets because of its muted brass luster. Aventurine sparkles with golden sand. In all likelihood, most of the untold riches of King Croesus, about which legends were composed, consisted of pyrite crystals.

Do not give rest old recipes alchemists and today's scientists. So, at the end of the last century, Canadian chemists managed to get gold-colored crystals from ... mercury (mercury arsenofluoride)!

And the ancient alchemists sometimes performed such "miracles" that they could not unravel for several millennia. For example, the secret of the medallion, which the monk Wenzel Seiler in 1667, in full view of the imperial family, turned from silver into gold and presented to Emperor Leopold I.

The secret of the medallion

For 250 years, the best Viennese chemists struggled to unravel this mystery. From the medal, which is still kept in the Museum of the History of Art, scrapings were repeatedly taken. But they all showed the presence of gold, and the color was quite appropriate. Moreover, part of the medal, which the monk held with his fingers, remained silver.

The last experiment that put an end to this story was carried out in the last century. Through microanalysis, it was found that the medallion was made of an alloy of silver with gold and copper (43:48:7), with a small addition of iron, tin and zinc. And the color of the metal changed as a result of the reaction with a 50% solution of nitric acid. Today, this process is actively used by modern jewelers under the name "yellow boiling".

As you know, pure gold has a number of outstanding physical and chemical properties, but it does not differ in strength and wear resistance. Since ancient times, people have been solving this problem by adding other metals (ligatures) to gold alloys.

A strictly defined alloy content in the alloy significantly improves the quality of the noble metal and increases its service life without compromising its original solar brilliance and radiance.
What metals are added as an alloy to gold, and how do the properties of the most noble metal in the alloy change in this case?

Gold + Silver

When silver is added, the alloy becomes softer and more malleable, and the melting point decreases. A small amount of silver turns the color of the alloy yellow-green, as the proportion of silver increases, the color of the alloy turns pale and acquires a pale lemon color. If the alloy contains 65% silver, it will turn white.

Gold + Copper

Copper added to the alloy, while maintaining the malleability and malleability of the alloy, increases its hardness. At the same time, the color of the alloy acquires a reddish tint that is familiar to us, thanks to domestic decorations, an increase in the proportion of copper in the alloy only enhances the red tint. There is one significant disadvantage of copper ligature - it reduces the resistance of the alloy to corrosion, so it is used in tandem with silver.

Gold + Palladium

The addition of palladium increases the melting point of gold, while ductility and malleability do not change. Palladium, like silver, causes the alloy to turn pale, only at a much lower percentage - 10% palladium is already added to the alloy White color. Rarely used for making jewelry, because. is a refractory alloy.

Gold + Nickel

Nickel ligature increases the malleability, malleability of the alloy and significantly increases its hardness. The alloy thus acquires a pale yellow color.

Gold + Platinum

Platinum increases the melting point of the alloy, increasing its elasticity. The combination in an alloy of gold with platinum successfully prevents the corrosion process. The addition of platinum to an alloy of gold gives it a whitish hue, the characteristic yellowness of gold disappears already at a content of 8.4% platinum in the alloy.

Gold + Cadmium

Cadmium as an alloying additive retains the malleability and ductility of the alloy, but at the same time significantly reduces its melting point. The color of an alloy of gold with cadmium varies from yellow to gray, it all depends on the percentage of cadmium in the alloy. The resulting alloy is usually used as a solder. In general, such an alloy is rarely used in the jewelry industry, since it is a very fragile material.

Gold + Zinc

Zinc reduces the melting point of the alloy, increases its fluidity, introduces a noticeable brittleness to the alloy and a greenish tint.

On the territory of Russia, the amount of gold in gold alloys is controlled by the state, and, in accordance with the decree of the Government Russian Federation dated June 18, 1999 No. 643 "On the procedure for testing and branding products made of precious metals", the following samples of gold jewelry alloys are possible: 375, 500, 585, 750, 958, 999. Others are not possible, so be careful - scammers in this area more than enough.

Alloys imitating gold

Today, in addition to the "legitimate" gold alloys, there are many imitation alloys, because the fake of the noble metal is very profitable business, so the purchase of jewelry should be supported not only by what

Modern underground jewelers have achieved such mastery in the manufacture of fake jewelry that only a specialist can distinguish fakes from real gold.

So the following alloys are often given out for the precious yellow metal:

• aluminum bronze (other names - aufir, aural, aufor) - a golden yellow alloy. For 90 parts of copper, there are 10 parts of aluminum;
• bathbronze (bathbronze) - an alloy of bronze and tin, mainly used as gilding and for casting artistic and industrial products;
• bathmetal (bathmetall) - an alloy in which a zinc ligature is added (used in England for the production of tableware;
• Vermeil is a French term for silver gilded on fire;
• hamiltonmetal (hamiltonmetell) - an alloy of 66.7 parts of copper and 33.3 parts of zinc of golden yellow color, often used for gilding in artistic and industrial products;
• goldin (goldin) - an alloy of copper and aluminum. In Germany goes to the manufacture of cheap jewelry;
• durametal (durametall) - an alloy of copper, zinc and aluminum of a golden-bronze color;
• Mannheim gold - an alloy consisting of 83.6 parts of copper, 9.4 parts of zinc and 7 parts of tin and having the color of gold;
• mosaic gold - an alloy of 66 copper and 34 zinc, reminiscent of native gold in color;
• oride (oreide), "French gold" - a gold-colored alloy, which includes 80 parts of copper, 15 parts of zinc and 5 parts of tin, is used for casting inexpensive jewelry;
• tompak (similor, pinchback) - "English gold", an alloy of copper and zinc (the overwhelming mass in the alloy is copper - 83-93%), invented by the London watchmaker Christopher Pinchbecker. It has high plasticity and corrosion resistance. It is used to create inexpensive jewelry, costume jewelry, gilding and enameling;
• platinor - an alloy, which includes 57% copper, 18% platinum, 10% silver, 9% nickel and 6% zinc; has a beautiful golden color;
• “an alloy of gold with titanium” - this alloy does not include even a gram of gold, but the alloy itself resembles 585 gold in color. Used to make inexpensive jewelry.

Almost everyone can become the owner of low-quality jewelry - fake gold is sold not only by dubious shops in Turkey, Italy, Israel, China, but also by some domestic jewelry stores.

The choice of jewelry made of gold (and other precious metal) should be taken seriously, knowing the basic axioms and rules, only then you can minimize the risk of acquiring fake gold. In order to have an idea of ​​how to distinguish real gold from a fake, you should familiarize yourself with the material previously published on the site.