Yellow patina on copper coins. Patination of copper coins

About 2600 and a half years ago the first coins began to appear. Their material, variety and value have changed dramatically since those times. Today, any rare coin gives the impression of something unique, and among them there are rare specimens.

For example, coins used in circulation on one island, which weighed up to five tons. These works of numismatics were made in the form of a plate. Such an amazing form of coins had a lot of advantages. The number of stones around the hut indicated how rich the island resident was, as well as a clear advantage - the weight of the coin, because it was not possible to carry it away.

In China, the role of monetary payments was assigned to metal plates weighing up to 4 kg. The number of coins on them reached hundreds. It was not difficult to count, but it was impossible to lose a coin. Two parts made up the Australian dollar: the part that was in the center was removed. Each part of the dollar had its own denomination.

Interesting
Not only ancient coins are the object of attention for collectors; investment and commemorative coins deservedly take their place among unique coins.

Due to their high price, many examples are a good economic investment. The greatest influence on the price of collectible pieces today is exerted by the technology of production itself, style, aesthetic value and circulation of the units produced.

Coins are made from a variety of metals and take a variety of shapes. Their weight can reach several kilograms, and the color scheme knows no bounds.

Royal coins

The tradition of producing coins with the image of the Tsar in Russia was introduced by Peter I. His profile was depicted on large coins. This law was repealed by Emperor Paul l. It is known that he was not distinguished by his attractive appearance. He introduced a ban on depicting his face on money, and this tradition was forgotten for almost a hundred years.

Alexander lll became emperor in 1881, issuing coins with the head of state again became a hot topic. But his face was allowed to be depicted only on money with a large denomination. Because significant money was not allowed to fall into the hands of the poor.

Nicholas II completely renewed this tradition during his reign. The Coronation Ruble was issued in 1896. This coin was passed down as a relic for entire generations. The cost of these numismatic products is about 24 thousand rubles, and if the product is in good condition, then the price reaches 114 thousand rubles.

The 1898 ruble is known for the fact that the relic is made of silver. The issue of the coin was dedicated to the opening of the monument to Alexander II. The price is 228 thousand rubles, but the cost of certain copies reaches 685 thousand rubles.

Commemorative ruble of 1912 - the price of such a coin is up to 85 thousand rubles.

The Gangut ruble is the last numismatic relic from the times of Tsarist Russia. The price of copies reaches 300 thousand rubles. If the coin is real, then its value can be about 2 million rubles or more.

A rare example of gold coins is 10 rubles from 1906. The number of coins that have survived to this day is only 10 units, which is why the price is very high - about 1.4 million rubles.

USSR coins

Of particular value among the coins of the USSR are the coins of 5 kopecks, 10 kopecks and 15 and 20 kopecks from 1931, 1934 and 1958. The price of many copies reaches 100 thousand rubles. In the market, the price of these products tends to rise rapidly. That is why these unique monetary calculations from the times of the USSR are a good way to invest.

The “St. George the Victorious” coin is the first USSR coin used for investment. The first circulation was 751 thousand copies. Unfortunately, this numismatic unit failed on the Western market.

Patina on coins

Patina is a film or coating on copper that forms on its alloys. It is a multilayer structure, but, as a rule, the top layer of green copper carbonate is considered patina. There are two types of patina: artificial and natural.

Interesting
The appearance of a natural patina usually takes several months; the wait is quite long. Then it is customary to use artificial patina.

Patination of copper coins

1. For this method you need to use 5 grams of manganese and 20 grams of copper sulfate. Dissolve two elements in 1 liter of water. Then this solution is brought to a temperature of 90 degrees. When the solution is heated sufficiently, place coins in it. There is no specific allotted holding time for coins.

2. The second method is carried out using a substance such as sulfur ointment. It should be applied to coins and left for 5 minutes. It is better to smear the coin under water, as the reaction occurs almost instantly. When the brown color becomes noticeable, the coin needs to be cleaned and rinsed well with water. This is done to prevent the coin from turning black. However, one should not exclude the possibility that it will turn black. To restore the brown tint to a coin, wipe it with a piece of cloth soaked in a fat-based liquid.

3. The third method is characterized by the use of sodium hyposulfite. A prerequisite is that the surface of the coin is dry. It is necessary that it stay in a heated sodium hyposulfite solution. After the coin has dried, you need to wipe it with a soft cloth. Thanks to this, the coin becomes bronze in color, and it is not afraid of corrosion.

Patination of silver coins

Patination of silver coins involves the presence of ammonia and ammonia. Place the coin in the freezer for half an hour. We bring the coin to a container with ammonia or ammonia. The coin will begin to acquire a gray patina instantly.

As previously described, the patination of coins depends on the material from which they are made, so you should carefully study and then choose the method of artificial aging of the coin that is most suitable for your coin.

Preservation of coins is no different from conservation of any objects made of copper and its alloys. Although such finds belong to “mass archaeological material,” this does not give reason to treat them haphazardly.

What is hidden under the word “conservation”? Conservation measures ensure the preservation of the material presence of the monument and prevent further losses of the original. Conservation is aimed only at preserving the pure substance, without paying attention to aesthetic improvements. Many people believe that preserving coins is just a matter of coating. This is far from true. Conservation includes various conservation work carried out directly at the site. For example, clearing and securing the original surface, as well as preventive conservation measures. For example, optimization of climatic conditions, proper packaging, presentation and storage.

Before talking about conservation measures, I would like to once again remind you of such a concept as the original surface. There is no such term in numismatics and general practice, but there is a concept - patina. Unfortunately, this is too general a definition of an oxide film, which often does not give any idea about the condition of the coin, and therefore the choice of the correct conservation methods. Although it is customary to divide patina into “noble” and “not noble,” it is often this statement that leads to the fact that the preserved original surface and its details are removed, guided by outdated aesthetic concepts.

What is the original surface? The original metal surface of the coin is replaced by metal salts during the corrosion process. Because this transformation occurs very slowly, such a layer conveys the nuances of the original surface. But, unfortunately, corrosion products and soil particles often cover relief details and distort the shape. The original surface not only bears the relief, but also gives us a good guide when cleaning the coin. This is a kind of boundary beyond which we cannot step (except in rare cases). Everything that is above the original surface can be called contamination, everything that is below is the original.

The picture shows a section of a coin taken using an electron microscope. The boundary between the original surface and deposits (contaminants) on the surface is clearly visible. Under the original surface there is a layer consisting of corrosion products.

Often, quite a lot of time passes before a coin reaches the restorer’s table. During this period, poorly preserved coins may suffer significant irreversible damage. There are several factors primarily involved, one of which is improper handling of the unstable patina.

In general terms, the following can be said on this topic:

1. After removing a coin from the soil, do not rub or try to clean the find in order to see it better. The find must be handled with extreme caution.

2. Try to immediately determine the condition of the patina and if damage is detected (porous structure, cracks and chips, bumps and growths, missing surface fragments, etc.) in a dense layer of patina, be sure to wrap the object in a damp cloth moistened with distilled water (or simply a damp cloth). ground) and place in a tightly closed box. This way we prevent the patina from drying out. In addition, the risk of physical damage to the patina caused by vibration and shock is minimized.

3. Try to reduce the period to a minimum between the extraction of the find and the start of desalting (rinsing). The find should not be kept in a damp cloth for a long time, otherwise there is a risk of subsequent corrosion. This especially applies to items that have active foci of bronze disease.

4. Perform preliminary cleaning (washing off the soil) only if the patina is stable.

5. For all finds that have a damaged patina (no matter whether it peels off or not), a salt washing process is required. But we must take into account that prolonged washing has a negative effect on the condition of the patina. Important: determine the optimal washing time. Typically, for finds with a thin layer of patina, this period does not exceed two days. If the patina condition allows, it is recommended to remove loose dirt with a soft brush and distilled water. If there is a possibility of the patina peeling off, then there can be no talk of any preliminary cleaning.

I would like to focus on rinsing with distilled water. The purpose of washing is not to soften oxides and soil residues, but to remove soluble salts located in the capillary system of the patina. Any plastic box with a tight-fitting lid will do for this. The lid not only prevents water evaporation, but also prevents the entry of gases and salts from the air. The container must be completely filled with water, otherwise there is a risk of harmful substances entering from the air gap. The coins should be as close to the surface of the water as possible. You can use a plastic strainer for this. During desalting, it is necessary to turn the coins over at least once, so the process of salt release from the bottom side of the coin goes much faster. This should be done not with your hands, but with tweezers. You can't put your fingers in the water.

:!: Important: the destructive ability of distilled water should not be underestimated. Distilled water is the best solvent for salts, including those that make up patina. Excessive exposure of coins to distilled water can cause irreversible damage. :!:

Exactly how long coins should be in the wash can only be determined experimentally, by measuring the concentration of salts with a salt meter or determining their quantity and quality in other ways. As a rule, the layer of impurities, including oxides, on the surface of the coin does not exceed a few millimeters. In this regard, the process of salt release occurs relatively quickly and takes from 24 hours to several days.

To improve the result, after the rinsing period has expired, you need to remove the coin with tweezers and wrap it in a wet napkin moistened with distilled water (clean, without added perfumes or oils). Lightly press the soaked cellulose onto the coin with a brush so that it is in full contact with the surface. You can also use toilet paper, but not chlorine-bleached one. After this, you need to place the cellulose-wrapped coins on a wire rack in a dry place. You must wait until the surface of the compress is completely dry and only then carefully remove it. When drying, migration of salts from the capillary system into the compress material occurs.

Salt washing is mandatory for all coins, except those that have a dense, undamaged patina.

Finds that have a noble patina can simply be rinsed with distilled water.

Determining the safety of coins

Ideally, the metal surface of the coin, or the entire coin, is converted to mineral through the process of corrosion without changing the shape of the object. There is only a replacement of one material by another. Thus, the surface of a copper coin is replaced by a new one, for example, a malachite surface. The formation of such a patina can be called pseudomorphosis. The appearance of a noble patina directly depends on the environment.

Depending on the mineral formed, the color of the surface of the coin can vary greatly.

Here are some examples of such patina:

Patina, which has an even, uniform color, is most preferred by collectors. But not all coins have such an original surface. In many cases, the process of converting a metal into a particular mineral does not occur uniformly. Due to this, the coin acquires a non-uniform shade. At first glance, such a patina does not look very aesthetically pleasing, but it is precisely it that is the source of information, namely the carrier of the relief.

Pollution and loss

If we talk about the condition of the coin, we can distinguish two main sub-points. Namely, contamination hiding the relief (original surface) and losses. As already mentioned, everything that is on top of the original surface can be classified as contamination. But not infrequently, the pollution itself is the source of information. For example, in corrosion products deposited on the surface, one can find remains of organic materials, be it old vegetation or the remains of a wallet. In addition, contamination can tell us about the conditions in which the coin was in the ground, how polluted the atmosphere was at one time or another, what fertilizers were used in this area, or where this coin was found in general, as well as provide answers to many other questions. questions.

Speaking of pollution, two types should be noted here: layers formed during the corrosion process and soil layers. As a rule, both types of pollution are present simultaneously.

Here are some examples:

In some cases, contamination covers the entire surface of the coin with a thick crust, making it completely impossible to determine the denomination, read the inscriptions or date. But still, under the layers of corrosion products and soil deposits there is always an original surface bearing numerous relief details.

The photographs below clearly show that under the layer of dirt you can find the original surface. The only question is how to properly clear such a surface and reveal all the preserved details, but we will return to this later.

Destruction and loss

Irreversible damage that is practically impossible to restore includes the loss of the original surface. In this case, there is a loss of part or all of the relief of the coin. Destruction of the patina can occur as a result of mechanical damage, chemical exposure, as a result of changes in external conditions, temperature changes, humidity (when the processes of recrystallization of copper salts in the corrosion layer can begin) or the washing out of unformed layers with water. This also includes destruction caused by improper handling of unstable patina.

Several examples of coins whose relief was almost completely lost

Ten pfennig 1912. The original surface has been preserved in fragments. Under the dark patina layer is a bright red loose layer of cuprite. The thickness of this layer is relatively large.

General view of the coin.

Reverse side of the coin. Loss.

Often, after cleaning, the coin looks very bad, I would even say not really bad. This is mainly due to the fact that the so-called patina was destroyed and the coin remained in a “negligee”. Selling such a coin is very problematic. It needs to be prepared a little for sale (like a car), i.e. apply patina.

In principle, patination of copper coins is not very difficult. The main difficulty is to ensure that the acquired color resembles the natural one as much as possible. There are many ways to patina copper coins, each with its own pros and cons. I only use three methods. I'll tell you a little about them.

Patination of copper coins using manganese and copper sulfate. Many numismatists consider this method the most “ideal”, since the color of the coin can be made from red to dark brown, and this induced patina will be very similar to the natural one. Patination occurs as follows - add 3-4 grams of manganese and about 10 grams of copper sulfate to water heated to 90 degrees (0.5 liters). Mix everything and place coins in this solution. As the solution cools, warm it up a little. Every 5 minutes, turn the coins over and check their color. Make sure the color turns bright brown. The big advantage of this patination is that the color is beautiful and relatively resistant to washing off.

Patination of copper coins using sulfur ointment. “Real” numismatists despise this method, which is quite simple. Take a coin and lightly spread sulfur ointment on it with your fingers. All this must be done in lukewarm water. Water is needed to make the coloring process slower. The final color of the coin will range from dark brown to matte black. The plus is that the worst coin can be revived a little, but the minus is that the color is unnatural and the patina is very easily washed off. In order to make the patina natural, after patination with sulfur ointment, the coin must be rubbed with a soft cloth dipped in oil. Sometimes you can achieve a very nice color.

I really like to patina copper coins naturally, i.e. sun and air. I conducted the following experiment - I placed the coins, cleaned to their very “nakedness,” on the roof of the house. Every two weeks I turned over the coins. The coins were burned by the sun and washed by rain for four months. The result was normal - the color changed from bright red to dull brown. If the coins had been left in the open air for at least 7-8 months, they would have become perfect. I highly recommend this method for those who are not in a hurry. The result will be amazing.

Hello, dear readers. In the next article we will tell you what patination of coins is and how to do it. Cleaning and patination of coins are almost always related to each other. Often, after the cleaning process, we get an unnatural shine of the coin or an unpleasant shade of color. “Now take half off the original price,” forum experts grumble, looking at your freshly cleaned copy. A coin patina tool or manual application of patina will help return the coin to its usual appearance. The methods for patination of coins depend on the metal with which we have to work.

Patination theory

The word “patina” seems to us to be natively Russian, like “old times” or “homeland,” but it came to us from the Italian language. It appears due to a chemical reaction that transforms the surface of the coin. On silver or copper, the patina looks beautiful, while the patina on an aluminum coin is a cloudy film, which is why such coins lose value. A patchy or partial patina also does not add charm to the coin. Therefore, the patina that disfigures the appearance of the coin is removed. It should be remembered that patina is part of a coin. If the oxidation processes affected the deep layers, then after cleaning, instead of a coin, we will get a thin plate with shapeless potholes instead of a pattern. But even well-preserved coins can look unsightly after cleaning. This is especially true for copper coins, which take on a striking red color. However, you can return the coin to the appearance of undisturbed antiquity. This is done by patination - the process of creating an artificial patina.

Availability of patina induction

To an unprepared collector, it seems that in order to achieve patina you need to be almost a medieval alchemist or work in a large chemical laboratory. This is wrong! Most patinas are achieved using simple methods using readily available ingredients. Despite the fact that patination of coins is the application of an additional layer that gives the surface of the coin a beautiful color, coin defects induced patina won't hide. Dark spots, potholes, nicks, smudges, etc. will remain in place, they will just change color. According to experienced collectors, artificial patina will not add anything to the price of the coin. But the patina induced by experienced hands is no different from natural, and the coin takes on a very attractive appearance in the eyes of potential buyers. The processes for inducing patina for different metals have fundamental differences. Simply put, there is no universal method. Let's look at some.

Patination of copper coins

There are many ways to apply patina to copper. A very popular method is using manganese and copper sulfate. If there is only a standard package (3 grams) of manganese, then take 10 grams of copper sulfate per half liter of water. If manganese is taken in an amount of five grams, copper sulfate will need 20 grams per liter. Heat the solution to 90 degrees. When the desired temperature is reached, place coins in the solution. The temperature should be controlled by warming the solution and periodically turning the coins over. The result: a wash-resistant bright brown patina. Pay attention to the toxicity of vitriol and take the precautions required when working with toxic substances.

A fixer (sodium hyposulfite) is used to create a patina on clean and grease-free coins. Soak the coins in the solution for 10 seconds to half a minute. Removed coins are wiped with a cloth. When the coin dries, the patination will give it a bronze color. The simplest way is to heat a coin in the flame of a gas stove burner, when the experimental specimen turns light brown. Copper plating is also an easy option, although less popular. Patination of coins with sulfur ointment is also not a complicated method. Work must be carried out in water. A coin rubbed with ointment receives a dark brown or grayish patina. To brighten, after a forty-minute pause, the coin is first polished with a napkin and then washed with a soapy brush. Experts do not recommend sulfur ointment, but it is quite suitable for experimenting with simple methods.

Patination of silver coins

It is recommended to patina silver with ammonia (an ordinary bottle of ammonia). The coin is placed in the freezer for half an hour. Fixing the experimental specimen by the edge with tweezers, we hold it for a minute to three over the open vial. As soon as the coin acquires the desired gray color. Then we rinse the coin in water and dry it. For those who don't want to bother with ammonia, a simple hard-boiled chicken egg is suitable. It is cut into pieces and covered with a glass jar along with a coin placed on its edge. Patination of coins using this method is quick: the color change is visible to the eye. However, if the color does not suit you, it will not be easy to wash off the patina.

When everything happens by itself

If you put patina on bronze coins, then you can use methods suitable for silver. But there is a way to patina bronze coins naturally. To do this, bronze coins must be constantly exposed to sunlight. The sun helps to obtain a beautiful and even patina on bronze in one and a half to two years. Of course, this method cannot be called an express method, but you don’t have to wait half a century either. Returning to copper, let's remember the advice to keep cleaned coins in a jar of matches. The results are ambiguous, but you can experiment with inexpensive copies. At home, they try patination with wood. Certain types of wood produce tannins that help produce "cabinet" patina.

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While searching for coins or collecting them, you have probably heard this strange word more than once. If you have no idea what it means or want to learn more about it, then this article is for you.

Patina is an oxide-carbonate deposit on the surface of a metal, formed as a result of exposure to the external environment. The patina on a coin emphasizes its antiquity, makes it more beautiful and even more expensive. Especially if it is natural.

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Natural patina is a common process of oxidation of metal, which results in the formation of oxides, the same as rust on iron. But this is a little different. The natural patina on a coin takes a very long time to form. Decades, or even centuries. This coating not only indicates the authenticity of the coin, but also even protects it from destructive corrosion. Also, based on the patina, we can safely say that no action was taken on the coin: they did not try to clean it, did not raise the relief, and that the coin was preserved in the form in which it is.

There is also an artificial patina made using chemicals that accelerate metal oxidation reactions. But it is very difficult to replicate natural patina. I would even say that it is impossible. But still, sometimes you have to resort to patination of coins in order to give an ancient and noble appearance to a freshly cleaned coin that still sparkles with bare metal.

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