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A coin (v. Latin moneta ) is usually a circular and relatively thin, embossed or previously poured means of payment and thus a sub-form of money . It almost always consists of a metal alloy . In numismatics, square coins are called cliffs and the as yet unminted coin blank is called round , plate or, earlier, flint . Today, coins are almost always made by minting coins . In a figurative sense, the term “coin” also stands for a mint . According to their function, coins can be divided into course coins (for everyday use of money), commemorative coins (as collector's items to commemorate an event) and investment coins (as precious metal investments ).

Must be distinguished from marks or signs, the most diverse as coin-like imprints purposes fulfill, such as a token , token , Ration Card , cloakroom ticket or token .

History of Coin

Beginnings in Asia Minor, Greece and China

The first finds of presumed metal money come from the Mediterranean region and date around 2000 BC. These are miniature pets made of bronze .


The first coins were made in the Lydian Empire between 650 and 600 BC. Issued as means of payment ( see also: Alyattes II and Croesus ). These were misshapen chunks of electron , a naturally occurring gold-silver alloy, initially without a picture. Pictorial representations on coins came around 600 BC. Chr. On. This was followed by gold coins of various sizes and values.


Stater from Corinth (head of Athena , 4th century BC)

The first silver coins were made around 550 BC. In Asia Minor and on the Greek island of Aegina . Until about 400 BC BC the coin prevailed against barter throughout Greece. However, there was no uniform coin system, but several regions, each of which was dominated by a coin family. Slowly, however, the 17 gram Attic tetradrachm with its parts (e.g. hemidrachm, obolos, Latin: obolus , hemiobolos, tetartemorion) and seldom larger units ( decadrachm = 10 drachms) established a dominant position.

The first bronze coins were minted from the second half of the 5th century BC. They were at the same time the first divisional coins , i.e. H. for them the face value was higher than the metal value.

The representation of rulers on coins only prevailed in Greece and in the Diadochian empires after Alexander the Great . Silver remained the defining raw material.


In ancient China, cowrie money was the first known means of payment. During the Shang dynasty , the use of simple pieces of bronze emerged and under the late Zhou dynasty (around 500 BC) the use of knife- and spade-shaped coins can be documented for the first time. The first emperor Qin Shi Huangdi unified in the course of the unification of the empire in 221 BC. The money in favor of a common copper currency from round perforated coins ( cash ), a form that was then retained for more than 2000 years.

Roman coins

Roman aureus of Septimius Severus (193-211)

The first round coins of the Roman Republic date from the 3rd century BC and were struck from copper or bronze , but the large, one- pound pieces of copper, the As ( Aes grave ), were cast. Payment was first made with the bronze cast regulation, the Aes rude , and then with standardized bronze cast bars , the Aes signatum . Motifs such as bulls, pigs, chickens, but also shields, herald's staff, anchors, trident, weapons or liturgical objects (sacrificial bowl) with ornaments were mostly depicted on both sides of this bar. After the bronze ingots had lost their validity, many early Roman As and As part coins, which followed the bar money, usually had a ship's hull ( prora ) as a motif on the reverse , which was to commemorate the conquest of the Antium fleet , and on the front various images of gods, such as B. Vulcanus , the god of blacksmithing . The first Roman silver coin ( quadrigatus ), in the Greek drachma style, was made around 269 BC. Beaten. Silver minting on a grand scale began in Rome around 211 BC. With the denarius . Julius Caesar was the first living person to be depicted on a Roman coin in the full head profile "as God" (44 BC).

During the imperial era , coins made of gold ( aureus ), silver (denarius), brass ( sesterce and dupondius ) and copper ( As ) were struck. During the time of the soldier emperors, the silver antoninian slowly asserted itself against the denarius. Under Emperor Diocletian , new denominations were added, such as the Argenteus and the coins Nummus and Follis . Overall, Roman coinage deteriorated visibly under the emperors. From the beginning of the 4th century, the jeweled diadem prevailed against the original laurel wreath on the front of the coins. The faces of the emperors were depicted worse and worse, which shows that the diadem was more important to the emperors on their coins than a neat representation. Finally, in the Western Roman Empire, more and more spelling errors appeared on the coins, as most of the minters could only speak and write Latin poorly. The Eastern Roman coins quickly broke away from the Imperial Roman models and developed their own formal language.

The Germanic states of the Migration Period sometimes minted coins that were based either on the Western or Eastern Roman model.

The middle age

From late antiquity to the early Middle Ages , the circulation of coins in Europe declined sharply. Barter increased, and major financial transactions were often made in uncoined metal. The standard currency was the Byzantine solidus and the siliqua with the various subdivisions. The Germanic rulers who established new empires on the soil of the Western Roman Empire mostly recognized the minting authority of the Byzantine rulers and imitated their minting. Only occasionally did they put their own name, monogram or even their portrait on the coins.

Charlemagne carried out a coin reform around 792 to 793 , which led from the gold and silver currency to the unified silver currency. See schilling . The denarius or pfennig was newly introduced as the almost exclusively minted coin. It was preceded by the consideration that gold could almost only be obtained through long-distance trade, while silver was abundant in Europe north of the Alps. Therefore, Karl canceled the gold link in money and introduced the silver denarius as a binding currency throughout the empire. The basic weight of the coin was set at 367 g, from which 240 pfennigs (denarii) were struck, which was laid down in Karl's coin order. A solidus or shilling was 12 denarii; one pound (libra), the weight of which was increased compared to the ancient measure, corresponded to 20 solidi. The Anglo-Saxon King Offa von Mercien took over this regulation at the same time, which was in force in England until 1971. (See also Sachsenpfennig - Münzfuß .)

Hochrandpfennig ( Sachsenpfennig ) 985–1000, based on the Carolingian model. Temple on the front, cross on the back, a ball in each corner.
Ludwig III. (1172–1190), Landgrave of Thuringia, equestrian bracteate around 1180, Gotha or Eisenach
Elector Ernst and Duke Albrecht , half sword coin, year 1482, mmz. Shamrock, minted in the Zwickau Mint and the Schneeberg Mint

In the Holy Roman Empire, the originally royal minting law increasingly expanded to include other secular and spiritual dignitaries, which resulted in a large number of different versions of the pfennig (“ regional pfennig ”) and a general reduction in the silver content of the coins.

From the middle of the 12th century to the 14th century, bracteates were the predominant type of coin in almost all of German-speaking countries (with the exception of the Rhineland and the Alpine region). These thin silver penny coins, embossed on one side, continued the process of weight loss of the old pennies. Bracteates were from time to time "disreputable", that is, declared invalid and reclaimed from their owners in order to exchange them for a smaller amount of new coins. The discount could be up to 25%. This was a common form of tax collection at the time. In order to create stable conditions for trade and industry, it was mainly the trading cities that were interested in taking coinage into their own hands. Several cities took advantage of the opportunity to lease the mint or to purchase it in order to mint their own coins, the so-called perpetual pennies , which were not subject to the annual coin revocation . (See also: Sächsische Münzgeschichte # Bracteatenzeit and the dynasty coins , for example the Doninian bracteates .)

Gold coins were rarely struck in the High Middle Ages. It was not until the 13th century that gold coinage began to increase. This development came from the Italian trading cities. In France and England gold coins were more common and the individual pieces were significantly larger than in the empire. As a further development in the 13th century, the Groschen appeared in Germany as a larger silver coin. For the first time, the coin images of the groschen also increasingly showed princes of the respective territory.

The year 1356 was a crucial date in German minting law. The coin rack and thus the unrestricted right to coin was laid down for all electors of the Holy Roman Empire in the Golden Bull of Charles IV . The electors derived the right to mint gold coins from this.

The privilege of minting gold guilders was first granted to the imperial-free city of Lübeck in 1340 . The prince-bishops of the Electorate of Trier and the Electorate of Cologne were granted this privilege in 1346 by Charles IV when he was crowned Roman-German king . They founded a mint association in 1372 and had the gold guilder and, as a common silver coin, the white pfennig minted with a fixed fineness . In 1385/86 the Rhenish prince-bishops and the electors of Kurmainz and the Electoral Palatinate founded the first Rheinische Münzverein , which was followed by others. The Rheinische Münzverein had the Rhenish guilder minted in gold. This was the basis for many regional currencies throughout the Holy Roman Empire and, on a financial level, the “unifying bond” of the empire.

Until 1871, the history of coins in Germany was characterized by great diversity, as many countries spent their own money.

Modern times

Coin hitter of the early modern period
Taler with the portrait of Rex Romanorum Maximilian I (1486–1519)
Stone entrance ticket office in Zrinski Castle (Northern Croatia) for coins that subordinates used to pay to enter the castle.

In coinage, the modern age begins with the creation of the taler . A large silver coin, the Uncialis or Guldiner, was struck for the first time in 1486 under Archduke Sigismund (Tyrol) . The first large silver coin minted in large numbers was the Saxon silver guilder, minted according to the model of the Tyrolean guldiner. This large silver coin, later called the Klappmützentaler , was struck for the first time in 1500 in the Annaberg / Frohnau mint and possibly in the Wittenberg mint . The Saxon silver gulden (thaler) was the model for the guldengroschen minted in the Bohemian Joachimsthal , which was soon called the thaler. The taler spread over the whole world in the following centuries and represents the first case of a complete replacement of all models of previous types of coins. Since its production quickly spread over numerous territories, the respective sovereigns gave "their" talers an individual design, the reached a high quality in the course of technical and artistic progress. Occasionally, multiple thalers , thick thalers and wide thalers were struck. From the 17th century, city views appeared as a new motif.

The large number of small coins below the thaler increasingly lost their fineness. This development reached its climax in the days of the tipper and luffing machine during the Thirty Years' War . In addition, for the first time since late antiquity, copper coins were minted as divisional coins in the 17th century . The golden ducats prevailed for the sale of valuable goods . Numismatic rarities are river gold ducats .

Arabic names for European coins, which were spread through the Levant trade in Arab states, are decorative epithets that mostly relate to the coin image. The Maria Theresa thaler was called Abu Kush (father of the bird) or Abu Noukte (father of pearls), as an eagle and pearls could be seen on the empress's diadem. See → trade coin . The Dutch lion thaler was called Abu Kelb (father of the dog), the Spanish eight-reales piece with a four-field coat of arms shield Abu Taka (father of the window).

In the 17th and 18th centuries, a particularly large number of trade coins were minted. The bank teller , decided in Hamburg in 1695, was intended to prevent the Dutch money changers from enriching themselves with the acceptance of the higher value Reichstaler. Overall, in the history of coins up to modern times, the similar process of depreciation has been shown again and again: While money in the form of coins initially consisted of valuable material (gold, silver) and their exchange value corresponded to the value of this material (fully-fledged coins) , later Coins were produced whose material value was below their exchange value by making the coins smaller and lighter, reducing the fineness or using less valuable materials (inferior coins) .

The fugio cent , issued in 1787, was the first official coin of the United States of America.

Features of coins

1 ruble Prednistrovien obverse, plastic currency coins

Coins are state- approved means of payment. Modern coins usually have three inscriptions: the country (or community of states), the value (made up of the nominal and currency unit) and the year of issue. But there are exceptions: the year is missing for some older, exotic, small units (for example all cash coins from Travancore , minted until 1949). There are also exceptions for taler coins. For example, the Saxon butterfly coins only bear the monogram of the mint owner and a value in groschen.

Features of coins were sometimes used for manipulative purposes. For example, omitting the year of issue may also have been a calculation. When the Imperial Minting System was introduced, some minters did not stamp the year in order to be able to mint it unnoticed for a while after a lighter coin rate, as did, for example, the mistress of Jever with the Danielstalers .

The Swiss centimes (sub-unit of the Swiss franc ) only carry the nominal, without specifying the currency unit . It is even more drastic with the British Crowns from the minting years 1965–1971. These carry neither a nominal nor the indication of the currency unit. In all British coins with Elizabeth II the country is not indicated, in the case of their predecessors only as part of the title of the monarch. The first coins in Germany after 1945 had the inscription or legend " Bank deutscher Länder ". In the case of euro coins, there is usually no country information either, only an identifier for the country on the reverse of the coin.

The front ( obverse ) of the coin is usually where the head of the ruler or the coat of arms of the republic can be seen. The back (the lapel ), however, is usually on the side with the value. In between is the edge of the coin , which can be grooved or labeled and usually protrudes a little over the surface of the coin ("edge bar"). The inscription of a coin is called a legend in numismatics . However, there are also coins that have neither a front nor a back (see Schmalkaldischer Bundestaler ).

The mint master's marks on the coins appear from the late Middle Ages. They were largely replaced in the second half of the 19th century by the mintmark in the form of a letter to denote the mint. Sometimes there is also the signature of the coin engraver or just the artist's signature on coins . The mint master's mark must therefore not be confused with the coin signature .

Differentiation from medals

While the issuance of coins is a privilege of the state, medals can also be produced privately. Mints that are not intended as legal tender are often added to the medals. Something in between are the so-called pseudo - coins , which are de jure means of payment, but are minted by private companies for the international collector's market and have no de facto monetary function. Conversely, there are also coin-like issues such as emergency coins and tokens , which were actually used as a means of payment, but were not issued by the authorized government agencies. However, they were partially tolerated by the state as a substitute money symbol, such as the various German and Austrian emergency money issues in the form of coins and banknotes after 1914 to 1923. Today, medals are not allowed to have valid currency denominations and face values . See also investment coins in addition .

A borderline case is documented using the example of the historically and artistically significant Locumtenenstaler ( vicariate coin ). These are guldengroschen (thalers), which were also made as medals with a higher relief, but also in thaler weight, i.e. in the legal coinage rate, and served as gifts for favorites. In catalogs, both types are therefore often referred to as guilder groschen, although only those with lower relief are actually coins. At this time (beginning of the 16th century), the distinction to medals can only be recognized by the type of embossing, the high relief typical of medals.

Another borderline case is the 1 billion mark piece from the province of Westphalia, a coin with a “medal character”. The coin of the Landesbank of the Province of Westphalia, minted as emergency money in 1923, was only issued in 1924 after the end of inflation as a memento of the difficult times.

The Gluckhennentaler usually appears as a medal. As a gold mark in the multiple ducat weight, it can be circulated, i.e. a coin.

Punching coins

In some countries, such as Norway and Denmark , various small coins have been punched out in the middle so that they can be differentiated more quickly and better from higher value coins. The cash coins known in Asia ( Japan , China ) , on the other hand, were already cast in this form. In two other cases - Australia and the Caribbean Islands - the cores were punched out of silver coins and these in turn were put into circulation as separate coins.

Amulet coin (here the Mansfeld Georgstaler )

There can be very different reasons for punching a coin (usually afterwards). Holes were often made so that the coin (or medal ) could be worn on a chain as jewelry or as an amulet ( amulet coin ). A subsequent perforation can also occur if certain metals, especially precious metals, have been removed from the coin for enrichment, such as currency coins or coins whose market value is below the value of the metal. The perforation makes the coin unattractive for collectors.

Another use of punching was to permanently devalue counterfeit money.

Coin material

In ancient times the metals and alloys gold , electron , silver , billon , copper , bronze , potin and brass or aurichalcum were used almost exclusively for the production of coins . From the Middle Ages until around 1850, only gold, silver and copper and their alloys were allowed for coinage in Germany. Bronze and especially brass were required by law for tokens and arithmetic pennies because of their color to distinguish them from coins. As early as around 1860, other metals such as iron , nickel , zinc , aluminum and chrome steel were increasingly used . A special, newer alloy that also satisfies aesthetic criteria is Nordic gold . The pure metals, especially gold, silver, copper and aluminum, were and are almost always alloyed with other metals for reasons of abrasion resistance . The natural alloy electron , a gold-silver alloy, played a special role in the oldest ancient coins, since electron was originally regarded as an independent pure metal. Copper in particular is an important component of current and earlier coin alloys because of its antibacterial effect and good availability. The most common coin alloy today is cupronickel , but bronze and brass alloys are also not uncommon. Pure metals such as tin , zinc and, from a health point of view, lead , which were therefore often only used as emergency money , have not proven themselves . The relative proportion of the precious metal in the coin alloy was determined by the so-called coin base - the metallurgical composition was determined by chemical-analytical detection reactions .

Detail from a 20 cent coin

For several decades there have also been coated coins ("sandwich"), for example cupronickel as a coating on a nickel core (so-called "machine coins" with a defined magnetic core) or the 1- pfennig (from 1950 to 2001) and 2-pfennig coins (1967-2001), which consisted of copper-clad iron. The round blanks combination of “ring” and “pill” made of different colored alloys are now common, for example with 1 and 2 euro coins.

Coins whose market value is determined by the intrinsic value (metal value) are called Kurant coins . This applied earlier (generally until 1914) to most precious metal coins, the precious metal content of which was significantly greater than 50 percent. The 5, 10 and 20 gold mark pieces that were issued between 1871 and 1915 had a fineness of 900 ‰. The same was true of the silver coins of that time. A 5-mark piece made of gold weighed 1.991 grams, and one made of silver 27.777 grams. The intrinsic value of both coins was the same and corresponded to the face value.

As a token coins are called coins whose nominal value does not match the value of the metal. In the past, these were often made of a billon alloy or just copper. The material value of all current coins in circulation is always below the face value and they are therefore deciduous coins. This applies to all current circulation coins and many commemorative coins , as their value is only covered by state guarantees, which is what is known as credit money . In contrast, see investment coins .

Coinage metals

  • Gold : The most important coin metal for high face value coins. It was mostly alloyed with copper for circulation coins in order to achieve a better hardness. Today it is only used for commemorative coins, medals and investment coins, mostly with a very high fineness. It serves as the main component of the electron alloy .
  • Silver : Since the 6th century BC With gold one of the oldest coinage and barter metals. The vast majority of modern commemorative coins, medals and investment coins consist of silver, mostly of high fineness. Silver is a valuable component of the billon alloy .
  • Copper : In addition to gold and silver, it used to be the third most common, today the most common base coin metal. Due to its excellent alloying properties, copper is used almost exclusively for minting circulation coins in alloyed form, e.g. B. in bronze , brass and nickel silver . Small German dividing coins such as pfennigs and hellers were often made of pure copper until around 1871. Later (Reichs-) pfennigs consisted of copper with a small amount of tin and zinc to harden the copper.
  • Nickel : A light silver, shiny, particularly hard metal. Nickel is an important alloy metal in modern coinage ; however, it was previously minted as a pure nickel coin, e.g. B. 25-pfennig piece from 1912.
  • Aluminum : A very light and soft coin metal that has a light silver sheen. In its pure form, aluminum is less suitable for circulation coins because of its rapid wear and tear. It is therefore used today in alloys, e.g. B. with a low copper and magnesium content (up to 3%), hardened; Also named component of aluminum-bronze coin alloys.
  • Zinc : a cheap, gray and soft metal. Used for coin production in (post) war and emergency times, e.g. B. 5 groschen piece from Austria after 1945, as well as an important alloy component.
  • Eisen : Was already in the 3rd century BC. Used in China to make coins. Because of the rapid corrosion , it was only used in times of need. Often the corrosion protection was then through a surface passivation , e.g. B. as galvanizing, increased.
  • Tin : Tin is used quite often as an alloy component, but only rarely as a light, soft and pure coin metal; it used to be pure, e.g. B. to remember special events for so-called "price increases, plague and storm medals", related.
  • Lead : Unsuitable as a pure, bluish-gray coin metal because it is too soft and susceptible to moisture. Only in antiquity were coins made of lead occasionally and in the Middle Ages seals were made as papal bulls . Coin counterfeiters often resorted to lead to imitate silver coins. It was also used as the core of so-called Galvanos (special coin copies), and until recently it was also often used as a calibration seal in the form of seals , e.g. B. on electricity meters.
  • Nickel silver : A shiny silver-white alloy made from 47–64% copper, 10–25% nickel, 15–42% zinc
  • Niobium : The rare, shiny gray niobium was discovered in 1844 by Berlin professor Heinrich Rose . The high-purity niobium (999), which has recently been used for the first time for coin production, is extracted in an extremely time-consuming and expensive process. It is precisely its extraordinary property of being able to change the color through special processing that makes this rare metal particularly attractive for numismatists and coin collectors.
  • Platinum : A light gray, shiny silver metal that is not very hard and can therefore only be used to a limited extent for coinage. True platinum circulation coins were only issued in Russia in the early 19th century. Today it is used as a valuable medium for investment coins.
  • Palladium : A rare, silvery-white glossy coin metal that belongs to the group of platinum metals and is used to manufacture investment coins.
  • Tombak : alloy made from 70–90% copper and 10–30% zinc. Used z. B. for plating the 5 and 10 pfennig pieces of the Bundesbank from 1949 to 2001.

Other materials

  • From the end of the 18th century until around 1865, porcelain coins were used in Siam instead of metal money as gambling den money ( tokens ). Furthermore, white bisque and more often brown Böttger stoneware was used for emergency money with currency denominations after the First World War , but this was intended more for collectors than for daily circulation.
  • Pieces of leather were occasionally used as coins or as "emergency money tokens".
  • Round pieces of cardboard or, today, also plastic materials were / are used for emergency coins or for children's play money. This emergency money is known as the "money sign".
  • In 2014, plastic ruble coins were put into circulation in the internationally not recognized Transnistria .
"Blue Planet" coin
Germany's first 5 euro coin with a polymer ring
  • In the first half of 2016, a 5-euro commemorative coin “Planet Earth” with a blue, translucent polymer ring was issued in Germany for the first time . This is also the first official coin with a polymer ring in the world.


In the member states of the European Monetary Union , according to EC Regulation No. 974/98 of the Council of May 3, 1998, nobody has to accept more than fifty coins in one payment (with the exception of the issuing authority and the persons named in Section 3 of the Coin Act ); see also the article legal tender .

collect coins

DM set of coins in "mirror finish"

Coins are also collected in a similar way to postage stamps , beer mats , objets d'art or similar objects. In addition to their market value, they can also acquire collector's value. This depends on the supply (mintage of the coin) and demand. Demand is determined by the interest of collectors, but also by price fluctuations, fashion waves, current political events and similar effects. Extremely rare and nonetheless in high demand are therefore particularly valuable, such as very old and nevertheless very well preserved coins. The currently most expensive coin in the world in terms of collector's value is the 1794 Flowing Hair silver dollar. On January 24, 2013, such a coin reached the record price of $ 10,016,875.


The skin takes on contact with copper or iron-containing coins a strange musty smell of, usually associate the people "metallic" with. The cause of the characteristic smell could only be clarified in 2006. The metals cause a rapid chemical reduction of the lipid-based components on the surface of the skin, which results in ketones and aldehydes . The latter in turn are responsible for the typical “metal smell”.

See also

Web links

Commons : Coins  - Collection of Images
Wiktionary: coin  - explanations of meanings, word origins, synonyms, translations
Wikiquote: Coin  Quotes


  • Philip Grierson : Coins of the Middle Ages. (German translation by Alfred P. Zeller) Munich 1976 (= The World of Coins , 4).
  • Wilhelm Jesse : Source book on the history of coins and money in the Middle Ages (with 16 plates). Halle on the Saale in 1924; Reprint Aalen 1968.
  • Helmut Kahnt, Bernd Knorr: Old measures, coins and weights: A lexicon. Mannheim / Vienna / Zurich 1987.
  • Fritz Verdenhalven : Old measures, coins and weights from the German-speaking area. Neustadt an der Aisch 1968.

Individual evidence

  1. Helmut Kahnt, Bernd Knorr: Old dimensions, coins and weights. A lexicon. Bibliographisches Institut, Leipzig 1986, licensed edition Mannheim / Vienna / Zurich 1987, ISBN 3-411-02148-9 , p. 387.
  2. a b The coins and seals of the Archbishops of Trier. 1973, published by Stadtsparkasse Trier
  3. Heinz Fengler, Gerd Gierow, Willy Unger: transpress Lexikon Numismatics. Berlin 1976, p. 87.
  4. Heinz Fengler: "Introduction" In: 700 years of coinage in Berlin. Berlin 1976, p. 20; see. New High German translation of the Golden Bull of 1713, Chapter X - Von der Müntz ( full text in Wikisource ) and commentary by Karl Zeumer : The Golden Bull of Emperor Charles IV (Part 1). Hermann Böhlaus successor, Weimar 1908, p. 51 f. ( Full text in Wikisource ).
  5. Arthur Suhle: German monetary history from the beginnings to the 15th century. P. 167.
  6. Arthur Suhle: German monetary history from the beginnings to the 15th century. P. 174.
  7. Heinz Fengler, Gerhard Gierow, Willy Unger: Transpress lexicon numismatics. Berlin 1976, p. 316.
  8. Günter Schön: Weltmünzkatalog. 1991, p. 410.
  9. : Paul Arnold: Walther Haupt and his "Sächsische Münzkunde". In: Numismatic Hefte Dresden, No. 20, 1986, p. 57.
  10. ^ Peter Menzel: German emergency coins and other money substitute stamps 1873-1932. Berlin 1982, p. 482.
  11. Helmut Kahnt, Bernd Knorr: Old dimensions, coins and weights. A lexicon. Bibliographisches Institut, Leipzig 1986, licensed edition Mannheim / Vienna / Zurich 1987, ISBN 3-411-02148-9 , p. 381 (amulet coin) .
  12. Transnistria to Introduce Plastic Circulation Coins (English)
  13. Federal Ministry of Finance - press releases - world novelty: 5 euro collector's coin “Planet Earth” with a blue ring. Retrieved January 29, 2016 .
  14. Research Highlights. In: Nature . Volume 444, p. 4, November 2, 2006 on an article in Angew. Chem. Int. Ed. Volume 45 (2006), pp. 7006-7009.