A coin is a small, flat, round piece of metal or plastic used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order to facilitate trade. They are most often issued by a government. Coins often have images, numerals, or text on them. Obverse and its opposite, reverse, refer to the two flat faces of coins and medals. In this usage, obverse means the front face of the object and reverse means the back face. The obverse of a coin is commonly called heads, because it often depicts the head of a prominent person, and the reverse tails.
Coins of the United States dollar were first minted in 1792. New coins have been produced annually and they make up a valuable aspect of the United States currency system. Today, circulating coins exist in denominations of 1¢, 5¢, 10¢, 25¢, 50¢, and $1.00. Also minted are bullion and commemorative coins. All of these are produced by the United States Mint. The coins are then sold to Federal Reserve Banks which in turn are responsible for putting coins into circulation and withdrawing them as demanded by the country's economy.
Hammered coinage is the most common form of coins produced since the invention of coins in the first millennium BC until the early modern period of c. the 15th–17th centuries, contrasting to the cast coinage and the later developed milled coinage.
Roman currency for most of Roman history consisted of gold, silver, bronze, orichalcum and copper coinage. From its introduction to the Republic, during the third century BC, well into Imperial times, Roman currency saw many changes in form, denomination, and composition. A persistent feature was the inflationary debasement and replacement of coins over the centuries. Notable examples of this followed the reforms of Diocletian. This trend continued into Byzantine times.
Commemorative coins are coins issued to commemorate some particular event or issue with a distinct design with reference to the occasion on which they were issued. Many coins of this category serve as collectors items only, although some countries also issue commemorative coins for regular circulation.
The dollar coin is a United States coin with a face value of one United States dollar. Dollar coins have been minted in the United States in gold, silver, and base metal versions. Dollar coins were first minted in the United States in 1794.
The history of ancient Greek coinage can be divided into four periods: the Archaic, the Classical, the Hellenistic and the Roman. The Archaic period extends from the introduction of coinage to the Greek world during the 7th century BC until the Persian Wars in about 480 BC. The Classical period then began, and lasted until the conquests of Alexander the Great in about 330 BC, which began the Hellenistic period, extending until the Roman absorption of the Greek world in the 1st century BC. The Greek cities continued to produce their own coins for several more centuries under Roman rule. The coins produced during this period are called Roman provincial coins or Greek Imperial Coins.
A mint is an industrial facility which manufactures coins that can be used as currency.
The Ban Liang was the first unified currency of the Chinese empire, introduced by the first emperor Qin Shi Huang around 210 BC. It was round with a square hole in the middle. Before that date, a variety of coins were used in China, usually in the form of blades or other implements, though round coins with square holes were used by the State of Zhou before it was extinguished by Qin in 249 BCE.
In numismatics, token coins or trade tokens are coin-like objects used instead of coins. The field of token coins is part of exonumia and token coins are token money. Tokens have a denomination either shown or implied by size, color or shape. "Tokens" are often made of cheaper metals: copper, pewter, aluminium, brass and tin were commonly used, while bakelite, leather, porcelain, and other less durable materials are also known.
Silver coins are considered the oldest mass-produced form of coinage. Silver has been used as a coinage metal since the times of the Greeks; their silver drachmas were popular trade coins. The ancient Persians used silver coins between 612–330 BC. Before 1797, British pennies were made of silver.
Ancient Chinese coinage includes some of the earliest known coins. These coins, used as early as the Spring and Autumn period (770–476 BCE), took the form of imitations of the cowrie shells that were used in ceremonial exchanges. The same period also saw the introduction of the first metal coins; however, they were not initially round, instead being either knife shaped or spade shaped. Round metal coins with a round, and then later square hole in the center were first introduced around 350 BCE. The beginning of the Qin Dynasty (221–206 BCE), the first dynasty to unify China, saw the introduction of a standardised coinage for the whole Empire. Subsequent dynasties produced variations on these round coins throughout the imperial period. At first the distribution of the coinage was limited to use around the capital city district, but by the beginning of the Han Dynasty, coins were widely used for such things as paying taxes, salaries and fines.
Cash was a type of coin of China and East Asia, used from the 4th century BC until the 20th century AD, characterised by their round outer shape and a square center hole. Originally cast during the Warring States period, these coins continued to be used for the entirety of Imperial China. The last Chinese cash coins were cast in the first year of the Republic of China. Generally most cash coins were made from copper or bronze alloys, with iron, lead, and zinc coins occasionally used less often throughout Chinese history. Rare silver and gold cash coins were also produced. During most of their production, cash coins were cast, but during the late Qing dynasty, machine-struck cash coins began to be made. As the cash coins produced over Chinese history were similar, thousand year old cash coins produced during the Northern Song dynasty continued to circulate as valid currency well into the early twentieth century.
The English shilling was a silver coin of the Kingdom of England, when first introduced known as the testoon. It remained in circulation until it became the British shilling as the result of the Union of England and Scotland to form the Kingdom of Great Britain in 1707.
Spade money was an early form of coin and commodity money used during the Zhou dynasty of China. Spade money was shaped like a spade or weeding tool, but the thin blade and small sizes of spade money indicate that it had no utilitarian function. The earlier versions of spade coins tended to have a fragile, hollow socket, reminiscent of a metal shovel. Later versions of spade money had this socket was transformed into a thin, flat piece, and over time, inscriptions were added to the spade coins to mark their denominations. Several versions of spade money circulated across the Chinese Central Plains during the Zhou dynasty period until they were abolished by the Qin dynasty in 221 BC in favour of the Ban Liang cash coins.
The Yuan dynasty was a Mongol-ruled Chinese dynasty which existed from 1271 to 1368. After the conquest of the Western Xia, Western Liao, and Jin dynasties they allowed for the continuation of locally minted copper currency, as well as allowing for the continued use of previously created and older forms of currency, while they immediately abolished the Jin dynasty's paper money as it suffered heavily from inflation due to the wars with the Mongols. After the conquest of the Song dynasty was completed, the Yuan dynasty started issuing their own copper coins largely based on older Jin dynasty models, though eventually the preferred Yuan currency became the Jiaochao and silver sycees, as coins would eventually fall largely into disuse. Although the Mongols at first preferred to have every banknote backed up by gold and silver, high government expenditures forced the Yuan to create fiat money in order to sustain government spending.
Qing dynasty coinage was based on a bimetallic standard of copper and silver coinage. The Manchu-led Qing dynasty was established in 1636 and ruled over China proper from 1644 until it was overthrown by the Xinhai Revolution in 1912. The Qing dynasty saw the transformation of a traditional cash coin based cast coinage monetary system into a modern currency system with machine-struck coins, while the old traditional silver ingots would slowly be replaced by silver coins based on those of the Mexican peso. After the Qing dynasty was abolished its currency was replaced by the Chinese yuan of the Republic of China.
Although the vast majority of coins are round, coins are made in a variety of other shapes, including squares, diamonds, hexagons, heptagons, octagons, decagons, and dodecagons. They have also been struck with scalloped (wavy) edges, and with holes in the middle. Coins in the shape of polygons often have rounded edges or are Reuleaux polygons.
Mother coins, alternatively known as seed coins or matrix coins, were coins used during the early stages of the casting process to produce Chinese, Japanese, Korean, Ryukyuan, and Vietnamese cash coins. As cash coins were produced using sand casting mother coins were first produced to form the basis for all subsequent cash coins to be released into circulation. Under the Han dynasty in China mints started producing cash coins using bronze master moulds to solve inconsistencies in circulating coins, this only worked partially and by the sixth century mother coins were introduced to solve these inconsistencies almost completely. The Japanese adopted the usage of mother coins in the 600s and they were used to manufacture cast Japanese coins until the Meiji period. The mother coin was initially prepared by engraving a pattern with the legend of the cash coin which had to be manufactured. In the manufacturing process mother coins were used to impress the design in moulds which were made from easily worked metals such as tin and these moulds were then placed in a rectangular frame made from pear wood filled with fine wet sand, possibly mixed with clay, and enhanced with either charcoal or coal dust to allow for the molten metal to smoothly flow through, this frame would act as a layer that separates the two parts of the coin moulds. The mother coin was recovered by the people who cast the coins and was placed on top of the second frame and the aforementioned process was repeated until fifteen layers of moulds had formed based on this single mother coin. After cooling down a "coin tree" (錢樹) or long metallic stick with the freshly minted cash coins attached in the shape of "branches" would be extracted from the mould and these coins could be broken off and if necessary had their square holes chiseled clean, after this the coins were placed on a long metal rod to simultaneously remove the rough edges for hundreds of coins and then these cash coins could be strung together and enter circulation.
Standard cash, or regulation cash coins, is a term used during the Ming and Qing dynasties of China to refer to standard issue copper-alloy cash coins produced in imperial Chinese mints according to weight and composition standards that were fixed by the imperial government. The term was first used for Hongwu Tongbao cash coins following the abolition of large denomination versions of this cash coin series.
