What Is a Coin?
Coin is an object that is used as a unit of value in a transaction. It can be made of any metal and may also have a design on one or both sides. Most coins are round in shape. A coin can be engraved, pressed, cast or stamped. Some are made of only gold or silver, while others are a combination of metals and other materials.
In order for a society to function effectively, it must have some standard of value for the goods and services it produces and consumes. Historically this standard has been metal, usually in flat, round pieces called coins. Coins have been produced in a variety of metals over the centuries and have varied in size, design, and weight.
A coin can be stamped with an image of a monarch, other authority figure, or national emblem. The side of a coin carrying this image is called the obverse (colloquially, heads); the other side is the reverse (colloquially, tails). On most coins the year of minting is shown on the obverse; however, some Chinese coins, most Canadian and British coins prior to 2008, all Mexican coins and the American quarter and dollar before 1982 do not have the year of minting printed on them. A coin can have a space on the edge, called the exergue, which is left blank or contains a privy mark or other decorative feature.
The value of a coin depends on its weight, material, and design. Some coins are more valuable than others because of the quality of their metal or their artistic design. It is also important to consider how many of a coin’s sides are visible when determining its value.
Coins have been used for thousands of years as a means of exchange, and their history can tell us much about the past. For example, a study of the decline in value of the coins of the ancient world may illuminate periods of national financial distress, while a comparison of the coinage of different dynasties provides insight into the development of various artistic styles. The coinage of the kings of Greece, the Greco-Bactrian emperors, and the tetrarchy of the medieval world all offer miniature likenesses of numerous sculptural and architectural masterpieces that are now lost.
Modern coins are often made of a base metal, and their value is determined by laws governing their use in trade and for international payment. In this respect they are similar to paper currency, which is no longer backed by any amount of physical metal and is instead simply a token with a specified value. The difference in value between a metal coin and its paper counterpart is often minimal, except for collectors’ values.