Coins

Coins are small, flat pieces of metal or alloy issued by a government as money with a stated value. They are produced by a national mint and intended for circulation in everyday commerce, though many coins are also issued for collectors or commemorative purposes. Modern coins typically feature a country's national symbols, a portrait of a ruler or official, the denomination, year of issue, and often security features on the edge or surface.

The history of coinage begins with metal pieces used as markers of value in ancient kingdoms, with early examples appearing in Lydia, China, and elsewhere. Standardized coinage spread through Greece and Rome and continued into medieval and modern times, culminating in centralized minting by sovereign states. In many economies, coins and banknotes supplemented each other until widespread electronic payments reduced demand for smaller denominations in some regions.

Coins are usually made from metal alloys such as copper, nickel, zinc, bronze, or brass, with silver or gold used for higher values or collector pieces. They have obverse and reverse designs, often with a portrait on the obverse and a national emblem or denomination on the reverse. Edges may be smooth, reeded, or inscribed, and mint marks indicate where they were produced.

Minting involves creating dies, preparing blank planchets, and striking them at high pressure. Denominations vary by country, from cent or pence to larger units, and many currencies use a decimal system. Numismatics is the study and collection of coins, focusing on rarity, condition, mint errors, and historical significance. Counterfeiting remains a concern and is addressed by design features and authentication practices.