$USDC A coin is a small, flat, round piece of metal used as currency. Coins are typically made from metals like copper, nickel, or silver and have been used for centuries as a medium of exchange. Each coin usually has two sides: one featuring a symbol, portrait, or design representing a nation or institution, and the other showing its denomination. Coins are durable and convenient, often used alongside paper money. Collectors, called numismatists, seek rare and historic coins as valuable artifacts. Despite the rise of digital payments, coins remain an essential part of economies worldwide, symbolizing history and culture.