A gold coin is a piece of currency made primarily from gold, often used for trade and investment. Historically, gold coins have been minted by various civilizations, including the Roman Empire and ancient Greece, and they often feature unique designs and symbols that represent the issuing authority. Today, gold coins are popular among collectors and investors due to their intrinsic value and historical significance. They are typically measured in troy ounces and can vary in purity, with many modern coins containing 1 ounce of gold. Examples include the American Gold Eagle and the Canadian Gold Maple Leaf.