Collectible coins encompass a variety of types, including historic, commemorative, and error coins. The 1873 Shield Nickel, part of the circulated coinage in the United States, features a shield design representing unity and strength. The three-dollar gold coin, although less common, was minted to cater to the changing economy and is sought after by collectors. Coins from the United States of America often carry significant numismatic value based on rarity, condition, and historical context.