Collectible coins, often referred to as numismatic coins, encompass a variety of types, including historical pieces, commemoratives, and proof coins, each with distinct characteristics and value. In the United States, collectible coins can include rare denominations like the 15-cent piece, which was minted during specific historical periods but is not commonly found. These coins can be evaluated based on factors such as rarity, condition, demand, and historical significance, impacting their market value significantly. Collectors often seek out these coins not only for their monetary worth but also for their cultural and historical relevance.