Collectible coins, particularly from the United States, can be categorized into various types based on factors such as denomination, minting location, year of production, and special features. A 2012 Denver mint coin, for example, would bear the 'D' mint mark indicating it was produced in Denver. Rolls of coins, such as "1 Roll" of a specific denomination (e.g., dollars), are often sought after by collectors for their potential numismatic value and as an investment. Collectible coins can represent historical significance, rarity, and varying conditions that influence their market value.