Collectible coins encompass various categories, including historical, commemorative, and error coins. In the United States, the $20 gold coin, often referred to as the double eagle, is a notable example of a high-value collectible. Patterns and die trials refer to experimental coins made by mints to test designs or technology before mass production. These pieces are typically produced in small quantities and are highly sought after by collectors due to their rarity and unique attributes.

Item Denomination Series Year Mint
1861/52 $20 Clark, Gruber & Co. $20 (Twenty Dollars) Patterns & Die Trials 1861 Denver, Colorado