Collectible coins can be classified into various types, including patterns and trial coins, which are experimental pieces created to test designs or minting processes. The United States has produced a notable Three Dollar gold coin, which was minted from 1854 to 1889 and is a popular target among collectors. Patterns are often unique and not released for general circulation, while trial coins serve as prototypes for potential future designs. Both categories are highly sought after due to their historical significance and rarity.

Item Denomination Series Year Mint
United States of America 1866 N/A Patterns & Trial Coins $3 $3 (Three Dollars) Patterns & Trial Coins 1866 N/A
United States of America 1866 Philadelphia Patterns & Trial Coins $3 $3 (Three Dollars) Patterns & Trial Coins 1866 Philadelphia
United States of America 1874 Philadelphia Patterns & Trial Coins $3 $3 (Three Dollars) Patterns & Trial Coins 1874 Philadelphia