Collectible coins, particularly U.S. coins, are often categorized by their historical significance, rarity, and demand among collectors. The 1872 Pattern coins are a notable subset, as they were experimental pieces created to test new designs and are not intended for general circulation. Specifically, the "P" denotes a striking from the Philadelphia Mint, and these patterns are highly valued for their rarity and unique designs, often representing transitional phases in American coinage. The 1872 patterns showcase the innovative spirit of the period and are sought after by numismatists for their artistic and historical importance.