The dime was the first coin made by the U.S. Mint, even before any Mint building existed. George Washington ordered the first run of dimes in 1792, which were made on a borrowed press kept in the owner’s basement.
The first dime produced in a U.S. Mint building was struck in 1796. The earliest 10-cent coins pictured Lady Liberty, either in bust or full profile form. From 1916 to 1945, designers put wings on Liberty’s head, leading people to mistake her for Mercury. (Today, these dimes are referred to as Mercury Dimes.) President Roosevelt’s image first appeared on the dime in 1946.
Traditionally, dimes were predominately silver, though some early ones were made of copper due to a silver shortage. The Coinage Act of 1965 removed all silver, replacing it with a combination of copper and nickel.
Like other coins, the most valuable dimes survive the years in mint condition. This does not mean the coin appears as it did when it was minted. Changes in coloration are normal and even expected. Cleaning a coin may detract from its value. The dimes that command the most value are in excellent condition and rare, due to various reasons, including production errors, small quantities produced or large quantities melted for their silver content.
Two organizations certify coins, the Professional Coin Grading Service (PCGS) and the Numismatic Guaranty Corporation (NGC). Both use the Sheldon Scale to assign a numerical rating, from 1 to 70. Coins rated 60 or higher are also referred to as "mint" state coins and are considered the most valuable.
These are the 20 most valuable dimes, and they are worth a combined $6.1 million.