Only 2 proof 1975 Roosevelt Dimes lacking the S mint mark were discovered in mint sets. This variety is immensely valuable.
Being proofs, these coins have a flawless mirror-like cameo finish made using specialized dies and planchets.
Each of these two coins is professionally graded and valued at over $550,000 given their rarity.
The two coins were originally found in 1975 S Mint proof sets before their error was noticed.
Lacking the S Mint mark which should be found below the date makes them extremely rare.
The prestige and value has been verified by top coin grading companies like PCGS.
These are crown jewels for many advanced Roosevelt Dime collectors and in huge demand.