1975 No S Proof Roosevelt Dime

The 1975 No S proof Roosevelt dime is widely regarded as one of the most famous and valuable errors in modern US coinage. A die intended for proof production at the San Francisco Mint was mistakenly left without the 'S' mintmark, and a tiny number of dimes were struck from it and slipped into proof sets sold to the public.

Unlike most collectible errors, which can number in the hundreds or thousands, this variety is known from only a couple of confirmed examples, placing it in the same rarefied company as legendary American rarities despite being a 20th-century coin.

Starting in 1968, proof coins for US Mint proof sets were struck at the San Francisco Mint and marked with an 'S' mintmark to distinguish them from circulation strikes. Occasionally a working die was prepared without the mintmark being punched in, and if not caught, coins struck from that die entered proof sets undetected.

The 1975 error is the rarest of several 'No S' proof dime varieties found across the 1968 to 1975 period, with the shortage of known survivors suggesting the flawed die was used only briefly before being identified and pulled or otherwise limited in its output.

The coin matches a standard 1975-S proof Roosevelt dime in every way except for the missing mintmark: Roosevelt's portrait on the obverse and the torch-and-branches reverse are struck to proof standards with mirrored fields and frosted devices, but the mintmark area on the reverse, where an 'S' should appear to the left of the torch, is blank.

Because of its extreme rarity and value, any claimed example must be verified by a leading third-party grading service; the coin should still be housed inside its original proof set packaging or accompanied by strong provenance when possible, as this variety is a prime target for deceptive alterations.

With only a small number of genuine examples confirmed to exist, the 1975 No S dime has sold at auction for hundreds of thousands of dollars, making it one of the most valuable coins of the entire 20th century relative to its face value and age. Prices realized have varied by sale and condition but consistently rank among the highest for any modern US error coin.

Given the extraordinary value and the associated forgery risk, authentication by a major grading service is essential, and unverified claims of an example should be treated with strong skepticism.