Collector Found Rare Mint Error in 2004 Proof Set
A 2004-S Proof Roosevelt dime with a 25% obverse indent was discovered inside an original sealed U.S. Mint set.
Updated on Sept. 27, 2026 in Collecting
Live Poll
Do you trust products sold in sealed original packaging more than those that have been opened?
A collector recently identified a rare error coin, specifically a 2004-S Proof Roosevelt dime featuring a 25% obverse indent, housed within its original government-sealed Proof Set. The set remained sealed for 22 years before the anomaly was identified at the 2026 ANA World's Fair of Money.
Why it matters
The discovery is significant because the coin remained protected within its original six-coin plastic lens for over two decades, confirming the error occurred at the San Francisco Mint during the initial 2004 production run.
The error coin weighs 2.268 grams and displays a 25% obverse indent caused by a second planchet overlapping during the strike. The entire set was originally issued by the U.S. Mint on June 3, 2004, for a price of $22.95.
The players
San Francisco Mint
This facility is one of the primary production centers for the United States Mint and is responsible for manufacturing proof coinage.
American Numismatic Association
This is a non-profit organization dedicated to the study and collection of coins and currency, which hosts the annual World's Fair of Money convention.
The details
The error occurred when two planchets entered the San Francisco Mint coining chamber simultaneously, causing one to partially obstruct the other. Because the U.S. Mint seals these annual sets in rigid plastic lenses before distribution, the coin remained preserved in its original state for 22 years until its recent discovery in Pittsburgh.
Timeline
The U.S. Mint released the 2004-S Proof set on June 3, 2004.
The ANA World's Fair of Money occurred in Pittsburgh from August 25-29, 2026.
Roadmap
The discovery reflects a broader trend where collectors prioritize error coins that remain untouched in original government packaging over loose currency. This market shift values the preservation of the physical lens as much as the rare minting flaw itself.
Collectors should inspect their own legacy Proof Sets for similar indentations, as manufacturing errors can sometimes hide in plain sight for years. Professional evaluation is recommended if a unique striking error is suspected inside a sealed lens.
The takeaway
Collectors should carefully review older proof sets for subtle minting errors that may have bypassed initial quality control checks at the mint. These rare finds demonstrate that even mass-produced government sets can occasionally contain unique numismatic anomalies.
Further reading
Learn more about the market for rare coins and error discovery at the Collecting section.
Source note: This article includes information reported by CoinWeek.
Live Poll
Do you trust products sold in sealed original packaging more than those that have been opened?
