1939 Mercury Dime — Possible Struck-Through / Retained Die Break
Found this 1939 Mercury dime while going through a silver lot and noticed a really unusual raised area covering most of Liberty’s face/forehead.
At first I assumed environmental damage or corrosion, but after taking macro and side-angle photos, the metal flow and surface texture look more integrated into the strike than I expected. The area appears raised rather than sunken, and the rim/reeding still look normal.
A few people suggested:
struck-through retained debris
heavy grease strike / filled die
retained die break or late-stage die deterioration
I haven’t been able to find another documented 1939 Mercury dime with this exact appearance.
Not claiming anything definitive — just trying to determine whether this is:
a legitimate mint error
or
post-mint damage that happens to mimic one
Would appreciate opinions from error specialists or Mercury dime collectors.