Posted 03/17/2014 7:03 pm
Those are radial die flow lines, a sign of extreme die wear. Every time a coin is struck, the expansion of the planchet in the coining chamber wears microscopic grooves into the die. These tiny flow lines are initially responsible for the cartwheel luster you see on a nice uncirculated coin. As more coins are struck, the die flow lines become more pronounced until you see a radiating pattern of rough grooves, such as on your coin, with the grooves most pronounced towards the rim.
Extreme die wear--that's one of the more dramatic examples I've seen!
