What 'Cartwheel' Looks Like In Higher-Grade IHCs

I thought it would be educational to discuss the difference between 'cartwheel' seen on higher grade IHCs, and bright surfaces seen on altered coins, ie dipped, whizzed, or polished.

Cartwheel describes a distinctive quality of surface reflection seen on coins with remaining mint luster. The cause is metal flow acting on the surface of the die, creating microscopic grooves positioned radially from the center towards the die's edge. The visible result on a struck coin are noticeable directional reflections, as seen clearly below on a MS-grade IHC.



To a lesser degree, cartwheel is present on AU coins and even sometimes XF45 examples in protected areas. But what's the difference between original mint surface cartwheel, and the brightness associated with dipping or polishing a (once) brown IHC? When chemicals or tools are used on a bronze coin, the minute, outer surface of the coin is removed. With cartwheel removed, the coin may look bright, but the distinctive directional reflections just aren't there. Compare below an original AU coin, still showing cartwheel--to a bright "AU details" coin which exhibits none of the reflective quality associated with mint surfaces.