1997 D Nickel Mint Mark

COOP, I am an old man and absolutely mean no disrespect and understand your statements. I have spent a long life as a mathematician and engineer and have enjoyed numismatics for the better part of my 75 years. The flow lines are radiating from the center of the coin in 180 degrees. I can't take extreme fine detail photos, but I assure you that every other device on the obverse of this coin are from a strong strike and are clear with no signs of MD or deterioration. It of course shows circulation use, but even that is not extreme. I'm just saying that I have never seen Die Deterioration that caused a problem with only the mint mark and all other devices remain strong. The mint workers did not place the original mint mark on the die, but were they allowed to do any maintenance to the dies? Two coins that show the same mint mark damage simply causes me to wonder.

COOP, I understand and appreciate your time here regarding this coin. I do have one last observation. looking at the bottom right photo; if all you cold see was the mint mark and you had no date information, and saw the split serif what would your first thought be? Thanks for your comments and education efforts. Randy