Looks like it's probably what's called woodgrain toning. Are the lines raised, incuse or even with the surface?
That coin is scratched to heck. Definitely post mint damage... the musings of a bored elementary school kid, most likely.
Who rubbed sandpaper over that coin? I can see the scratches that have cut into its surface. What a shame.
It looks like it may have something to do with being an improperly mixed alloy (woodgrain), due to the lines being orientated in the same direction. There is a lot of refection in the photos which indicates some cleaning has occurred.
