I guess it's not the strike doubling on the M! some flaky reddish matter on the surface of the coin. Barbecue potato chip crumbs? Putty?
I believe this residue would be most closely referred to as "patina" or "verdigris"...or it is indeed BBQ potato chip dust as mentioned above. ;-)
It looks like some kind of encrustation or deposit. Can't really determine the color of it since the entire photo is not color accurate. But it's a Roosevelt dime so the coin is either silver or clad. I'm guessing, if silver, the material is a silver sulfate or some other non-standard silver compound. If clad, then I'm guessing it's some kind of copper extrusion through the clad outer layer.
Slight clash mark from the back of Roosevelt's neck between the branches along with die polishing probably intended to eliminate the clash mark.
Looks like it's been dashed with a bit of red pepper.......that better not be the answer........(devil)
More like the rest of the nail polish was removed. People used to put mail polish on coins they thought had silver in them so they wouldn’t spend them.
the unusual thing I see in this image is the over use of a magnifying glass or microscope to try and find an error coin
Thanks for your expert opinion! A jeweler puts 5 GIA graded "flawless" diamonds in front of you for exactly the same price. On the tabe there are several hand lenses (5X, 7X, 10X, 16X, and 20X) and a Jewler's stereo microscope that goes up to 80X. Which of these "tools" would you pick to examine the diamonds so you get the best one? .
So where does the magnification increase end? Based on your contrived scenario there is no upper limit for which magnification you'd use if there was a plethora of choices in front of you.