Sorry but can't help but notice how amazing the pics are for the close ups. What kind of microscope do you use?
It's a generic one I got from Amazon for about $60 a few years back. I don't know if they still sell it, but it looks like this. 5MP pictures. Up to 300x, but it's not needed so a variable zoom is best. A lamp to the side and a small angular block to get a different look.
Or possibly a die gouge. Occurs when they are working on a die and the tool slips, leaving a gouge/mark. Probably not a big deal either way