Looking at this ‘78 quarter I am curious about the mintmark and the “M” in UNUM. The M’s right “leg” appears to be multilayered. One of the photos of the M is upside down to give a different view.
If you are going to use a microscope, learn how to take images directly from the microscope. Taking a PICTURE of the screen is useless - you have double sampling (digitizing) of the image and that creates artifacts. Either of your full-sized pictures of the obverse is good enough - it shows the whole coin and the context of what you are asking about. Next time shoot them where the coin is SQUARE to the camera, not at an angle... the imaging system will have only a small part of the coin truly in focus and the rest blurry. That plus one of the closeups (next time in focus, please) is enough to identify the obverse item as a "die chip" or broken post (remember: The die is inverted, so the hole in the D in the minted coin is a small post on the die - they break off, causing the filled letter). The images of the reverse aren't as good, but you can clearly see a ridge on the M and that makes it damage not a mint error (something hit the coin with enough force to move the metal).
