It does mean environmental damage, but I can't tell from the photo how severe that damage might be.
If a Coin has a significant defect, such as environmental damage, or corrosion, or a bad rim ding, or cleaning, and other factors - the coin no longer receives a number grade.
In this case it is marked as UNC details. Which means it can't be given a numerical assignment. It has not been circulated, thus the UNC.
If you were to see - Scratch, details, extra fine - it would mean there is a significant enough scratch that the coin won't receive a numbered grade, but is in the EF (or XF) range.
If a Coin has a significant defect, such as environmental damage, or corrosion, or a bad rim ding, or cleaning, and other factors - the coin no longer receives a number grade.
In this case it is marked as UNC details. Which means it can't be given a numerical assignment. It has not been circulated, thus the UNC.
If you were to see - Scratch, details, extra fine - it would mean there is a significant enough scratch that the coin won't receive a numbered grade, but is in the EF (or XF) range.






















