How on earth does this not come back as details cleaned?

@LukeMarshall said:
Die polish lines?

That was my first thoughts.

I thought it was die polishing?

Looking at PCGS website, not sure if the lines are supposed to be there.... but looks like there is a Proof66 graded that has lines also, but not as prominent.

I believe this was part of a set of the four gold denominations that was sold in an August ANA auction in 2022. They are not die polish lines, the coins in the set were heavily brushed post-mint. However, the set was graded 64-65. I was flabbergasted to see it as the 1937 mirror proofs are very frequently seen by grading services and should be known to never come with heavy die polish lines like that (aside from them being visually obvious as brushing).

For reference, I have likely seen hundreds of the 1937 gold proofs - and thousands of the 1937 mirror proofs in general if I include the silver and base metal denominations, which were produced in the same way.

They should be bought back by the TPG in my opinion.

@LanLord said:
I have to think those lines were scratched into the die not the coin.
If someone scratched the coin like that, the high points would be trashed, yet they are pretty nice.
The field of the coin is the high point of the die, so scratching only that would be easily possible.

Except the lines are also visible on the high points.

Wrong forum.

Odd, try it in the other board

@ChrisH821 said:
There are two different coins being shown here. The OP coin and Rexford coin are not the same, this is going to confuse many people.

The one I posted is the 5 Pound from the same set that the OP coin was in. All four coins were brushed in the same manner, so it doesn’t matter much - I just only have photographs of the 5 Pound. The cert number for that piece is 44604965 (consecutive as you can see).

@UncleDano said:
Die polish marks.

Nope.