1974 Proof quarter with odd markings

[N-7353]

Hey all,
I came across two 1974 proof quarters that have an almost shattered glass like raised markings in the field of the coins. I have posted on other forums and have stumped everyone on those, so I am trying here.
Background: I bought a sealed box of 5 1974 proof sets. Two of the sets have quarters that have these interesting cracks in the fields of the obverse. I do not see any markings in the relief. Since the markings are identical on two coins, it means it is a die error and not planchet. Some of the possibilities that have been thrown out there are crazed die, chrome layer of die cracked or not polishing dies prior to being used. However, no one has a definitive answer.
So now I am here asking the same question. Is anyone able to identify this error?

Larger images can be viewed https://www.dropbox.com/scl/fo/pivbe...=3b0r4dml&dl=0

[MintErrors]

In my opinion, It might be die crazing.

https://www.error-ref.com/die-crazing/

They look more like cracks than an abraded die which is die scratches.
Die crazing to me is light superficial cracks. If they were more obvious under less magnification, collectors might be interested in them.

If you look over both coins you might be able to see common markers on both of yhe coins, i the same location. For example, finding a spider style crack located below the president's chin.

I will say this, even though you probably checked just make sure the cases aren't scratched up and showing up on the proof fields. It's something people should check, you never know if some beginner come in reads the post and wouldn't have thought about the possibility.

With the mint, there are some things that are difficult to assess. The working dies used for proof coins tend to have a low number of strikes compared to a business strike. You can research the number of proof sets made for that year.

The business strike quarters used to strike close ot 325,000 coins per die before being retired from service. I think some can go much further but, those were the typical range I seen in over a dozen canceled dies that I bought that had paperwork telling me the number of strikes each die performed. I do not know if the procedure is the same for proof dies compared to business strikes.

Since most proofs coins are typically struck twice it might cut the life expectancy in half, compared to a business strike. Again, I do not know if the proof coin working dies are made differently or have a longer life.

[N-7353]

Thank you for your response. Crazed die (die crazing) was my initial thought on this one. I guess since it is not a common error, it is difficult for people to identify it.
From what I have researched, post 1970-ish the mint changed how the dies were prepared for proof coins. They would add chrome to the field of the die to all it to last longer. Which is why we have deep mirror in all proof coins now. And they last much longer then compared to pre-1970.
and I have made sure it is not a reflection from the case they are in. While they are not strikingly visible, I still plan on sending one in to PCGS for grading and error attribution. Just for my collection.