Grading, Luster And Flow Lines

Any well-struck coin will have full luster if unworn and undamaged. Microscopic flow lines will always be present, with the coarser die-erosion lines developing as the die wears throughout its service life.

P.S: excellent photos!

I have thought that luster does have an affect on the grade but mostly on grades of like MS-63 or higher. I may be wrong but would like to hear your comments.

The Royal Australian Mint for some years have been further hardening their dies for circulation coins by nickel plating them, and radial mint luster is either non existent from new dies and almost so from very worn dies, which I suspect have a much longer life and / or are replaced more often.

Whatever the case, radial mint luster these days is just not obvious any more, with current circulation coinage.

As for the old .500 fine silver coinage, which was last struck in 1963, that is quite a different situation. These coins had an alloy of .500 silver, .400 copper, .050 nickel, and .050 zinc. The panchets were acid washed and rinsed before striking and so the surface was less dense. The dies were just heat hardened, and I suspect a longer die life was tolerated. Radial mint luster was very obvious on these coins when new.