G'day, Beautiful coins, all of them.
quote: "... here we call it "bag wear", and it doesn't necessarily kick an MS coin out of that range ..."
- I'm more familiar with the term "bag marks". Because such marks arise during processing at the mint, &/or during transport after that, they do not count as evidence of "circulation".
Bag marks are typically found in relatively protected parts of the fields, as one might expect when the damage arises from one coin falling, edge first, onto another. Or from abrasion within bags. Rim dings are a difficulty, because they might arise either in the Mint, or in circulation; but we cannot attribute them, either way.
A coin may exhibit bag marks AND signs of wear from circulation. But then it is no longer "Unc".
Although a coin with bag marks may be regarded as "Unc", coins with few or no bag marks deserve even higher grades, of course.
quote: "... so does it matter where the coins picked up those marks?"
- I think the answer must be "yes", for the reasons given above.
And Kurt has distinguished between this sort of mark, on one hand, and the wear to high points, which is regarded as evidence of circulation.
Of course, lustre, etc, are also factors to be considered.
In 1860, the U.K. switched from copper to bronze for its lower denominations.
Bronze is harder, and less chemically reactive.
The new bronze pennies were half the weight of the previous copper pennies.
I would have expected bag marks to be more of a factor with copper coins than with bronze.
In my experience, bag marks are most often discussed in the context of gold coins. This might be because gold is softer, and denser, than other metals in mumismatic use. But, perhaps another factor is that grading is at its greatest abstraction in gold coins, because of their high intrinsic value.
I haven't seen much discussion of bag marks in relation to modern CuNi, which perhaps supports my previous observation.
My own perspective is that I collect coins for their history and their art. They were manufactured in order to be circulated, so I don't begrudge dings or signs of wear; although I agree that fewer dings and less wear is more desirable. Grading, on the other hand, is what happens when accountants take up investing in coins as a commodity.
Peter in Oz