Harlan Berk is very knowledgeable, I cannot imagine him ever making such a comment as it is simply not true. You must have misunderstood or misread something.
I knew I read it. From - A Guide to Grading Coins - by Harlan J. Berk "....A "Mint State" (MS) coin is as it was when it fell from the die. It can be ill-struck or even double-struck, but it must have unbroken luster. Less than unbroken luster should not be called Mint State or uncirculated. Uncirculated is actually a misnomer; it does not mean the coin never circulated, but that it has unbroken luster and no wear other than die wear. Knowing the difference between die wear and real wear is tricky but unbroken luster is the faultless test. "
I stand corrected. Nonetheless - it's still not true. Based on that definition 99.99% of all coins would be defined as circulated or not Mint State. Including those found in the hopper at the mint as they come off the coin presses. A break in luster is just that - a break in the luster. What's a bag mark if not a break in the luster ? What are the marks on Liberty's cheek on Morgan dollars if not a break in the luster ? The same is true of any coin. Mr. Berk has made a very poor choice in his wording in his effort to describe a coin that is found in circulation that may still be classified as uncirculated. Just as an example, here is a coin from Mr. Berk's site that he is offering for sale that he has graded as MS64. CLICK HERE Take a look at the pic and click on the Larger Images - would you say that coin has no breaks in luster ?
I didn't like the luster comments, but things like this that come from people who know a thousand times more about collecting than I do are confusing. I'll follow your advice on the definition of uncirculated. Thanks.
I gotta tell ya Cloud - you sure surprised the heck outta me with that quote from Berk. With comments like that it's no wonder so many collectors are confused I understand what Mr. Berk was trying to say - but he did a poor job of saying it. What he should have said was that signs of wear will appear as a break in luster. And then gone on to explain that there are other causes for breaks in luster besides wear.
Silver, regardless of whether it's a bar, or a coin, will tarnish. It's a natural process that occurs when the silver comes in contact with any material that has hydrogen sulfide present in it. As far as tarnish, or toning, de-valuing coins, is not entirely correct. In many cases, a nicely, attractively toned coin can have an added premium to the value because of the toning. How much premium is all in what someone would really want to pay.