Featured Luster: A guide for Beginners

Excellent write up, but I disagree with the part I quoted above, in particular the bold portion. It simply is not true. Yes, after a certain number of coins have been struck by a die, the die will show signs of wear. This wear can often appear as deepened lines in the surface of the die and yes these are called flow lines. But these deepened lines are not what creates or causes luster.

The confusing part of this is that there are 2 different kinds of flow lines. And by using the same term to describe both, people often make the same mistake you are making. These are the two different things - flow lines in the metal planchet itself - and flow lines in the surface of the die caused by the repeated flowing of that metal across the surface of the die - or wear.

Perhaps the easiest way to understand this difference is this. When a coin planchet is just sitting there waiting to be struck, the metal in that planchet is fixed in place, it is 100% solid and does not move. But when the planchet is struck, the metal does move - it flows almost like a liquid. But it is the stiffest and thickest liquid you can imagine. And it only moves because of the extreme pressure being forced upon it by the dies. You can think of flow lines as being the tracks left by the upper part of the metal as it moves across the lower parts of the metal. Now it is this movement of the metal itself, the flowing of the metal, that creates luster. And it has absolutely nothing to do with wear on the die.

And when a die becomes worn and begins to show flow lines, the flow lines in the die will be higher and more distinct than the flow lines of the metal itself. They will appear as higher ridges and in fact be much like one the devices on the coin - a depression to be filled in by the flowing metal, only on a much smaller scale.

And coins struck with a worn die will never, ever, have better luster than a coin struck with a new die. Again, this is confusing for a very good reason.

1 - the very first coins struck with completely unused dies are typically not very good examples. This is because the once the dies are keyed into the press they have to "settle" if you will. And quite often the spacing is then adjusted after just the first few coins are struck. These first struck coins are typically discarded and placed into the scrap pile for reprocessing. But once settled, the dies produce their very best coins, the coins with the very best luster and most complete details. These are the coins that are trully considered to be first strikes and they are struck with new dies.

And that's the confusing part, because people will read this explanation in a book than think that only used dies produce the best coins. Well yes, the dies are used, on perhaps as few as 3 or maybe even a dozen coins while the settling and adjustments are made. But the dies do not receive any wear from this tiny number of coins. There are no flow lines in the surface of the die yet. These dies are still new. But people tend to misinterpret the explanation.

And your last sentence, Proof Like coins do have cartwheel luster. Even Proof coins have cartwheel luster. But that luster has a different look, but it is not because there is little or no wear on the die.

Proof coins have the look they do because of two things - the planchets are highly polished and the dies are highly polished. Today's Proofs are even different than the Proofs of old for modern Proof dies are chrome plated to add an even smoother and more polished surface, and to make them last longer. While the Proofs of old did not have this chrome plating and on them the cartwheel luster is more evident.

By contrast, the surface of business strike dies are not polished as much and the planchets are not polished at all. And Prooflike coins come about as a result of new dies being used on an exceptional, but ordinary, planchet. For whatever reason, this particular planchet has a smoother surface than normal planchets.

As I have explained many times before, if you think of luster as looking like this - /\/\/\/\/\/\/\/\ - it then becomes easier to understand. And different types of luster caused depending on the height of those lines. This explains the difference is luster on all our coins. Like the difference in luster on Peace and a Morgan. A Jeff and a Liberty; a Walker and a Frankie. A business strike and a Proof. Luster is luster, and no matter what the particular look it may have, in every single case it is always caused by the very same thing - the actual flowing of the metal in the planchet, nothing else.

 

I would agree about quality of strike, but quality of luster is arguably the single most important factor in modern market grading.

 

I understand what you are asking, and it is a trap that too many fall into when trying to explain or understand luster and what creates it. However, there is strategic point that is undeniable and completely disproves the theory of wear on the die being the cause of luster. It is a simple thing, and because it is so simple it is often overlooked. It is what I said earlier - coins struck with new dies have amazing luster, and yet these dies have no wear lines etched into them. So if wear on the die was the cause - this would not be possible.

But there are several possible reasons for the variation in quality of luster. And for the purposes of this discussion I am making the assumption that all coins being discussed are Mint State.

First of all one must realize that when comparing luster on any 2 given coins that you have to remember that you are only looking at these coins as they are now in the present time. And the way they look now, today, is almost certainly not the way they looked when they were freshly minted.

So, to answer your question all one has to do is consider what things there are that can cause the quality of luster on any given coin to diminish or change. These things are all well known but seldom considered when these discussions arise. Quality of luster can be changed by the following -

1 - Toning, we all know that toning can mute luster in its early and intermediate stages. Later, as the toning progresses and eventually turns into corrosion, luster can even be totally destroyed.

2 - Dipping, again it is undisputed that dipping a coin reduces the quality of luster on any coin. True, a properly dipped coin retains much of its original luster, but some of it is undeniably taken away by the acid in the dip solution.

3 - Handling, many things are covered by this single term for the purpose of my comments - handling at the mint as the coins fall into the hopper and are later transferred into bags; friction imparted to the coin in the mint bags and during the transport of these bags, roll friction, cabinet friction, and friction imparted to the coins in actual circulation.

Now these are all things that happen to a coin after it is minted. But let us not forget that there are also things that change during the life of a coin die, and all of these things have a direct impact on the quality of luster that any given coin has.

During the course of a die's life the pressure being used to strike coins may change for as the dies wear the pressure may be turned up slightly in an effort to achieve fully struck coins.

The spacing of the dies may also change minutely during life of the dies. This may be intentional or completely unintentional, for as the presses run through their cycle things move, spacing changes, and the dies are adjusted.

Die polishing, as we all know dies were routinely removed from the presses after a period of use, polished and then used again. This polishing affects the quality of luster greatly. And the simple fact that the dies were removed from the presses and then re-inserted for additional use changes everything in regard to the quality of luster imparted to the coins. For the pressure setting may not be exactly the same, the spacing is bound to be different, in fact has to be different. For as the dies wear and/or are polished the spacing between them has to change because of the loss of surface metal. This may be a minute measurement, but it is absolutely a change. And any change in die spacing is going to have an effect on the quality of luster imparted to the coins.

But keep in mind, I am most definitely not saying that wear on a die has no effect on luster, it most certainly does. But wear on a die is not the cause of luster. Metal flow is.

To prove this to yourself all one has to do is think of one thing - the highest graded coins there are. I am talking about coins that have completely full details; coins that are relatively, if not completely, mark free; coins that have booming luster that jumps out at you; coins that have a semi-Proof Like surface; in almost every case these are EDS coins, coins struck with dies that have no wear and show no sign of die deterioration.

 

It is not irregularities that create the cartwheel effect of luster, quite the contrary, it is the regularity of the metal flow lines that create it. Again, think of this simple illustration as being what the metal flow lines look like - /\/\/\/\/\/\

Now if those metal flow lines were not all the same size the refection of light would be distorted and disturbed and there would be no cartwheel effect. Instead the refelction would be broken up and blurry, just like the surface of a mirror would be if the glass were uneven.

It is precisely this uneven surface which reflects light in every direction and which we see as luster.

 

Yes, he is.