Can Proof-like Coins still have Cartwheel Luster?

As a matter of fact, I'm going to a late movie.

BTW, you have misunderstood what J.D. wrote. There is NOTHING IN the PCGS Grading Guide By J.D. THAT SAYS ANYTHING about HOW/WHERE a coin's luster comes from. I just read the parts of that book dealing w/luster AGAIN today!

Tomorrow, I'm going to educate you AGAIN (using numerous sources CT members can look up) so all the BS about what causes luster is finally put to rest.

Good Night all!

 

Log in or Sign up to hide this ad.

That'll be a first.

Do you not see the way the winds are blowing here? Cut your losses, and begone while you have any dignity left whatsoever. I wouldn't believe anything you said even if I already knew it to be true.

 

I actually have a PR70 Kennedy that has a little luster. I generally do not like proofs, because I like cartwheel luster, and I was a little surprised to find a new (2014 I think) PR70 coin with a little luster.

 

That's one of the most informed things you have posted in this thread. It's true...you have demonstrated several times that you are not interested in much of anything dealing with facts

 

@Kentucky at the end of this PCGS shows how the assign grades on ms coins based on luster. Do you find this to be true? In other words, if someone learned to define luster in these five choices and used the same as part of learning to assign a grade, is this consistent with what PCGS doe mostly?

 

Yet in
Featured Luster: A guide for Beginners here on CoinTalk, @physics-fan3.14 says in his OP (I have highlighted in blue his remarks that seem to be exactly the opposite of what you are saying)

Can you explain how this can be?

 

Ok, I can see the point he finally agreed with you. Correct me if I'm wrong, but it seems to come with a definition that there are different types of luster, and one type (a course one, perhaps) comes with wear on die, and the other doesn't. Can you clarify how to distinguish the different types other than looking for die wear on a coin to say it must be one and not the other?

 

Usually a proof coin has an unmistakable appearance about it. The blanks are highly polished and are struck under very high pressure. In my own personal collection I have some 1967 Queen Elizabeth II pennies with full mint lustre, but there is a distinct difference between those and proof ones.

 

Yeah, this is where semantics is getting in the way. The trouble is, our hobby is by definition one of precision. The sole difference between a face-value coin and a six-figure error/rarity could be a feature only measurable under high magnification, for instance, like 0.2mm differences in date digit locations.

So we have to balance precision in language against peoples' natural unwillingness (apparently) to employ such precision. If we were talking chemistry instead of coins such precision would be a universally-accepted standard. And I don't get that; we'll argue the difference between MS67 and MS68 all day with everyone on the same page, but the moment we start trying to effect a common definition for a given term, nobody wants to conform. Heck, we argue the definition of "cud" incessantly even though that's a term no less precise than a chemical formula.

"Luster," to me, is solely and purely a function of the surface irregularities of a newly-struck coin. Once it's circulated enough to wear down those irregularities, the shine is no longer something I would use the term "luster" to describe. A sufficiently-worn die doesn't strike "lustrous" coins at all, even though what they *do* strike isn't exactly dull in finish. The whole point of me trying to be so precise is to forestall ultimately time-wasting (although educational) discussions like this one.

This kind of argument really didn't exist in numismatics before the Internet. It's only happening because newer collectors are uninterested in learning the true precision of the hobby, and society as a whole is so much more individualistic these days that people just_don't_grok the efficacy of holding to that precision. How many electrons - and how much time - have we wasted on this one thread?

 

Prooflike, as applied to Canadian coins, means those coins are specially made with polished fields. They aren't true proofs, because they aren't struck twice at higher pressures. There are no criteria for depth of reflectivity, because they were specially prepared. These coins are graded as PL-63 (as opposed to the normal MS or PF).

For coins which were not specially prepared, there must be a minimum amount of reflectivity to count as PL. Your coin, judged on this scale, would appear to be semi-prooflike.

Prooflike coins definitely have luster.

There has been a lot of back and forth in this thread.... I really hope people have learned and benefited from this (sometimes vicious) discourse.

 

No. The planchet does not become liquefied in the coining chamber. This is absolutely false.

Take a look at the melting point chart for silver-copper alloys. At atmospheric pressure, the temperature would have to be 961C. At higher pressures, it would have to be even higher (remember, things are going to liquefy at lower pressures, not higher ones).

 

Yes, the radial lines on the watch face give you an accurate macro-visual of the micro-effect which causes luster. This is actually a pretty good example, and is simple to see/understand.

 

Luster comes from two effects - the movement of metal, as described, and the wear of the die. Over the life of a die, the luster will change. A proof coin early in the die's life will exhibit luster only from the movement of the metal as it is coined. Later in the die's life, there will be luster from the wear of the die as well. The reflective, polished surface of the die is worn off, leaving a diffuse surface (which we see as luster, as described elsewhere in this thread).

 

So the few Pr mercs ive seen in hand are likely late die state proofs?

 

Yes, fresh dies will have a certain character of luster. But even you cannot deny that, over the course of the die's life, the character of the luster will change. This is due to the wear on the die. There are two effects - the movement of metal, and the surface of the die.

An absolutely brand new, first strike die can and will produce cartwheel luster.

I have a degree in rocket science. We did actually study materials and manufacturing as part of our coursework, to better understand how to actually make the rockets. So yeah, this kinda is rocket science.

J. Dannreuther, in the Official Guide to Coin Grading and Counterfeit Detection, 2nd ed., explains it like this:

"Luster is the result of light reflecting from the surface. As a coin is struck, the metal flows into the recesses of the die because of the pressure applied by the coining press. The metal flow is usually in a radial pattern, i.e., outward toward the rim. On some coins, these lines are all but invisible but are still present microscopically. … Mint State luster is categorized in several ways: flat (flow lines are invisible to the unaided eye, as often happens when coins are struck from worn dies), satin (flow lines may be slightly visible but there is little cartwheel effect), frosty (flow lines are usually visible with a cartwheel effect, ranging from slight to heavy), semi-prooflike (light flow lines may be visible but most are not, being replaced by slightly mirrored fields that have a slight cartwheel effect), and prooflike (no flow lines are visible, with the fields now mirror-like, but with virtually no cartwheel effect).”

I disagree with a bit of what he says here. First, I have seen many late state dies which produced strong luster. It is usually "coarser" than your typical early strike coin, but often seems "brighter." Second, proof and prooflike coins absolutely have flow lines visible. Their lines generally appear more "in" the surface of the coin, rather than "on" the surface (if that makes sense). The word I like to use is "chatoyancy." Take a look at a Tiger's Eye gemstone, or similar gem. There is a certain amount of luster "inside" the gem, even though the surface is polished and mirrored.

 

Obviously, not knowing which coins you have seen, I can't say for sure. But, it is likely. You'll see the exact same effect on Washingtons and Franklins of the same era.

 

Here is a better link: https://www.cointalk.com/threads/luster-a-guide-for-beginners.58435/

My agreement with Doug in the linked thread is with the following:

This is also what I'm trying to say in this thread. There are two competing effects which cause luster - flowing metal, and die wear.

Luster will also change significantly with a number of post-mint effects. Doug and I have always agreed on that point. I think, however, we attribute greater significance to different points. And that is fine, as long as we agree on the basics.

 

To return the thread to the original question, "Do Prooflike Coins have Cartwheel luster?", the answer is a resounding "yes." The character, however, is going to be completely different. Let me present Exhibit A, a PCGS 65+ DMPL Morgan. The luster is more evident in my reverse pictures, but it is present on the obverse. Look in the fields, how there are bands of luster. This appears "under" the mirrored surface, but it gives the appearance of a cartwheel (in hand, it moves just like a regular cartwheel). These are solely from the movement of the metal - a DMPL is going to come from a freshly basined die, where there has not been any wear on the surface of the die. This only happens to dies which have been basined (polished) - not all dies are polished before being put into service. A normal die will have a diffuse surface.




Exhibit B, a PL Barber Quarter. Notice, especially at the rims of the obverse and the top of the reverse, the flow lines from the movement of metal. This is what creates luster:




I don't collect Proof coinage, so I don't really have any pictures to post of proof coins. However, the effect is nearly exactly the same.