Proof, DMPL & PL Morgan Dollars
Proof, Deep Mirror Proof Like AND Proof Like coins are commonly referred to as PR, DMPL, PL and in that order. One problem that needs to be explained first is that a DMPL Morgan Dollar is not related in any way with a Proof Morgan Dollar. DMPL Morgans where struck with business dies and intended for circulation, but Proof Morgans where struck with proof dies and intended for collecting and presentations. So, with this fact in mind, let's look at some more facts to clarify this issue.
A Proof Morgan Dollar will not always display a noticeable contrast between the bust and the fields. Although many will, some will attain a satin appearance or toning that takes away from the Deep Mirror appearance and contrasting features. Remember, Proof coins can tone differently and were struck from specially prepared dies called Proof Dies.
These dies are prepared differently than business strike dies, and often are superior in quality than business strike dies. However, there are many PR Morgan's that have weakly struck features. Proof Coins struck from Proof dies must never be confused with coins struck from overly basined business dies that causes a business strike Morgan to display a DMPL appearance. A Deep Mirror Proof Like coin is not a Proof coin, and is no way related when it comes to the dies they were struck with.
Morgan Dollar Working Dies were basined before striking planchets, and in this process the working die was placed in a zinc receptacle full of fine grit. The longer the die was in this receptacle the more mirror finished it became. This resulted in many Morgan Dollars obtaining a DMPL or PL appearance.
Also, a Deep Mirrored coin will display shallow "striations" in the fields from when the metal was stretched or thinned as it was squeezed between the dies. These striations must not impede the reflectivity in the fields for a Morgan to be DMPL, but most were polished off during the basining process so the mirror fields will display greater reflectivity at greater distances. Below is an example of a true Deep Mirror Proof Like Morgan Dollar.
In other words, a Proof Morgan Dollar was struck with a specially prepared Proof die, and a DMPL coin was not. With experience the collector will be able to distinguish the different characteristic(s) between the die strikes so as not to confuse a Proof with a DMPL coin. However, PR Morgan Dollars are rare, so the main point is distinguishing between coins with "normal" and striated fields and deeply reflected mirrored fields.
One method is a white piece of paper and a small ruler. Place the ruler on a white piece of paper, use cotton gloves to hold the coin at a slight angle, and if you can clearly see at least the 6 inch mark clearly on the ruler, without distortion, then the coin is possibly a DMPL coin, but should at least be Proof Like. This does not apply to coins that have been polished by a dealer or ebay seller. Viewing the coin under a 10x loupe or microscope will determine if a coin has been doctored, but it might not be readily apparent to the inexperienced eye, so a submission to a reputable grading service might be in order.
(Note: Not all Morgan Dollar dates were struck as Proof. No Proofs were struck in 1921 except CHAPMAN & ZERBE Proofs and most of these don't have PL surfaces and are so rare that to buy a raw "supposed" example would be foolish unless one is an expert on these Proofs. Much debate still remains among experts concerning the Chapman and Zerbe Proofs).
Also, it should be noted, that many Proof coins only obtain a PR label and are not always cameo or deep cameo. As stated above, a Proof is struck from special dies and this is an obvious diagnostic for the trained eye, but it's not always evident in photographs. So don't be fooled by seller's claim that a coin is related to a Proof just because it has Proof like or a cameo appearance.
Below are three examples of Proof Morgan Dollars for the viewer's reference. As you can see the appearance of a true Proof Morgan has a mellow luster and often deeply struck details. Most Morgan Proof mintages are under a thousand coins, or just a little over a thousand, so they are very rare and are not usually found on ebay. If you do find a Proof up for bid on ebay, I suggest not bidding on the coin unless it's attributed by PCGS, NGC, ICG or ANACS.