Among regular circulation strikes, Morgan Dollars found with deep mirror proof-like (DMPL) or proof-like (PL) surfaces are a particular point of interest for many collectors (Buy on eBay). Although such coins sometimes occur within other series, they are most frequently noted, collected, and studied for Morgan Dollars. The reflective or mirror-like surfaces make these coins immediately noticeable and among the most beautiful circulation strike examples of the series.
The creation of DMPL and PL Morgan Dollars was the result of the manufacturing process for the individual dies used to strike the coins. In the typical fashion, the dies were created from a master hub with all of the major design elements transferred to the die. As a finishing step, the dies were basined within a zinc receptacle containing water and slowly revolving finely ground particles. Depending on the amount of time the die was basined, a proof-like or even deep mirror proof-like die could be produced.
When freshly basined dies went into production, a limited number of struck coins would have deep mirror proof-like or proof-like surfaces. As production with the dies continued, the reflectivity of the fields would wear down, creating coins with more typical surfaces. On some occasions, dies which had been in production would have the fields basined again, creating more proof-like coins. However, these tended to have less contrast between the fields and devices compared to the earlier coins struck with the originally basined die.
Determining if a coin is proof-like or deep mirror proof-like can be difficult for even the most experienced collectors. The most reliable way is to hold the coin on a printed surface to determine how many lines of print can be seen clearly reflected on the coin. A proof-like coin should have a minimum of 2-4 inches of print clearly visible, while for a coin to be deep mirror proof-like it should have as many as 6-8 inches of print visible. The third-party grading company PCGS uses the designations DMPL or PL on their holders, while NGC uses DPL and PL. In order to receive the designation, both sides of the coin must exhibit the necessary characteristics.
The scarcity of DMPL and PL Morgan Dollars varies throughout the series. There are some issues which are extremely rare with the PL or DMPL designations. The 1884-S Morgan Dollars is the earliest issue with very few PL coins identified and virtually no DMPL coins. There are numerous later issues of the series which are rare with the designations, such as the 1901, 1902, 1902-S, 1903-S, 1904-S, and all of the 1921 issues.