A mirror surface, or prooflike Morgan Dollar, is defined as having a reflective surface of between 2 to 4 inches, a deep prooflike as 4+ inches. To determine this, set the coin on its edge on a printed page, if you can see the words clearly at least 2 inches in, it is pl, 4 or more, deep mirror. A semi-pl will have some pl quality but does not warrant a full pl designation, and there are some that are pl on one side only. This affect would wear of the dies after about the first 10% of coins struck, and since some mints used dies longer than others, this accounts for the disparate relative scarcity between them. There are also coins which are brilliant with a uniform appearance, and then some are cameo, which have a contrast between the devices and the field, like a cameo in a pendant, and these are considered the most desirable.
This popular subset of the Morgan dollar series had its first start in the early to mid ’60s. They started as a novel item and the premiums were minimal, the Redbook actually had the admonition “beware early strike Philadelphia issues offered as proof”. Beginning in the 1970’s researchers published books with chapters devoted to the subject of prooflike dollars and their relative scarcity and by the end of the decade their popularity grew. The main source of the wholesale coin market pricing added the prooflike category to their weekly publication in 1979. When third party grading started in the late ’70s, these organizations would assign a numerical grade without a designation. In the late 1980’s the designations prooflike and deep mirror prooflike were added the Morgan dollars certified by these organizations and some started to publish population reports which gave the hobby empirical information as to the true scarcity of these coins and the popularity increased greatly, especially those categorized dmpl to where today their prices are multiples of their regular mint state counterparts.
