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Components of Grading Mint State Coins (Con't)

By Rob Lehmann

Quite often, first year type coins are extremely well struck. Examples that come to mind are 1892 Barber coinage, 1878 Morgan Dollars and 1948 Franklin Halves. It’s almost as if the U.S. Mint is proud of their product when it comes out of the gate, and puts forth an extra effort in the production process. This is just a hypothesis and would warrant further study to prove conclusive. But, the truth is this. Lousy strikes result from either poorly engraved dies, worn out dies or inadequate striking pressure, all of which are controlled at and by the United States Mint.

Luster

Where strike may be the most value-related component of grading, I would submit that luster is the most technical-related aspect. In other words, professional and amateur graders alike place more of an emphasis on the luster of a mint state coin in ascertaining its grade than either strike or surface preservation. I’m going to go out on a limb on this one and say that luster will comprise 30-50% of the overall grade of a coin, and a dull coin could NEVER (under any circumstances) be considered a GEM.

How does luster occur? Luster is the byproduct of light reflecting off of flow lines. Flow lines are the microscopic, symmetrical lines that are caused when the die strikes the planchet of the coin under pressure. These little raised lines result when the planchet’s metal flows outward from the central pressure of the die. As light comes in contact with these flow lines, it literally dances off of the surface of the coin giving us an effect that we call luster. When the die is heavily polished, this effect can be intensified. The polish transfers to the flow lines making them even more reflective and the luster more pronounced. Most new dies are heavily polished. Keep in mind, newer dies have little or no wear. Consequently, a new, polished die with no wear is much more likely to produce a GEM quality coin than an older die with little or no polish evident.

Since the highest points of a coin are these microscopic flow lines, they are also the areas that wear first. Luster will discolor or burn long before any wear is evident to the actual design elements. This is precisely why most graders place such an emphasis on a coin’s luster. Luster is directly correlated to the coin’s originality or “freshness”, and hence is the single most influential component in assigning a technical grade.

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