Coins struck on experimental planchets provide a fascinating window into the U.S. Mint’s occasional forays into alternative metal compositions. Famous recent examples include 1974-dated Lincoln cents struck on aluminum and bronze-clad steel planchets.
Closer to the present we have, according to error dealer Mike Byers, an estimated 20 State quarter dollars, six to seven Anthony dollars, and one Sacagawea dollar struck on experimental planchets. But unlike the 1974 cents, there is lingering uncertainty over whether the strikes or the planchets were authorized by Mint authorities. Let’s focus on the quarter dollars, where sample size and diversity of appearance is greatest.
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Every State quarter dollar design from 1999 is represented (Delaware, Pennsylvania, Connecticut, Georgia, and New Jersey) along with a 2000-P Massachusetts quarter (the first quarter struck that year).
The coins weigh between 5.9 and 6.3 grams, with some planchets composed of a solid alloy and others consisting of cladding over a copper core. Chemical analysis of four coins reveals surface compositions of 69 to 77 percent copper, 20 to 27 percent zinc, 1.6 to 2.9 percent nickel, and less than 0.1 to 2.6 percent manganese. There is every reason to believe that these planchets were punched out of experimental stock used in the testing phase for the clad-composition Sacagawea dollar, which was introduced in 2000 and whose surface composition is 77 percent copper, 12 percent zinc, 7 percent manganese, and 4 percent nickel.
The quality of the strikes, the quality of the planchets, and the timing of production are all at odds with what we know of past experimental strikes. The well-struck, proof-like 1974 aluminum cents reflect the care that is typically taken in the production of experimental coins. There is no point in testing the physical properties of a planchet unless its specifications are exact. And there’s no point in assessing the qualities of a strike unless the press settings are ideal. But what we find in these experimental quarter dollars is far from ideal.
The edges of the quarter dollars are rough (sometimes exceedingly so), suggesting the blanks were crudely punched out of the strip. The perimeter of many of these coins is also rough. At least one planchet was severely scratched on its obverse face before striking. Since any edge roughness should be smoothed out during upsetting, it’s likely that some of these blanks were never upset or were too small to preserve evidence of their passage through the quarter dollar upset mill. Some of the coins show incomplete reeding and metal flow in peripheral letters, both signs that the blanks or planchets were undersized relative to the diameter of a quarter dollar collar.
If you’re testing the effects of design and striking pressure on experimental material, you are not going to use undersized, damaged planchets. You will also be careful about press settings and operation. But some of these coins show finning of the rim (a sign of excessive striking pressure), while one is broadstruck.
The composition of the Sacagawea dollar was finalized well in advance of the first “VIP” strikes, which occurred on Nov. 18, 1999. But, based on the evidence of a 2000-P Massachusetts quarter struck on a nonstandard planchet, experimental strikes appeared to have continued into early 2000. There is no obvious reason why experimentation should have stretched through all of 1999 and into the following year.
It’s never been confirmed that these coins are the result of authorized testing. All the Mint would say is that they “conducted engineering and metallurgical tests as part of its development of an alloy for the Golden dollar” and that the Mint “maintains no records” pertaining to “test strikes on experimental alloys using current quarter or Susan B. Anthony dollar dies during 1998 and 1999.”