US Coins

Why does this State quarter have no copper layer?

Readers Ask column from Oct. 31, 2016, Weekly issue of Coin World:

Please look at this 2007 Montana State quarter dollar that I received in circulation, including the edge. I wonder whether I found a valuable error coin that was struck on the wrong planchet or a defective one since I don’t see evidence of copper on the edge. 

Eleazar Orlando Torres  /  via email

While it turned out the reader did not have a wrong planchet error, the coin he found in circulation is, however, worth more than face value because of its composition.

I first asked the reader if he could send me an image of the George Washington obverse of the coin, since it’s the obverse side of the State quarter dollars that features the Mint mark. Once he did that, it became easier to identify what he had found in circulation. The reader’s coin carries the S Mint mark of the San Francisco Mint. That fact, along with the coin’s finish, indicates that it is a Proof coin. 

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Next, I asked the reader to help me identify the composition since the San Francisco Mint struck Proof quarter dollars in copper-nickel clad and .900 fine silver versions in 2007. Weighing the coin, at 6.25 grams, confirmed his coin is the silver version, which has no copper core. The copper-nickel clad coin’s weight is 5.67 grams.

The quarter dollar denomination in 2007 was struck in copper-nickel clad composition at the Denver and Philadelphia Mints for general circulation and Uncirculated sets, and at the San Francisco Mint for regular Proof sets. The Proof silver quarter dollars were struck at the San Francisco for inclusion in Silver Proof sets. The facility currently also produces clad America the Beautiful quarter dollars in circulation quality, but for numismatic sales, not for circulation.

The last silver quarter dollars struck for circulation are dated 1964. Silver made a return beginning in 1992 for the dime, quarter dollar and half dollar used in the annual Silver Proof sets.

The 6.25-gram silver quarter dollar contains 0.18084 ounce of pure silver. Using a spot price base of $19 an ounce, the melt value for the reader’s Proof 2007-S Montana silver quarter dollar would be approximately $3.44.

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