US Coins

5-ounce silver quarter dollar has post-strike finish

This is the sixth and final part of a feature story about finishes used on U.S. coins, which first appeared in the June 6, 2016, Monthly issue of Coin World:

The America the Beautiful 5-ounce .999 fine silver quarter dollars struck at the Philadelphia Mint are issued in two versions — bullion and Uncirculated.

Pricing for the bullion versions is closely aligned with the daily fluctuations in the spot price of silver. The bullion coins are sold through the Mint’s network of authorized purchasers for subsequent resale into the secondary market.

Pricing for the Uncirculated versions is subject to a weekly price adjustment based on the metals price. The Mint sells the Uncirculated coins directly to the public.

When the Uncirculated 5-ounce silver coins were introduced with the 2010-P coins,  the Mint charged $279.95 per coin. Because silver prices have dropped significantly since then, the 2016-P issues and others still on the Mint’s product catalog are offered at $149.95 each.

On the secondary market, examples of either finish will cost more if graded and encapsulated by a major third-party grading service.

The bullion coins are struck on 3-inch planchets in the condition the Mint receives them from their vendor, Sunshine Minting in Coeur d’Alene, Idaho. There is no special treatment of the dies, planchets or the finished coins for the bullion version.

When the Uncirculated version first exits a dedicated coinage press after striking, it looks little different from a bullion strike, except that the obverse bears a P Mint mark in the field to the right of George Washington’s portrait.

The Uncirculated coins then receive a post-strike finish, a vapor-blasting, as explained by U.S. Mint spokesman Michael White.

“The machine uses a water vapor and ceramic media mix,” according to White. “It is similar to sand blasting, but instead of using dry compressed air [propelled at high speed], it uses a compressed wet vapor. The finish is applied to the coin after striking and not to the die. This will provide a consistent coin-to-coin finish.” 

Before striking, the ready-to-strike planchets for both versions often exhibit prooflike surfaces.

Before the Mint received and implemented the specially designed automated vapor-blasting equipment for the collector version, existing equipment employed for 3-inch medal finishing had to be retrofitted for finishing the Uncirculated silver coins. The result from the retrofitted equipment was inconsistent application of the finish — the grading services noted various submissions of Uncirculated 5-ounce silver coins having incomplete or different levels of the Uncirculated finish.

As technology advances and the U.S. Mint’s skill sets advance, it’s a sure bet that the number of finishes the U.S. Mint can impart on a coin will not remain static.

It will be interesting to see what the U.S. Mint comes up with next.

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