An uncertain number of Uncirculated 2010-P Grand Canyon National
Park 5-ounce silver coins missing the post-strike finish were shipped
by the U.S. Mint to customers who ordered the numismatic coins.
U.S. Mint officials were unaware that Mint had released coins
missing the post-strike finish when contacted July 13 by Coin World.
Minnesota collector Aaron J. Gelner reported to Coin
World on July 12 that his local barber, Tom Schneider, had
received two of the Uncirculated 2010-P Grand Canyon National Park
5-ounce silver coins that day, one with the post-strike finish and one
without. Images of the two coins taken by Gelner are illustrated with
Connecticut collector Jim Scroggins on July 13 also reported to
Coin World his receipt of an Uncirculated 2010-P Grand
Canyon National Park 5-ounce silver coin missing the post-strike finish.
Unlike the bullion versions of the 5-ounce coins struck at the
Philadelphia Mint but intentionally without Mint mark, the numismatic
versions are produced with a P Mint mark on the reverse. The
Mint-marked numismatic versions also are supposed to receive a
The same ready-to-strike 5-ounce planchets received from supplier
Sunshine Minting from Coeur d’Alene, Idaho, for the bullion versions
are also used for the Uncirculated numismatic versions. However, the
numismatic coins undergo a “vapor blasting” technique after striking,
resulting in a finish replicating that used on 3-inch bronze Mint
medals, according to 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 exhibit prooflike