A Proof is a specimen coin struck for presentation, souvenir, exhibition, or numismatic purposes. Before 1968, Proofs were made only at the Philadelphia Mint, except in a few rare instances in which presentation pieces were struck at branch mints. Today Proofs are made at the San Francisco and West Point mints.
The term Proof refers not to the condition of a coin, but to its method of manufacture. Regular-production coins (struck for circulation) in Mint State have coruscating, frosty luster; soft details; and minor imperfections. A Proof coin can usually be distinguished by its sharpness of detail, high wire edge, and extremely brilliant, mirrorlike surface. All Proofs are originally sold by the Mint at a premium.
Very few Proof coins were made prior to 1856. Because of their rarity and infrequent sales, they are not all listed in the regular edition of the Guide Book of United States Coins. However, in the Professional Edition, you will find them listed individually within their respective denominations.
Frosted Proofs were issued prior to 1936 and starting again in the late 1970s. These have a brilliant, mirrorlike field with contrasting dull or frosted design.
Matte Proofs have a granular, “sandblast” surface instead of the mirror finish. Matte Proof cents, nickels, and gold coins were issued from 1908 to 1916; a few 1921 and 1922 silver dollars and a 1998-S half dollar were also struck in this manner.
Brilliant Proofs have been issued from 1936 to date. These have a uniformly brilliant, mirrorlike surface and sharp, high-relief details.
“Prooflike” coins are occasionally seen. These are examples from dies that have been lightly polished, often inadvertently during the removal of lines, contact marks, and other marks in the fields. In other instances, such as with certain New Orleans gold coins of the 1850s, the dies were polished in the machine shop of the mint. They are not true Proofs, but may have most of the characteristics of a Proof coin and generally command a premium. Collectors should beware of coins that have been buffed to look like Proofs; magnification will reveal polishing lines and lack of detail.
After a lapse of some 20 years, Proof coins were struck at the Philadelphia Mint from 1936 to 1942, inclusive. During these years the Mint offered Proof coins to collectors for individual sale, rather than in officially packaged sets, as such.
In 1942, when the composition of the five-cent piece was changed, there were two types of this denomination available to collectors. The striking of Proof coins was temporarily suspended from 1943 through 1949, and again from 1965 through 1967; during the latter period, Special Mint Sets were struck (see page 366). Proof sets were resumed in 1968.
Sets from 1936 through 1972 include the cent, nickel, dime, quarter, and half dollar; from 1973 through 1981 the dollar was also included, and again from 2000 on. Regular Proof sets issued from 1982 to 1998 contain the cent through the half dollar. Specially packaged Prestige sets containing commemorative coins were sold from 1983 through 1997 at an additional premium. From 1999 to 2009, sets contain five different Statehood or Territorial quarters, and from 2010 to 2021, different National Parks quarters. In 1999 Proof dollars were sold separately. Four-piece Presidential dollar sets have been issued since 2007.
From time to time the Mint issues special Proof sets. One recent example is the four-piece 2009-S Lincoln Bicentennial set, which included each of the special cent designs issued that year, but coined in 95% copper (the Lincoln cent’s original 1909 alloy).