Learn Grading: What is a Proof Coin?

Posted on 8/13/2019

Mints around the world have created several new types of Proofs in recent years. Learn what they are and how NGC attributes them.

NGC uses a numeric grade to succinctly describe a problem-free coin's condition. The numeric grade is typically preceded by an abbreviation that indicates the way the coin was struck and, for circulation issues, its approximate condition.

Coins are struck in a growing range of formats. The two most common types are circulation issues and Proofs.

Circulation issues, which are also called “business strikes,” are coins that are made for commerce or struck in the same manner as coins that are made for commerce. For grades 60 and higher, circulation issues receive the MS prefix to indicate that they are in “Mint State” (Uncirculated). In lower grades, the prefix is an abbreviation for the coin’s adjectival grade range. For example, circulation issues that grade 50, 53, 55 and 58 receive an AU prefix to indicate that they are in About Uncirculated condition.

Proof issues are coins that are specially struck for collectors with highly polished dies and planchets. These coins traditionally feature frosted design elements and mirrored fields.

An Enhanced Reverse Proof and a Modified Proof coin. Click images to enlarge.

In recent years, mint arounds the world have developed other types of Proofs, which can sometimes look dramatically different. These types are described below.


A traditional Proof coin—and still the most common type of Proof coin—is one that has a frosted appearance on the devices (the raised parts of the design) and a mirrored finish on the part of the coin without design, known as the fields. Proof coins graded by NGC feature PF (for Proof) before the grade, as in PF 70.

The contrast between the frosted design elements and mirrored fields is called a “cameo effect.” The degree of contrast is described by NGC with the Cameo or Ultra Cameo strike characters that follow a Proof coin’s numeric grade, as in PF 70 Ultra Cameo. In cases where there is little-to-no cameo contrast, no strike character will be used.

NGC uses the Cameo and Ultra Cameo strike characters with traditional Proofs only. Other strike characters such as BN, RB or RD may be used with other types of Proofs, however. Learn more here.

An example of a Proof coin: a 2018 Proof Silver Eagle graded NGC PF 70 Ultra Cameo. Click images to enlarge.

The Silver Eagle pictured above is a regular Proof. It shows strong contrast between the deeply mirrored fields (which appear black) and the frosty white devices, which appeals to collectors. For centuries, this was the only type of Proof. In recent years, however, mints have upgraded their technology to create new and distinctive Proof variations. One of the first examples of this is the Reverse Proof coinage struck by the US Mint.

Reverse Proof

An example of a Reverse Proof coin: a 2012-S Reverse Proof Silver Eagle, graded NGC PF 69. Click images to enlarge.

Not surprisingly, on a Reverse Proof the design elements are mirrored while the fields are frosted—the exact opposite of a traditional Proof. This type of coin was first issued by the US Mint in 2006 for the 20th Anniversary of the Gold and Silver Eagle program. It has since been used on numerous other issues from around the world.

NGC describes these coins with the term REVERSE PF before the numeric grade, as in REVERSE PF 70. Previously, these coins were described as PF 70 REVERSE PROOF.

Enhanced Reverse Proof

An example of an Enhanced Reverse Proof coin: a 2019-W Enhanced Reverse Proof Silver Eagle, graded NGC PF 70. Click images to enlarge.

Much more recently, the US Mint has created Enhanced Reverse Proof. This finish features selective frosting on the design elements that would otherwise be fully mirrored on a Reverse Proof. In the coin shown above this selective frosting is particularly evident on Liberty’s dress and the shield on the reverse.

Enhanced Reverse Proof was enabled by new technology at the US Mint that allows for multiple levels of frost using computer-controlled lasers. This type of Proof has been used infrequently thus far. Coins struck in Enhanced Reverse Proof include the 2019-W Silver Eagle from the Pride of Two Nations Set and the 2019-S Kennedy Half Dollar in the Apollo 11 50th Anniversary 2019 Proof Half Dollar Set.

NGC describes these coins with the term ENHANCED REV PF before the numeric grade, as in ENHANCED REV PF 70. Previously, these coins were described as PF 70 ENHANCED REV PF.

Modified Proof

An example of a Modified Proof coin: a 2019 Canada Silver Maple Leaf $5 Modified Proof, graded NGC PF 70. Click images to enlarge.

In addition to an Enhanced Reverse Proof Silver Eagle, the 2019 Pride of Two Nations included a Modified Proof Canadian Silver Maple Leaf. This is the first coin to be described as Modified Proof, which the Royal Canadian Mint says has inscriptions that are unfrosted as well as laser-etched features such as the maple leaves around the perimeter of both the obverse and reverse.

NGC describes these coins with the term MODIFIED PF before the numeric grade, as in MODIFIED PF 70.

As mints around the world continue to upgrade their technology and experiment the range of Proofs and other formats seems destined only to increase. It will be exciting to see what new formats will be offered in the coming months and years.

All types of Proof coins are listed separately in the PF section of the NGC Census.

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