What Are Reverse Proof Coins And How Are They Made?

PCGS - The United States Mint has been producing proof coinage since at least the mid-19th century and over the years has struck a wide variety of proofs - brilliant proofs, matte proofs, and cameo proofs among them. However, in more recent years the U.S. Mint has begun producing a new type of proof coin. This newfangled offering, known as the reverse proof, provides a specially struck proof coin wherein the devices, inscriptions, and other raised portions of the coin boast mirror-like resilience and the fields - the sunken flat areas - are frosted. This is a complete reversal of the more traditional proofs, with the frosted devices and lettering contrasted against mirrored fields.


2006-P Reverse Proof American Silver Eagle. Courtesy of PCGS TrueView. Click image to enlarge.

While mints around the world have been implementing reverse proof technology for some time now, it's a relatively new concept for the U.S. Mint, which first released reverse proof coins in 2006. Reverse proofs were struck by the United States Mint on a fairly sporadic basis until only the past few years, when they have become something of a mainstay offering - if still a novel one in its own right.

Proof coins are made using highly polished planchets that are struck with specially prepared planchets. The dies themselves are carefully selected dies and must be in virtually perfect condition. Historically, the dies were treated with acid to create frosted devices, which are sunken on the die while the fields are polished - thus providing the traditional cameo-mirror contrast. With the rise in digital technology, the mint uses a computer-aided laser to produce the frosted texturing on proof dies, and this allows coiners to impart the frosting on virtually any part of the die.

Minters can now direct the frosted texturing on the fields while polishing the devices and other sunken areas on the die, thus creating the reverse proof. This same laser technology has helped give rise to diverse coin finishes that were never even technologically feasible just a few decades ago. The mold was certainly broken with reverse proof coins, which are now one of the most popular offerings in the U.S. Mint catalog.

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