COIN "FINISHES" AND WHAT THE TERMS MEAN
One day I received a phone call from a dealer who wanted to purchase a number of commemoratives and sets from us. This gentleman had actually been out of the coin hobby for some time but was returning with lots of enthusiasm, and naturally we were delighted that he chose to work with us.
During our conversation he mentioned that he felt a little out of touch with the modern coin market and asked me to clarify for him what words were being used to describe the finishes on modern coins. It seemed to me that this would be a good idea for our CoinTalk department on the Euro Collections International website. On our site we use the terms "UNC", "BU" and "PROOF". Here then, based on how we use the terms on the site as well as my personal experience in the minting business, is what those terms mean.
UNC
This abbreviation stands for uncirculated. When we describe a coin as UNC it means that the coin has never been issued into circulation. As such the coin has only a small number of surface imperfections.
Such imperfections are common to UNC coins because of the manner in which most of them are struck. Given that such minting activities are focused on producing coins for circulation, the coins are usually produced in high speed automated coin presses often spitting out thousands of coins a minute. To feed those presses the blanks also have to be produced in mass quantities. When the coin press finishes striking a coin, it is usually ejected into a large metal bin for later counting and packaging. Sometimes the presses will even bag and seal the coins immediately, but in either scenario there are going to be bag scratches and other surface imperfections. If the coins receive relatively little handling and later on are packaged in rolls, such coins can be very free of surface scratches.
Some collectors actually prefer UNC coins because these are the coins which actually go into circulation.
BU
The next step up is "brilliant uncirculated", or BU. Here the minting process is dramatically different from that used for UNC coins. First, the blanks are prepared much more slowly and with a higher reject rate. As well, the blanks are polished. Also receiving a lot of polishing are the actually production dies used to mint the coins. With polished blanks and dies, mints then produce coins with completely mirrored finishes.
The number of coins made with each pair of production dies is many, many fewer compared with regular circulating coins. During the minting process each coin is made one at a time and the press operator during a shift will hand buff the dies frequently to make sure that they are free of any dust which might otherwise be struck onto the surface of the coin.
And after the coins are minted, a lot of effort goes into the final inspection process to weed out any sub-standard coins before they are sent on to be packaged.
Speaking of inspection procedures, I recall many years ago a conversation I had with a colleague of mine at the Royal Canadian Mint. He worked in production while I worked in marketing and we were discussing collectors who liked to collect "error" coins. I laugh when I remember him saying something like "I just don't understand those error collectors. I mean, gee, these are just imperfect coins which got past our quality control. I'd be glad to replace them with perfect ones any time."
Collectors who prefer BU coins consider them to be a more perfect specimen of a coin that would be made for circulation.
PROOF
Over the years this term has evolved. Today, however, it generally applies to coins which have frosted features and mirrored backgrounds, or fields. Sometimes coins can be described as "reverse proofs" meaning that the features are frosted while the field is brilliant.
The proof coin represents the height of the minter's craft. The same careful preparations are needed for proof coins as for bu's. But over and above that, special steps are taken to produce the frosted and mirror finishes.
The most important of these is the preparation of the production dies. Each die is first taped over with a special clear masking tape. Then a mint technical will use a very sharp knife and a microscope to carefully cut out and remove the tape covering those features to be frosted. Next the dies are blasted with glass beads. The protected areas are left brilliant and the areas to be frosted are, well, frosted. The dies are then ready to produce coins.
In theory, the mirror areas of a BU coin and a proof coin are equal, but in practice the proof coin is often subjected to more scrutiny and thus the overall quality can be higher.
Proof coins with large mirror fields are especially hard to produce. There can be problems with metal flow which can cause ripples in the field or other slight distortions. This is just one example of the problems mint engineers must solve in order to produce a perfect coin. Then too, there are the pitfalls in production. The smallest speck of dust or some other die imperfection can cause a problem on the finished coin and cause it to be rejected.
Proof coins represent the best a mint is capable of producing. The greatest amount of preparation, production resources and quality control go into these coins. It is therefore not surprising that among our customers, proof coins as singles and in sets are purchased most often.
In recent years, the term "cameo"* and "deep cameo"** are used to describe some proof coins. The PCGS coin grading service describes these terms and we have included them at the end of this article.
For a more in depth discussion of finishes, especially in relation to coin grades, I highly recommend "Official A.N.A. Grading Standards for United States Coins", published by the American Numismatic Association. While the focus of this book is US coins, the first 30 or so pages contain lots of information useful to any coin collector.
If your German reading skills are good, I also would recommend "Die deutschen Muenzen seit 1871" by Kurt Jaeger. Not only is it considered one of the references for German coin collectors, but its introductory section is full of useful information.
As always, happy coin collecting!!
Murray Church
Euro Collections International
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*"Cameo
The term applied to coins, usually Proofs and prooflike coins, that have frosted devices and lettering that contrast with the fields. When this is deep the coins are said to be "black and white" cameos. Occasionally frosty coins have "cameo" devices though they obviously do not contrast as dramatically with the fields as the cameo devices of Proofs do. Specifically applied by PCGS to those 1950 and later Proofs that meet cameo standards (CAM)."
**"Deep Cameo
The term applied to coins, usually Proofs and prooflike coins, that have deeply frosted devices and lettering that contrast with the fields - often called "black and white" cameos. Specifically applied to those 1950 and later Proofs that meet deep cameo standards (DCAM)."
Top see examples of coins that have been graded as "deep cameo", please click on this link: http://www.eurocollections.com/catalog/?category=291