Coin and Paper Money Collecting/Mint Marks and Proofs

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Expert: - 5/15/2009


Question
I recently acquired a penny collection and I am getting confused on proofs.  Are all "s" mint marked pennies proofs and if not how do I figure out if I have a proof or not when I see a "s".

Answer
Hi Jason,

Good Question.  The U.S. Mint started making proof coins at the SF Mint in 1968.  Some years have both a business strike and proof strike in the same year.  Normally, you can tell a proof by the mirror like fields and cameo portrait - although not all proof coins will be cameo all will have mirrored fields.  There is no doubt a contrast between a proof and business strike.  Proof only coins stared in 1975.  So any cent dated 1975 to date with an "S" Mint Mark is a proof.  You might consider buying "A Guide Book to United States Coins" or sometimes called the Red Book.  This book is a great reference for the beginner.

Please remember to never clean coins, this can damage and lessen their value.  Also, soft plastics can contain harmful chemicals that can react with coins over time.  Try using inert materials when storing coins.  Plus, it is always a good idea to store coins in a safe.  The safe should not be exposed to the elements and should not be up against a wall to the outside.  These are just a few tips I have learned over the years to help keep your collection in top shape.

If you found this information helpful please nominate me for category expert in coins.  If coming through Los Banos, CA please feel free to look us up at Thoreson Numismatics, 947 6th Street, Los Banos, CA  93635.  209-826-0777.

Thanks for the question,

Troy Thoreson, aucpro.com  

Coin and Paper Money Collecting

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Troy Thoreson

Expertise

Please, no error coin questions unless your coin is dated 1955 or before. I can answer questions regarding all U.S. Coins, Gold & Silver bullion, including regular mint and proof issue coins and currency. Since 2009, I have been contributing to the Red Book, "A Guide Book of United States Coins", by R.S. Yeoman along with two other publications. I currently run two coin shops in California.

Experience

I have over 30 years experience in Numismatics. I own two coin shops and have examined thousands of coins over the years. Please allow up to 2 business days for an answer. This is a free service and I am happy to answer questions - but please be patient and understanding of my time.

Organizations
My company is an authorized P.C.G.S. and N.G.C. dealer. I am a Life Member of the American Numismatic Association and California State Numismatic Association. We are also an authorized Whites Metal Detector dealership.

Publications
I have written articles for Coin World and the Rare Coin Market Report.

Education/Credentials
I have a certificate of completion from the American Numismatic Association on how to detect counterfeit U.S. Gold Coins and how to Grade U.S. Coins along with other certifications. I have a Bachelor of Science in Business with a concentration in Accounting and a minor in Computer Information Systems.

Awards and Honors
I am listed as a contributor to the Red Book, "A Guide Book of United States Coins", the Red Book, by R.S. Yeoman. I have been contributing to the Red Book since 2009. I also contribute to the Blue Book and the new Professional edition Red Book. I have many other awards and honors.

Past/Present Clients
My past consulting clients included eBay, Inc., Yahoo! Auctions, and the United States Postal Service. I have many other great customers and help all no matter their level of collecting.

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