Glossary
Dip
Dipping uses a chemical solution to remove toning or surface film. Done carefully it may restore brightness; done poorly it can strip luster …
Numismatics Coin FAQ
A collecting-focused glossary for coin terms, minting vocabulary, and evaluation basics.
Glossary
Contact Marks
Contact marks are hits, ticks, or abrasions from one coin touching another or hard surfaces. Location, severity, and visibility influence …
Glossary
Proof
A proof coin is specially made with extra care, often using polished dies and planchets to create sharp details and mirrored fields. Proof …
Glossary
Double Die
A doubled die is created when a die receives misaligned impressions during hubbing, producing doubled design elements on coins struck from …
Glossary
Whizzing
Whizzing is a mechanical alteration using a wire brush or rotary tool to simulate luster. It leaves unnatural texture and is considered …
Glossary
Certification
Certification is third-party authentication and grading, typically encapsulating the coin in a labeled holder with an ID number that can be …
Glossary
Bag Marks
Bag marks are small nicks and scuffs from coins contacting each other in mint bags or bulk storage. They’re common on large coins and …
Glossary
Cleaning
Cleaning is any attempt to remove dirt or discoloration from a coin’s surface. Improper cleaning can permanently reduce value by …
Glossary
Semi-Key Date
A semi-key date is less rare than a key date but still scarce enough to carry a premium and slow down collectors trying to complete a …
Glossary
Sheldon Scale
The Sheldon Scale is the 1-70 grading system widely used for U.S. coins, where higher numbers represent better preservation, luster, and …