US Coins

Error-variety online glossary under preparation

An effort is under way to construct a comprehensive illustrated glossary of every known category of die variety and minting error.

Called the Error-Variety Ready Reference, it can be found online at

Each entry has a definition, explanation, and photographs of representative specimens. At least 850 entries are planned. Currently, approximately 350 to 400 entries have been completed.

The editor-in-chief of the project is Coin World’s “Collectors’ Clearinghouse” author Mike Diamond. Diamond is responsible for finalizing each entry. BJ Neff, Jeff Ylitalo and Jason Cuvelier serve as contributing editors.

Error coin dealers Fred Weinberg and Jon Sullivan serve as consulting editors. Neff set up and maintains the website. He is responsible for its layout and organization.

The glossary is built on a scaffolding provided by the Comprehensive Error-Variety Checklist, a 22-page classification compiled by Diamond several years ago. The checklist is available on the website and is periodically updated.

A listing of completed glossary entries can be found in the checklist of completed entries.

Whenever possible, links are provided to online articles on the relevant subject. The site will be continually updated.

Visitors seeking information on an entry that has not yet been completed can contact the editors using the “Contact Us” section to ask that the matter be expedited. ¦

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