The Numismatic Bibliomania Society



The E-Sylum: Volume 26, Number 30, July 23, 2023, Article 20


Separately from his interview series for the Newman Numismatic Portal, error collector Greg Bennick has been profiling experts in the error field for ErrorScope, the publication of the Combined Organization of Error Collectors of America (CONECA). Occasionally we share one with permission here in The E-Sylum. Here's the first of four parts of Greg's interview with collector and writer Mike Diamond, covering Mike's introduction to error collecting. Many thanks to Greg, ErrorScope Editor Allan Anderson, and CONECA for making this available here. -Editor

Greg Bennick: Mike, thanks for taking some time to answer some questions today. Can you tell me a little about your background?

Mike Diamond headshot Mike Diamond: Well, I'm semi-retired now. I work as a freelance writer. I write for Coin World. I used to be a teacher, teaching biological anthropology and cultural anthropology. Before that I taught human gross anatomy and other courses necessary for basic health sciences. I have a Ph.D. in biological anthropology from the University of Chicago. Coins are a hobby that allow me to exercise my brain. I haven't done any active scientific research for quite a while, so this keeps my neurons firing and lets me work on my writing skills, too.

Greg Bennick: How did you get involved with error collecting? How and when did that come about?

Mike Diamond: I had a brief flirtation when I was in high school in the early 1970s, and quite probably it started when I picked up Frank Spadone's terrible book on errors, which I didn't know was terrible at the time. (Note: Major Variety and Oddity Guide of United States Coins, by Frank G. Spadone, Krause Publications, Iola WI)

Greg Bennick: Right?!

Mike Diamond: Yes, I got a copy of that. That sparked my interest.

Greg Bennick: Can you tell us a bit about the Spadone book? I have copies of multiple editions of it on my shelf and I flip through them from time to time. What was it for you about that book that leaves you saying today that it was terrible because it is indeed, not the best book.

Mike Diamond: (Laughs) It was riddled with fakes! It is riddled with counterfeits and altered coins. You name it. And some the terminology is idiosyncratic, and then you've got the pictures. I knew about the 1943 bronze cent for example and then I see, Oh, wow. There's a triple struck one! (laughs) Yeah, right. They were all fake.

Greg Bennick: I'd be very curious to know about Spadone himself. I don't know anything about him, like where he was from and what inspired him to write the book and whatnot.

Mike Diamond: I'm sure he's led many a hobbyist astray. But yeah, I don't know any background material about him. Once I went to college, I forgot about errors for years and years and years. I picked it up again in 1997 when I went to a coin show and I picked up two coins, one of which was an error, the other of which was a fake. But I didn't find out about that for several years. Anyway, that got me rolling. When I went to the show. I wasn't sure whether I wanted to collect error coins or paper currency, and I'm glad I made the decision I made!

Greg Bennick: What were the two coins that you bought? The real, or authentic one, and the fake one?

Mike Diamond: Well, the authentic one was a dime, a clad layer struck off center. I'm not sure if it's a uniface strike on top of a normal dime planchet or if it separated after the strike. Those two errors, unless there are some clues that you can pick up on, are essentially indistinguishable. Anyway, it was a struck clad layer. And the other one was, I thought, an incomplete punch. But it turned out to be a fake.

Greg Bennick: I most certainly have made my mistakes over the years. I remember buying a 1964 off-center Kennedy silver half dollar with a brockage reverse on the bourse floor in Baltimore. And I thought for sure that I made the purchase of the century and then sent it in to PCGS and it came back in a body bag. And it turned out to be a fascinating educational piece as Fred Weinberg and I would later discuss. It seems there was a series of these 1964 fake brockages which came out around that time and we talked about who made them all. It's pretty interesting what you can learn when you get burned, so to speak. The key if you buy the wrong thing is to stay devoted to your education about why the coin is fake and how to discern an authentic one.

Mike Diamond: You know, on the rare occasions these days when I do buy a fake, I just write it up for Coin World and make lemonade out of a lemon.

Greg Bennick: So, given that it was the late 1990's, you moved relatively quickly from getting back into errors to starting to work on the Error Coin Information Exchange on Yahoo! Groups and I'm assuming that you started writing articles shortly thereafter as well? How did you start writing about error coins?

Mike Diamond: I tried to read everything there was to read. Arnie Margolis' book (Note: The Error Coin Encyclopedia, Third Edition by Arnold Margolis and Fred Weinberg) and Alan Herbert's book (Note: Official Price Guide to Mint Errors, by Alan Herbert, House of Collectibles, New York) and James Wiles short course, and some of the older references too. I also got hold of back issues of ErrorScope. I read through all of them. I read everything I could and I learned everything I could, and then I went beyond it.

Greg Bennick: You certainly went beyond it! Which of those references was most inspirational to you? I'm wondering if the Herbert book was indeed the one that was most central to you, because your work, seemingly as a scientist of sorts of the minting process, follows methods that Herbert seemed to approach with his book. His book was very, very specific in the error types it explored. I was wondering if that book was particularly inspiring for you?

Mike Diamond: I would say Herbert's book and Margolis' book were equally informative. Herbert's a little bit more technical. His classification is odd. We don't need to go into that. But they were both useful. I also found this older book, Steiner and Zimpfer's Modern Mint Mistakes (Note: Ideal Printing Company, LaPorte, Indiana). It was an older book, but still quite useful.

Greg Bennick: Absolutely. A classic with amazing photos, too.

Mike Diamond: Kind of grainy actually in terms of the quality of the photos. Black and white, and the resolution's not great, but certainly good enough to show what they wanted to show.

Greg Bennick: I agree. I think for the time, the early seventies, I believe 1971 or 1972, it was tremendous.

More of Greg's error interviews can be found in previous issues of Errorscope magazine. For more information on the Combined Organization of Error Collectors of America (CONECA), see:

Wayne Homren, Editor

NBS ( Web

The Numismatic Bibliomania Society is a non-profit organization promoting numismatic literature. See our web site at

To submit items for publication in The E-Sylum, write to the Editor at this address:

To subscribe go to:



Copyright © 1998 - 2023 The Numismatic Bibliomania Society (NBS)
All Rights Reserved.

NBS Home Page
Contact the NBS webmaster