Late error coin dealer Len Roosmalen used to call truly incredible errors "wowsers" in his catalog descriptions, and I always loved that designation. While I won't take his term as my own, lets honor him and use it where it applies, like with the mated pair upon which I am focused in this issue of Mint Error News.

The reason I love writing for Mint Error News is largely you, and I mean that sincerely. I always know when I start a column that no matter how dramatic, how interesting, how bizarre an error coin (or in this case, "coins") I have in front of me, that the readership of Mint Error News will appreciate what I have to share. You love exciting, dramatic, and dare I say, expensive mint errors. And this month, this issue allows me an opportunity, yet again, to share exactly that.

This is a particularly interesting mated pair. Instead of consisting of two coins of the same planchet size - which is what one often sees with mated pairs - this pair is multi-denominational. This is a 1966 Washington quarter double struck on a dime planchet (though not noted as double struck), mated with a 1966 quarter with a full brockage by a Washington quarter struck on a dime planchet (which yes, you guessed it, is the first coin of the pair).

The two coins were struck together at the same time and the net result is essentially two error coins in one, though we get to observe them separately as they didn't bond together permanently from the strike.

You might ask how we know the dime planchet coin is double struck as we don't see evidence of a second strike? Proof that the dime was double struck is actually on the other coin. It is found in the brockage image on the quarter. That brockage image shows the exact design elements still present on the quarter struck on the dime planchet. The quarter on dime was struck once, then rested obverse down on the quarter planchet when the quarter was struck by quarter dies. This impressed the quarter-on-dime obverse into the reverse of the quarter on quarter. Whew! Errors can sound confusing! But if you think it through, it makes perfect sense.

This pair offers a fantastic opportunity to further study the minting process. How would a dime end up being struck by quarter dies? In coin production process during this era, planchets were toted from one location in the mint to another in tote bins. The same is true today. When planchets are made they have to be transported to the dies and tote bins are an easy way to do that. Today, the totes and die press machinery are color coded to help prevent what I am about to describe from happening.

After dime planchets were made, they were poured into the tote bin to be transported to the dime press in order to be struck into dimes. A small thin lip at the bottom of the tote bins often would catch planchets. A dime planchet very well have could have been stuck in the metal lip at the bottom of that tote bin when additional dime planchets filled that bin. Later, all - or supposedly all - were dumped into the dime press. That planchet stuck in the lip remained with the bin, and stayed there when the bin was reused.

When that same tote bin with the stuck dime planchet was then used and filled with quarter planchets for quarter production, and quarter planchets were dumped into that tote bin, those planchets could have dislodged the dime planchet which then was mixed in with the quarter planchets. That dime made its way through the quarter production process and was struck once by quarter dies. It then rested on top of a quarter planchet and was double struck, with its obverse image impressed into that quarter. Voila! The mated pair before us. And you can now see how the dime and quarter, very well, could have been struck together at the same time by the dies, with one resting right on top of the other.

Today the minting process is slightly different. Totes are color coded, as I mentioned, to match the press/dies for that denomination. This prevents dime blanks, for example, from ever coming into contact with the quarter production process. This makes this multi-denominational mated pair an incredible piece of history and even more rare as replicating it today is far more difficult if not impossible.

Lucky for us, this happened in 1966, because it creates an amazing error, a collecting rarity, and a learning opportunity as well. Multi denominational mated pairs are very rare, and whenever they come up for sale, they command high prices and are worthy as desirable items, and rightly so. The minting conditions under which they are manufactured are certainly not seen anymore. In addition, even back them, the resulting errors didn't always make it out of the mint, and even if they did, perhaps one piece did and the other did not. So, to have both coins is exceptional.

If you happen to have any questions about this pair and how it was made, please feel free to email Mike Byers or me anytime you can reach me at mint errors@gmail.com. If there's any part of the minting process you're interested in, or any error types you'd like to see showcased in future articles, feel free to let me know. Be sure to put "Mint Error News" in the subject line so I know where your question came from.

Thank you for letting me share this wowser of a multi-denominational mated pair. I'm thankful that you read about it along with me. I look forward to sharing more incredible error coins with you in the future!