Numismatic Guaranty Company® (NGC®) is the world's leading authority on mint errors, a popular segment of numismatics. In Mint Error Coin Chronicles, we take an in-depth look at a specific kind of mint error. This month's topic is the Rotated Dies Error.

US Mint coins are struck with coin alignment. That means that if you hold a coin with your fingertips at 3 o'clock and 9 o'clock and rotate the coin, the reverse will be properly oriented (and not upside down). A Rotated Dies Error occurs when the reverse is askew relative to the obverse. NGC will recognize rotated die mint errors only if there is at least 15 degrees of rotation.

The Rotated Dies Error is much more common on early US Mint coinage, such as this 1846-O Quarter Eagle that is graded NGC Mint Error AU 53. The eagle on the reverse is nearly horizontal (instead of vertical, as would be expected), indicating a significant amount of rotation. This particular coin is part of a Heritage Auctions sale in February 2024.



Rotated Dies Errors tend to occur when a die is installed improperly or is loose and rotates on its own. And they can occur on world coins, as well. Many world coins are struck with medallic alignment. That means if you place your fingertips at 12 o'clock and 6 o'clock and rotate the coin, you will see the other side properly oriented.

This Macau 1997 10 Patacas is graded NGC Mint Error MS 61 for a Rotated Dies Error. It was supposed to be struck with medallic alignment, but instead it looks like it was struck with coin alignment (sometimes called "coin turn.") This coin is part of a Spink auction in January 2024.



These errors can command a significant premium over coins that are struck in the expected fashion. Here are a few examples of prices realized through Heritage Auctions for coins with a Rotated Dies Error:

• A 1922 Double Eagle graded NGC Mint Error MS 63 realized $2,115 in August 2013.
  
  
• An 1847-O Eagle graded NGC Mint Error XF 45 realized $2,070 in February 2012.
  
  
• A Cuba 1988 Piefort Gold 10 Pesos graded NGC Mint Error PF 69 Ultra Cameo realized $2,040 in November 2020.
  
  
• A 1989-D Congress Silver Dollar Commemorative graded NGC Mint Error MS 69 realized $1,782 in February 2009.
  
  
• A 1973-S Kennedy Half Dollar graded NGC Mint Error PF 67 Cameo realized $1,560 in July 2021.
  
  
• A 1923 Peace Dollar graded NGC Mint Error MS 63 realized $1,527 in February 2016.
  
  
• A 1913 Type 1 Buffalo Nickel graded NGC Mint Error MS 66 realized $456 in April 2022.
  
  
• A 1966 Jefferson Nickel graded NGC Mint Error MS 65 realized $276 in January 2009.
  
  
• A 1968-S Quarter graded NGC Mint Error PF 68 Ultra Cameo realized $144 in October 2021.
  
  
• A 1943 Lincoln Cent graded NGC Mint Error UNC Details realized $114 in September 2023.