Collectors of Britannia silver bullion coins now have a pair of “mules” to consider.

Appropriately enough, a Year of the Horse coin is at the center of the error.

Approximately 17,000 examples of the 2014 Britannia 1-ounce silver £2 coins were struck with an obverse die intended for the Royal Mint’s inaugural Lunar bullion issue, celebrating the Year of the Horse in 2014. In addition, an estimated 38,000 examples of the Year of the Horse 1-ounce silver £2 coin were struck with an obverse die intended for the Britannia £2 coin.

Britannia mules in marketplace

Examples of the Britannia coin struck with the wrong obverse die have entered the marketplace, but so far, apparently, none of the Year of the Horse mules have traded in the market.

A “mule” in coinage results when two dies not intended to be paired together are used to strike coinage. The word “mule” plays off the animal that is the offspring of a male donkey and female horse.

The Ian Rank-Broadley effigy of Queen Elizabeth II graces the obverse of both versions of both coins. A generally tiny but significant detail on the obverse makes the difference.

On standard examples of the Year of the Horse coin, no dentils are found about the rim; the standard Britannia coin has dentils. All Britannia coins are supposed to have dentils inside the rim on both sides of the coin, while both sides of the Year of the Horse coins are designed without dentils.

The reverse of the Britannia coin shows the classic Philip Nathan design of Britannia (the female personification of the British Isles). A horse appears on the reverse of the Lunar Year of the Horse bullion coins.

Both 2014 coins are .999 fine silver, matching the new fineness adopted for Britannia bullion coins in 2012. Diameters, weights and other specifications are the same.

The Royal Mint confirmed the existence of both error coins, though an official did not specifically refer to either piece as a “mule.” Calling the dentils “edge decoration,” Jenny Manders, a spokesperson for the Royal Mint, released a statement noting that, “Some of our recent bullion customers may have noticed a slight change in the design of the edge decoration of our UK 2014 £2 Britannia bullion coin, and the UK 2014 £2 Lunar bullion coin. ... The quality and value of the coins remains the same.”

As with other mule coins, the value of the errors is considered much higher than the standard versions of the respective coins.

While Coin World had not confirmed sales of either mule coin, several of the Britannia design with the improper obverse are currently offered at online auction site eBay.com and the United Kingdom platform, eBay.co.uk. Buy it Now prices ranged from about $600 to $700 and their equivalent in British pounds.

Chuck Daughtrey of Modern Coin Mart said that firm sold an undisclosed quantity to a buyer who wished to remain anonymous. Daughtrey and fellow MCM employees Hayden Tubbs and David Ward helped discover the error.

Daughtrey said that world coin staff members there noticed that Modern Coin Mart’s images at its website did not match the coins being sold, and requested “correct” images.

It was photographer David Ward who alerted Daughtrey to the existence of the Britannia coins lacking the dentils on the obverse.

“[He asked me] if I had taken the original images for the Britannia coins, to which I replied that I had. He continued by asking if I could have mistakenly coupled the obverse image of one coin with the reverse image of a different issue. I told him that wasn’t possible because I photographed both sides and edited both sides of that coin individually, not as a part of a stack. So naturally the images I took were, without a doubt, of both sides of a single piece,” Daughtrey said.

Ward and Tubbs discovered that both correct and incorrect examples of the  coin were in stock, and then Tubbs contacted the Royal Mint’s bullion manager, Nick Bowkett, for explanation. Tubbs received the same statement from the Royal Mint that was provided to Coin World.

Daughtrey said he is aware of a few sales through eBay but noted, “As far as we know there has not been any widespread market awareness of these mule error coins. ... for the most part it remains a widely unknown yet very obvious error.”

Coin World knows of no other major distributor of bullion coins explicitly offering the mule versions, and thus far, only the mule Britannia coins have surfaced.

The Year of the Horse coin was released beginning Nov. 25, 2013, and was limited to a mintage of 300,000 coins. Manders said the Royal Mint has sold more than 38,000 examples of the Year of the Horse coin, but the ratio of mules to proper examples is not known. Until more details emerge, either through sales records of Year of the Horse mules or mintage figures from the Royal Mint, collectors won’t know whether the mule version is more common than the properly struck issue.

The annual Britannia coin has an unlimited mintage, and became available in the United States about the first week of December.

New for the 2014 Britannia coins is a legend change on the reverse, to read 1 OZ 999 FINE SILVER, replacing the previous wording, ONE OUNCE FINE SILVER.

The 1-ounce silver £2 coins weigh 31.21 grams and measure 38.61mm in diameter.