The United States Mint is investigating why edge collars featuring two different reeding styles were used at the West Point Mint to strike 2015 American Eagle tenth-ounce gold bullion $5 coins.

Numismatic Guaranty Corp. posted photographic evidence Jan. 22 on its website to illustrate the differences in what the grading service is attributing as the Wide Reeds and Narrow Reeds edge varieties.

NGC claims this is the first time that a variation in reed sizes on the edge of any American Eagle bullion coin has been noted.

Coin World has requested an explanation from the U.S. Mint as to why two different style collars (the part of the die setup that produces the edge-reeding) were used and the reed count for each.

The Wide Reeds variant has the standard size reeding produced by edge collars used in the production of American Eagle gold bullion coins in prior years.

The Narrow Reeds edge style, according to NGC, exhibits “much smaller and finer reeds that are more tightly spaced than those seen on prior issues."

This is the first time the Narrow Reeds edge style has been used on American Eagle tenth-ounce gold bullion coins, according to NGC.

The standard Wide Reeds variety appears more abundant in the coin submissions to NGC thus far for the 2015 tenth-ounce gold coins.

All four sizes of 2015 American Eagle gold bullion coins first went on sale from the U.S. Mint to authorized purchasers in the first week of January.

All American Eagle bullion coins are struck at the West Point Mint, but without the W Mint mark.

Three dies used in the production of the American Eagle coins — an obverse, a reverse and an edge or collar die.

The collar die restrains the flow of metal of the planchet during striking to retain a uniform diameter. The edge design on most coins  is imparted during striking, whether plain, reeded, or ornamented in some other form.

“Traditionally, reeds were used on precious metal coinage to indicate during circulation that no metal had been removed from a coin’s edges,” according to NGC. “This feature, along with raised edge lettering, has been employed on all precious metal U.S. coins since 1836.

“All American Eagle coins have reeded edges,” the remarks from NGC observe.

More from CoinWorld.com:

2015 Ultra High Relief 24-karat gold coin from U.S. Mint to carry $75 denomination

Error allows U.S. Mint customers to order and receive Proof 2015-S U.S. Marshals Service half dollars early

2015 American Eagle silver bullion coins being struck only at West Point Mint currently

All 2015 Kennedy half dollars to bear 1964 obverse design sculpt employed on 2014 50th Anniversary coins

ANACS reports first example of Missing Edge Devices error for Enhanced Uncirculated 2014-D Native American dollar

Please sign in or join to share your thoughts on this story.

Keep up with all of CoinWorld.com's news and insights by signing up for our free eNewsletters, liking us on Facebook, and following us on Twitter. We're also on Instagram!