Mint Error Coin Chronicles: Broadstrikes

Posted on 8/10/2021

Coins that lose their collars end up running loose beyond their boundaries.

Numismatic Guaranty Corporation® (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 Broadstrikes.

A Broadstrike error occurs when a coin is struck without a collar, which is the retaining ring that establishes the final diameter of a newly struck coin. With no collar to constrain the planchet, the coin will expand beyond the boundary of a normal coin, sometimes drastically so.

In order to qualify as a Broadstrike, the coin’s full design must be present on both faces. If the design is cut off on either face, the error is called an “Off-Center Strike.” The difference between the two errors is often easy to spot. Compare the two images below:

1968 India 3 Rupees with a Broadstruck Mint Error.
Click images to enlarge.

Notice that the Broadstrike Error includes the entire coin design, while this dramatic Off-Center Strike Error features only a portion of the coin design.

1988-D Half Dollar with an Off-Center Strike of 80%.
Click images to enlarge.

A number of interesting Broadstrike Error coins are being showcased in upcoming auctions. This 1971-S Eisenhower Dollar displays a classic Broadstrike Error. Because the collar die didn’t deploy during mintage, the diameter of the coin expanded nearly evenly during the strike, slightly further on the lower obverse and upper reverse than elsewhere. This coin (lot 4439) is being offered by Heritage Auctions in Auction #1333, being held August 18-22, 2021.

1971-S Eisenhower Dollar graded NGC MS 66 with a Broadstruck Mint Error
Click images to enlarge.

This next coin, a 1973-S Kennedy Half Dollar illustrates the old adage "If one thing can go wrong, so can many more." Not only does the coin display a Broadstrike Error, but it also is Double Struck. First, the collar die was not in its proper position when this Kennedy Half was minted, resulting in a fairly even expansion of the planchet outside the coin’s diameter. But something else went wrong during the second strike of this Proof coin that led to a slight rotation of the die and a faint “ghosting” of the images on the obverse and reverse. This coin (lot 44306) is being offered by Heritage Auctions in Auction #63166, ending August 26, 2021.

1973-S Kennedy Half Dollar graded NGC PF 68 Cameo with Double Struck and Broadstrike Mint Errors
Click images to enlarge.

Double errors such as the one on the above Kennedy Half are exciting finds for collectors. This China Empire (1905-08) 10 Cent was estimated to sell between $100 and $200 in a Stack’s Bowers sale in April 2021. Instead, it realized $720, reflecting hobbyists’ appreciation of such unique error combinations.

China Empire (1905-08) 10 Cent graded NGC AU 50 BN with Broadstrike and Brockage on Reverse Mint Errors
Click images to enlarge.

The Broadstrike Error is evident on the obverse (holdered toward the back) as a distortion of the coin’s image placement, which seems to be pushed to the left side, leaving a portion of the right side blank. A Brockage Error (holdered toward the front) can be seen on the reverse of the coin as a mirror image of the obverse. Brockage Errors are caused when an already-minted coin sticks to the coin die and impresses into another coin. This results in a reversed and incuse impression of the design on the coin.

Several other NGC-certified Broadstrike Error coins are being offered in The Aug. 26 Heritage sale, including:

  • a 1918 Lincoln Cent graded NGC AU 58 with a Broadstrike Mint Error (lot 44012)
  • a 1919-S Lincoln Cent graded NGC AU 55 with a Broadstrike Mint Error (lot 44015)
  • a 1973-S Kennedy Half Dollar graded NGC PF 68 Cameo with Double Struck and Broadstrike Mint Errors (lot 44307)
  • a 1973-S Clad Eisenhower Dollar graded NGC PF 68 Cameo with Double Struck and Broadstrike Mint Errors (lot 44319)

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