A strange gold error coin struck by the Royal Canadian Mint has been certified by PCGS recently. The $100 National Park gold commemorative coin program was introduced in 1985. The obverse features a portrait of Queen Elizabeth II, while the reverse features a Rocky Mountain Bighorn sheep. A rare mated error pair of Reverse Die Caps was produced during the minting process.
When a new planchet entered the press, another coin came in between the new planchet and the reverse die. An erroneous design was created on the new planchet and the design on the coin that came in between was distorted as well. The shape of the coin was also distorted as the coin was not held tightly by the die. This kind of a distortion is known as a brockage.
Since the dies were configured incorrectly, the obverse design of this die cap expanded after each impression. Finally, the error coin looked like a bottle cap. The coin was probably struck many times as it was a Proof coin, due to which, its diameter expanded by 30%.
The second coin of this mint error did not eject and struck the coin mentioned above. This created a brockage on the obverse of the second coin. Error coins like these rarely escape quality checks that are conducted at Royal Canadian Mint.
It is the second known gold die cap from any country. An 1824 English Half Sovereign obverse die cap which struck 2-3 coins, is very shallow and slightly cupped. The proof Canadian $100 Commemorative Gold Die Cap Mated Pair is a combination of deep reverse die caps and brockages.
Image courtesy: PCGS