This is a unique mated pair of the only known reverse die caps for any Canadian gold coin.
Coin #1 is a Canadian Gold $100 Reverse Die Cap. The Royal Canadian Mint issued this coin in 1985. It is the $100 National Park Commemorative Coin. The obverse depicts Queen Elizabeth II and the reverse depicts a Rocky Mountain Bighorn sheep.
After being struck, Coin #1 adhered to the reverse die and became a reverse die cap striking blank planchets that created a brockage on the reverse of each coin.
The obverse design of this die cap expanded with each strike. As with any reverse die cap, the shape resembles a bottle cap with deep walls. This gold die cap struck a large number of coins as the diameter expanded.
This proof gold reverse die cap (Coin #1) is more than 30% larger in diameter than a properly struck commemorative.
Coin #2 is also a Canadian Gold $100 Reverse Die Cap. After being struck, this coin adhered to the reverse die becoming a reverse die cap. It subsequently struck Coin #1 creating a brockage on the obverse of Coin #2, resulting in this phenomenal mated pair. As with any reverse die cap, the shape resembles a bottle cap.
It is incredible that this dramatic gold die cap mated pair was discovered and subsequently sent to PCGS for authentication and grading. Furthermore, there is only one other known gold die cap from any country. It is an 1824 English Half Sovereign obverse die cap, which struck only two or three coins and is very shallow and slightly cupped. By comparison this proof Canadian $100 Commemorative Gold Die Cap Mated Pair combines several major mint errors; deep reverse die caps with brockages that were mated and struck multiple times.
These are two of the rarest, most expensive and most spectacular Canadian Mint Errors known. This unique proof gold die cap mated pair rivals any U.S. Gold Mint Error in rarity, prestige and value. In fact, there are no known U.S. gold obverse or reverse die caps and only two known U.S. gold brockages.