The major error coin of the Indian Head denomination was verified only recently. Rumored to have existed for decades, the 1859 Obverse Mule -- both sides of the coin struck with obverse dies -- surfaced in 2000. Its appearance utterly amazed even the most experienced error experts. It sold to Legend Numismatics for $33,350 in the 2000 Superior Pre-Long Beach Sale.
1859 Obverse Mule/PCGS MS62
1864/Multlple Strike Counterbrockage
A counterbrockage error involves a capped die and a previously struck coin. When a capped die strikes a previously struck coin, the obverse design from that struck coin will be impressed into the cap. The result will be a design where the cap face will be an incuse brockage. When a new blank gets struck by this capped die with an incuse brockage image, the obverse will have a raised and spread image from the incuse design of the cap. The below example is an extreme case in which the cap struck 4 or possibly 5 counterbrockage strikes before it was removed or broke away from the die, giving the coin the shape of a bottle cap. It was featured in the 12/01 issue of Longacre's Ledger and is owned by Fly-In-Club President Chris Pilliod.
1869/struck on silver dime planchet/PCGS AU55
A coin struck on a planchet intended for another denomination or of the wrong metal is known as a wrong planchet error. They're very rare in this series, with approximately ten believed to exist. They include 1863, 1864-L, 1868, 1893, 1900, 1905 and 1908.
The 1869 imaged below was struck on a Seated dime planchet. Note that the planchet is too small for the larger sized Indian cent dies.