The famous 1884 trade dollar struck in copper. As with most die trials made from the 1860s onward, these were deliberately struck. The two known examples were presented to A.M. Smith.
His first was sold as lot 245 in Bolender's 10/35 sale and the other was sold as lot 25 in Bolender's 2/36 sale as part of a partial 1884 copper proof set from the quarter to the double eagle that was offered individually.
Both known examples have since been silver-plated. The Anderson-Dupont, Emmons, Delp example was presented to the Smithsonian in 1979. To view the Smithsonian piece, click here.
The second piece, illustrated above is ex Kreisberg 6/65, Superior 75 ANA, Hughes 7/80, Dr. Linkner, ANR 1/04, Heritage 4/17, Wyoming collection - PCGS60.
Photo courtesy of American Numismatic Rarities.