The so-called transitional eagle with 'In God We Trust' on the reverse. This reverse was adopted in 1866. This forms part of a set along with the half eagle J445/P517 and double eagle J452/P524.
These are believed to have been struck in 1865 although they may also have been restruck in the early 1870s.
According to the June 1870 Mason & Co sale, two examples of this design were struck in gold J449/P521 - Farouk's and the illustrated piece in the Smithsonian which was acquired in 1892. It is unclear which piece was the one offered in the 1870 sale although traditionally it has been placed with the Farouk coin. Earlier owners of that piece include Woodin, Newcomer, Col Green and Boyd.
About a dozen are known in copper J450/P522 of which several have been gilted. The first definite appearance of this design was in the April 1870 auction by John Haseltine of coins from the Idler collection. A possible earlier listing may be Cogan's September 1869 sale.
Photo courtesy of the National Numismatic Collection of the Smithsonian Institution.