This was the first attempt at an international coinage.
The following is excerpted from Pollock.
In June 1867 an international monetary convention was held in Paris to consider the adoption of an international gold coinage. The different nations agreed that the international unit should be based on the French franc. A coinage bill was introduced calling for the creation of a United States five dollar coin weighing 124-9/20 grains - rather than the standard 129 grains - which would equal the proposed 25 franc piece.
France and Great Britain produced similar pieces as well. To see these pieces, click
Examples were struck as follows:
Copper with reeded edge J656/P729 with about a dozen known, several of which have been gilted.
Copper with plain edge J657/P730. This appears to be the rarest of the 4 with about a half dozen known, several of which have been gilted.
Aluminum with reeded edge J658/P731 with about a dozen known.
Aluminum with plain edge J659/P732 with about a dozen known.
Many of the latter 2 show corrosion.
For additional information on other patterns for international coinage, click here.
A new book has been written by Steven Reti which discusses some of the history surrounding these pieces. For more information click here.
A gold example with plain edge was discovered in July 2002. In the opinion of several prominent numismatists, it is believed to be a fake. To view, click here.