BG- 504, 1854 California Gold Rush Circulating Fractional Gold $1, Liberty Octagonal Eagle Reverse PCGS MS63 R5

This variety is mostly collected for its popular Liberty Head/Large Eagle devices. The reverse of the BG-504, which was struck by Frontier, Deviercy & Co., roughly imitates the famous U.S. Assay Office $50 slugs of the early 1850s. This is an example of Breen-Gilleo Die State III with a radial crack through left-side star upon the reverse.

BG-504 is one of only four Breen-Gillio octagonal dollar varieties to present the Assay Office eagle on the reverse, the others being BG-502, BG-503, and BG-534. PCGS has graded 9 as MS63, with 9 finer. Collectors Universe prices this variety at $9,000.00. BG-504 is listed in the Guide Book as the "Liberty Head / Large Eagle" variety, which further drives collector demand.

How were such coins struck? Frontier, Deviercy & Co. had a German or French coin screw press from the 1830s. (The image of the screw press is above. Photo: Stack’s January 2011 New York Americana Sale.) A detailed report in Coinweek.com explains the process:

Mechanically, this screw type press is operated by a long, hand-thrown centrifugal rod at the top, which causes a thick 2″ screw to be pressed down. As the screw presses down it pushes on a square shaped length of iron that moves up and down and imposes considerable force on the hammer die which is mounted at its base. An ingenious feature is the square shape of the iron driving rod, this mitigates the rotational force from the screw action that would otherwise torque the hammer die and cause uneven striking.

The direction of the hammer die is straight downward where it meets the planchet that is held in place by a collar and supported on the lower die, thus striking the impression into the planchet to create a coin.