In Heritage's 2010 April-May Milwaukee, WI CSNS US Coin Auction #1139 they featured a bizarre example of territorial coin production, a Clark Gruber Twenty Dollar Overstruck on a U.S. 1850 Ten Dollar, graded MS63 PCGS. Lot 2388
Although numerous die trials or fantasy pieces are known for the 1861 Clark, Gruber coinage, this was the first such example we have seen of this particular combination, and as such it is probably unique.
Heritage handled a similar coin, an 1861 Clark, Gruber struck over an 1853 U.S. Assay Office twenty in 2002. About that lot and Clark, Gruber overstrikes in general, guest cataloger Donald Kagin wrote:
" We now know of five overstruck Clark Gruber & Co. twenties... Originally we believed that these specimens were overstruck in Philadelphia by the firm who designed the dies--the jewelers Bailey & Company. After further research and discussions with other numismatists, including John Dannreuther of the Professional Coin Grading Service, we now believe that these were struck in Colorado by Clark, Gruber & Co. to check the force of the striking and the spacing of the dies. This would account for the variance of the pressure and sharpness of the impressions.
These set-up pieces are not unlike other similar types such as those seen for Morgan dollars, Kennedy half dollars, and others. Before striking the regular gold blanks, which would have been considered quite precious even then, these test or trial strikings allowed the dies to first be properly aligned and avoid errors. They are recognizable because their central area is well to fully struck, while the periphery is weak or missing. Evidently the coiners would take whatever gold coins they had on hand to test the new dies."
Since the planchet for the gold eagle is considerably smaller than the Clark, Gruber twenty dollar die, portions of the design are off of the flan — but the date 1861 is quite legible for the Clark, Gruber, with the 1850 date from the eagle slightly up the margin to the right. PIKES PEAK is visible at Liberty's coronet; the LIBERTY from the 1850 coin lies across the Clark Gruber Liberty's cheek. The obverse Clark, Gruber design is doubled, clearly struck twice with die rotation between strikes, as is the reverse. On the reverse, ARK GRUBER & CO DEN is clear but jumbled near the rim, with TEN D . UNITED STATES OF AMER seen underneath. The doubled shield design of the Clark Gruber overstrikes can be clearly seen — again, all intermixed with the design details of the federal eagle in the center. This piece is brilliant orange-gold and has original luster throughout, clearly a "keeper" piece that never saw circulation.
Whatever its reason for existence, it is a fascinating and possibly unique piece of Americana.