(1965) Quarter Pattern - RB-4110, INCO

Coin Details

Description

Experimental clad quarter RB-4110 from the 1965 INCO testing program, representing a third alloy variation for the quarter denomination. The RB-4100 series quarters built upon the massive body of data accumulated during the 1964 first-phase experiments, in which INCO had tested dozens of alloy combinations to identify those with optimal electromagnetic compatibility with existing silver-detecting coin mechanisms. By 1965, the field had been narrowed considerably, and the RB-4100 series pieces focused on fine-tuning rather than broad exploration. This shift in purpose is reflected in the tighter spacing of RB numbers in the quarter series (4100, 4105, 4110, etc.) compared to the wider gaps in the dime series, suggesting more granular compositional adjustments. Each piece was struck on Washington quarter dies at the Medallic Art Company, INCO's preferred contractor for converting experimental blanks into fully struck coins. The resulting test pieces allowed evaluation of not just the alloy's physical properties but also its behavior under the extreme pressures of the coining process, where temperatures, metal flow characteristics, and die fill patterns all influenced the final product's quality and appearance.

Rarity Notes

R-7 to R-8. Extremely rare, with most specimens held in private collections. The tight compositional spacing of the RB-4100 series makes individual varieties difficult to distinguish without metallurgical analysis.

Cross References

Research Blank RB-4110 (Gould/INCO experimental series)