(1965) Quarter Pattern - RB-4100, INCO

Coin Details

Description

The first entry in the 1965 INCO experimental clad quarter series, RB-4100 opens the second phase of quarter-denomination composition testing that followed the extensive 1964 program (which used RB-1000 through RB-3000 series numbers for over 80 quarter variants). Struck on Washington quarter dies at the Medallic Art Company under INCO's direction, this piece tests a specific copper-nickel clad alloy formulation on the quarter's larger planchet, where performance characteristics such as strike quality, edge appearance, and electromagnetic profile could differ significantly from the same alloy on a smaller dime blank. The quarter denomination posed unique challenges for the transition from silver: its larger size made weight differences between silver and clad more perceptible to users, and the greater surface area amplified any visual discrepancies in color or luster. INCO's metallurgists addressed these concerns through careful calibration of the nickel content in the cladding layers, aiming for a surface color that would read as silver-white rather than the yellowish tone that copper-heavy alloys tend to produce. The 1965 quarter experiments refined compositions that had shown promise in the 1964 first phase, narrowing the field toward the final production specification.

Rarity Notes

R-7 to R-8. Extremely rare. Most 1965 INCO experimental quarters survive in specialized pattern collections or institutional archives, with fewer than 10-15 specimens estimated for each variety.

Cross References

Research Blank RB-4100 (Gould/INCO experimental series)