(1965) Quarter Pattern - RB-4165, INCO

Coin Details

Description

The highest-numbered entry in the 1965 INCO experimental clad quarter series, RB-4165 represents the final quarter-denomination alloy variant tested during the second phase of composition evaluation. The substantial gap from RB-4145 to RB-4165 parallels similar jumps elsewhere in the experimental series, suggesting that alloys RB-4150 through RB-4160 were evaluated through means other than full die striking. As the concluding piece in the RB-4100 quarter sequence, RB-4165 may represent either an extreme composition at the boundary of acceptable performance parameters or a specially formulated control sample used for calibration purposes. The entire 1965 quarter testing program produced far fewer distinct compositions than the 1964 first phase, which had generated over 80 varieties — a compression reflecting the program's transition from broad exploration to targeted validation. RB-4165 was struck at the Medallic Art Company on standard Washington quarter dies, producing a piece visually identical to the billions of clad quarters that would soon enter circulation. These experimental quarters collectively document one of the most important materials science projects in American monetary history.

Rarity Notes

R-7 to R-8. Extremely rare. As the final entry in the RB-4100 quarter series, this may be among the scarcest 1965 experimental quarters.

Cross References

Research Blank RB-4165 (Gould/INCO experimental series)