(1965) Quarter Pattern - RB-4135, INCO

Coin Details

Description

INCO experimental clad quarter RB-4135, a late-series entry in the 1965 quarter composition testing program. As one of the higher RB numbers in the quarter sequence, this piece tests a composition near the end of the evaluation matrix, representing an alloy with modified trace-element content or an adjusted bonding process for the clad layers. The International Nickel Company's experimental program was notable for its thoroughness: rather than testing a handful of compositions and selecting the best performer, INCO evaluated dozens of variants across multiple denominations, building a comprehensive database of alloy performance data that would inform coinage metallurgy for decades. The RB-4135 quarter was struck on standard Washington dies at the Medallic Art Company, maintaining the program's consistent methodology of testing experimental alloys under realistic striking conditions. The transition from silver to clad coinage represented the most significant change in American coin composition since the abandonment of gold coinage in 1933, and the experimental pieces that enabled this transition constitute an important chapter in modern numismatic history.

Rarity Notes

R-7 to R-8. Extremely rare. Higher RB numbers in any given series tend to be among the scarcest, as later experiments sometimes produced fewer specimens.

Cross References

Research Blank RB-4135 (Gould/INCO experimental series)