(1965) Dime Pattern - RB-4025, INCO

Coin Details

Description

Experimental clad dime RB-4025 from INCO's 1965 composition testing program, representing a further alloy variation struck on Roosevelt dime dies. This piece is part of the systematic evaluation that followed the Coinage Act of 1965, which authorized the Treasury Department to proceed with clad coinage production. Although the basic copper-nickel clad concept had been validated during the 1964 first-phase experiments, specific parameters of the alloy continued to be tuned throughout 1965 and into early production. The RB-4025 formulation differs from its neighbors in the series by subtle adjustments to nickel content in the cladding layers, copper purity in the core, or the bonding process used to laminate the layers together. INCO's testing infrastructure at the Medallic Art Company allowed rapid iteration through alloy variants, with each composition struck on genuine U.S. Mint dies to produce realistic test pieces that could be evaluated under conditions identical to actual coinage production. The resulting pieces occupy a unique position in American numismatics: they are neither official Mint products nor purely private manufactures, but rather collaborative experimental specimens produced at the intersection of government policy and private industry.

Rarity Notes

R-7 to R-8. Extremely rare, with an estimated fewer than 10 specimens known. Most examples remain in private pattern collections or institutional archives.

Cross References

Research Blank RB-4025 (Gould/INCO experimental series)