(1965) Dime Pattern - RB-4000, INCO

Coin Details

Description

An experimental clad dime struck as part of the second phase of the International Nickel Company (INCO) composition testing program conducted in 1965. While the first phase in 1964 used the RB-2000 series catalog numbers and established baseline performance data for various copper-nickel clad alloys on dime-sized planchets, these 1965-dated pieces refined the evaluation following the passage of the Coinage Act of 1965, signed by President Lyndon Johnson on July 23 of that year. The Act formally authorized the replacement of silver with copper-nickel clad coinage for dimes and quarters, making these later test pieces part of the verification process rather than the initial exploratory phase. RB-4000 was struck on Roosevelt dime dies at the Medallic Art Company of New York under contract to INCO, which had a direct commercial interest in supplying nickel for the new clad coinage. Each RB number in the 4000 series represents a distinct alloy formulation, varying the proportions of copper, nickel, and potentially other trace elements in the cladding layers and the core. These pieces were never intended for circulation and exist in very limited numbers, typically retained in INCO corporate archives or distributed to Mint officials as reference specimens during the transition away from silver coinage.

Rarity Notes

R-7 to R-8. Extremely rare, with most INCO experimental pieces surviving in institutional collections or among advanced pattern specialists. Fewer than 10-15 specimens are estimated for most RB-4000 series varieties.

Cross References

Research Blank RB-4000 (Gould/INCO experimental series)