1964 Quarter Pattern - RB-2550, INCO

Coin Details

Description

Test quarter struck in the RB-2550 experimental alloy, one of the final compositions in INCO's RB-25xx sub-series of 1964 clad coinage test pieces. This Washington Quarter-format experimental piece represents a near-terminal data point in the most densely populated sub-series of the entire RB-2xxx family. The RB-25xx compositions span from RB-2500 to RB-2575 in sixteen documented formulations, making this the most thoroughly explored alloy family in the INCO program. By the time RB-2550 was being produced and evaluated, the research team had narrowed their leading candidates to a small number of compositions that met all of the Treasury Department's requirements. The remaining test strikes in the sequence — RB-2550 through RB-2575 — may represent final confirmation tests designed to verify that the selected composition was indeed optimal, or they explored edge cases and alternative formulations that could serve as backup options if production-scale manufacturing revealed problems with the primary candidate. In either case, RB-2550 occupies a position of particular significance within the testing program, representing the point at which fundamental research was transitioning into final validation.

Rarity Notes

Extremely rare. Estimated population of 1-3 specimens. The terminal portion of the RB-25xx sub-series is among the scarcest in the entire INCO program.

Cross References

RB-2550 (Reed-Brenner), NGC ID: 61898