1964 Quarter Pattern - RB-2375, INCO

Coin Details

Description

The final entry in the RB-23xx sub-series of INCO experimental Washington Quarters, cataloged as RB-2375. This piece marks the endpoint of one particular line of alloy investigation within the broader 1964 clad coinage research program. As the concluding composition in its sub-series, RB-2375 may represent either the most refined version of the alloy family explored in the RB-23xx range or the compositional boundary beyond which further adjustment produced diminishing returns. The gap between this piece (RB-2375) and the next known composition (RB-2500) is the largest within the RB-2xxx family, spanning 125 catalog numbers. This substantial gap indicates a significant discontinuity in the testing program — a shift from one fundamental approach to cladding (such as varying the nickel-to-copper ratio in a ternary alloy system) to an entirely different metallurgical strategy (such as changing the core composition or layer thickness ratio). The Reed-Brenner catalog's numbering gaps thus contain important information about the structure of INCO's research program, even in the absence of surviving specimens for the intervening numbers.

Rarity Notes

Extremely rare experimental piece. Population be in the range of 1-3 specimens. As the terminal composition in its sub-series, this piece carries particular research significance.

Cross References

RB-2375 (Reed-Brenner), NGC ID: 61888