(1964-65) Blank Pattern - RB-5385, INCO

Coin Details

Description

INCO experimental quarter-sized blank RB-5385, continuing the transition beyond the intensive RB-53xx optimization series. This composition variant represents one of the compositions tested as the program moved from fine-grained parametric studies into broader exploration of alternative metallurgical approaches. The blank's survival is itself notable, as many experimental planchets from the INCO program were consumed in destructive testing — sectioned for microscopic examination of the clad bond interface, or subjected to accelerated aging tests that simulated years of circulation wear in a matter of weeks. The specimens that survive intact typically represent compositions that were retained as reference standards or that were produced in slightly larger quantities because they showed particular promise. RB-5385's preservation indicates it held enough interest to warrant retention through the decades since the experimental program concluded, making it a valuable physical record of a composition that the surviving documentation might not fully describe.

Rarity Notes

R-7 to R-8. Extremely rare surviving blank from the INCO experimental program.

Cross References

RB-5385 (Robinson-Breen catalog). INCO experimental blank planchet series, quarter-sized, 1964-65.