(1964-65) Quarter Pattern - RB-3120, INCO

Coin Details

Description

Test quarter in the RB-3120 experimental composition from INCO's 1964-65 clad coinage development program. The ten-unit gap from RB-3110 to RB-3120 — skipping RB-3115 — introduces a larger increment than the five-unit spacing seen in the immediately preceding entries, indicating that compositions between these values were tested in laboratory form but not coined, or that the parameter being varied could be meaningfully explored at coarser intervals. The Reed-Brenner catalog records these gaps faithfully, preserving information about the structure of INCO's experimental design even where not every planned composition resulted in a surviving test strike. RB-3120 falls in the upper range of the RB-31xx sub-group, approaching the transition to the RB-32xx compositions that would close out the entire INCO experimental program. At this advanced stage, the testing program was focused on validating the production readiness of promising compositions rather than discovering fundamentally new alloy systems. The practical challenges of scaling up from experimental test strikes to full-scale Mint production were substantial: the bonding process for clad strip material needed to work reliably on industrial-width strip at production line speeds, and INCO's late-phase testing helped verify that the compositions which performed well in small-batch test strikes would also perform well under these demanding conditions.

Rarity Notes

Extremely rare. Estimated population of 1-3 known examples. The gap from RB-3110 indicates selective testing at wider compositional intervals in this region.

Cross References

RB-3120 (Reed-Brenner), NGC ID: 61911