(1964-65) Quarter Pattern - RB-3105, INCO

Coin Details

Description

An INCO experimental Washington Quarter designated RB-3105 in the Reed-Brenner catalog, representing the first incremental variation from the RB-3100 baseline within the RB-3xxx family of 1964-65 clad coinage test pieces. The five-unit spacing between RB-3100, RB-3105, and RB-3110 reintroduces the fine-grained parametric approach that characterized the RB-2xxx family, applied here to a different base alloy system. This indicates that the RB-3100 composition showed sufficient promise to warrant detailed exploration of nearby formulations, with INCO's engineers systematically varying individual metallurgical parameters to map performance within this new alloy family. The 1964-65 date range on these pieces places them at the heart of the transition period: the Coinage Act had been signed in July 1965, but the Mint did not begin full-scale production of clad coins until later that year, and INCO was conducting final validation testing on production-grade strip material during this period. These late-program test strikes may thus represent the closest approximations to the actual production alloy, produced under conditions that most closely replicated the Mint's full-scale manufacturing process.

Rarity Notes

Extremely rare. Population estimated at 1-3 specimens. Fine-increment variations within the RB-31xx sub-group are among the scarcest INCO patterns.

Cross References

RB-3105 (Reed-Brenner), NGC ID: 61909