(1964-65) Blank Pattern - RB-6100, INCO

Coin Details

Description

The opening entry of the RB-61xx subseries, RB-6100 inaugurates a new group of experimental blank planchets within the broader RB-6xxx program. The jump from RB-6060 to RB-6100 signals a categorical transition to a different family of alloy compositions, incorporating changes in the fundamental layer architecture, the use of different base metals, or modifications to the cladding process itself. Where the RB-60xx blanks explored variations within a single alloy system, the RB-61xx series may represent an entirely different metallurgical approach — compositions with thicker or thinner cladding layers, different core alloys, or the introduction of specialized barrier layers between the cladding and core to prevent interdiffusion during manufacturing. The RB-6100 blank preserves the first composition in this new experimental family, establishing the baseline against which subsequent RB-61xx variants would be compared. Its physical appearance — the surface color, edge layer visibility, weight, and dimensions — would immediately reveal whether the new alloy family produced blanks with a fundamentally different character from the RB-60xx group.

Rarity Notes

R-7 to R-8. Extremely rare. The transition to a new alloy family within the RB-6xxx series makes this blank of particular cataloging significance.

Cross References

RB-6100 (Robinson-Breen catalog). INCO experimental blank planchet series, RB-61xx group, 1964-65.