(1964-65) Blank Pattern - RB-5330, INCO

Coin Details

Description

Experimental quarter-sized blank planchet RB-5330 from the INCO program. This blank represents one of the later entries in the dense cluster of RB-53xx compositions, documenting a formulation that had advanced far enough in INCO's screening process to warrant physical planchet production. The blank planchet itself — smooth, round, and unadorned by any design — might appear unremarkable to the casual observer, but to a metallurgist it is a rich source of information. The surface finish reveals the alloy's response to the tumbling and annealing processes used in planchet preparation. The edge cross-section shows the architecture of the clad layers — their thickness, the sharpness of the bond line between cladding and core, and any evidence of interdiffusion between the layers during the bonding process. The weight and dimensions confirm whether the alloy's density is compatible with the existing quarter-dollar specifications. And the color of the blank, viewed under controlled lighting conditions, indicates whether the composition would produce coins whose appearance the public would accept as a credible replacement for the silver coinage they were accustomed to handling.

Rarity Notes

R-7 to R-8. Rare institutional specimen from the INCO experimental blank evaluation program.

Cross References

RB-5330 (Robinson-Breen catalog). INCO experimental blank planchet series, quarter-sized, 1964-65.