(1964-65) Blank Pattern - RB-5215, INCO

Coin Details

Description

INCO experimental blank planchet RB-5215, a quarter-sized unstruck test piece in yet another alloy composition from the silver replacement evaluation series. The systematic variation of alloy compositions across the RB-5200 sequence reflects INCO's scientific approach to the coinage problem. The company's metallurgical research division, headquartered in Suffern, New York, maintained one of the world's most advanced facilities for developing and testing nickel-based alloys, and this expertise was directly applied to the Treasury's urgent need for a silver substitute. Each blank in the series represented a specific point in the multidimensional space of possible alloy compositions — varying the percentages of nickel, copper, zinc, manganese, and other elements produced blanks with subtly different colors, hardnesses, densities, and electromagnetic signatures. RB-5215's specific composition would have been documented in INCO's internal records alongside detailed measurements of its physical and electrical properties, creating a dataset that Treasury evaluators could use to map the relationship between alloy composition and coinage performance.

Rarity Notes

R-7 to R-8. Limited production for evaluation purposes. Many blanks from the program were sectioned or destroyed during testing.

Cross References

RB-5215 (Robinson-Breen catalog). INCO experimental blank planchet series, quarter-sized, 1964-65.