(1964-65) Blank Pattern - RB-5300, INCO

Coin Details

Description

The opening entry of the RB-5300 subseries within INCO's experimental blank planchet program, RB-5300 marks the beginning of a new group of quarter-sized blank compositions distinct from the RB-5200 series. The jump in catalog numbering from the RB-52xx range to RB-5300 signals a shift to a different family of alloy compositions — exploring an alternative cladding thickness, a different core alloy, or the introduction of additional alloying elements not present in the RB-5200 formulations. The International Nickel Company maintained parallel research tracks during the silver replacement study, investigating multiple metallurgical approaches simultaneously rather than pursuing a single line of development. This strategy ensured that if one alloy family proved unworkable for technical or economic reasons, alternative approaches were already at an advanced stage of testing. RB-5300 represents the starting point of one such alternative track for the quarter-sized denomination, embodying a composition that differed fundamentally from the RB-5200 series in its approach to replicating the critical properties of 90% silver coinage.

Rarity Notes

R-7 to R-8. Extremely rare experimental planchet. The transition to a new numbering sequence adds cataloging significance.

Cross References

RB-5300 (Robinson-Breen catalog). INCO experimental blank planchet series, quarter-sized, 1964-65. Opens the RB-5300 composition group.