1964 Quarter Pattern - RB-2520, INCO

Coin Details

Description

Test strike in the RB-2520 experimental composition from INCO's 1964 clad coinage development program. This Washington Quarter-format test piece belongs to the middle portion of the RB-25xx sub-series, which represents the most densely populated region of INCO's experimental matrix. The RB-2520 formulation would have been evaluated alongside its immediate neighbors — RB-2515 and RB-2530 (with RB-2525 apparently skipped or tested but not struck into coin form) — to determine the sensitivity of key performance metrics to small compositional changes. The absence of RB-2525 from the known catalog is noteworthy: gaps within an otherwise regular five-unit sequence typically indicate either that the composition was tested in sheet form but not coined, that specimens were produced but none have survived, or that the particular formulation was deemed redundant with an adjacent composition. These internal gaps provide insight into the decision-making process within INCO's research program, revealing where the engineers decided that additional test strikes would not yield useful new information. The RB-2520 piece itself would have undergone the full battery of evaluations: color measurement, hardness testing, wear simulation, electromagnetic analysis, and striking quality assessment.

Rarity Notes

Extremely rare. Population be in single digits. The concentration of compositions in the RB-25xx range makes individual varieties particularly difficult to distinguish without laboratory analysis.

Cross References

RB-2520 (Reed-Brenner), NGC ID: 61893