1964 Quarter Pattern - RB-2505, INCO

Coin Details

Description

Experimental quarter struck in the RB-2505 alloy composition by INCO and Medallic Art Company during the 1964 clad coinage development program. This piece follows immediately after RB-2500 in the Reed-Brenner catalog, representing the first incremental adjustment within the RB-25xx sub-series. The five-unit spacing between catalog numbers in this sub-series — consistent with the RB-22xx and RB-23xx groups — indicates that INCO maintained the same systematic approach to varying individual metallurgical parameters throughout the entire RB-2xxx family. The RB-25xx compositions were formulated with the benefit of extensive data from earlier test series, allowing INCO's metallurgists to focus their experiments more narrowly on the most promising region of the alloy composition space. This increasingly targeted approach is reflected in the relatively compact range of the sub-series: whereas the RB-22xx group spanned eight compositions (2200-2235) and the RB-23xx group spanned eight as well (2340-2375), the RB-25xx group encompasses sixteen compositions (2500-2575), indicating a more intensive investigation of a particularly promising alloy family. Each test strike produced by Medallic Art Company was carefully documented with its exact composition and processing history, though survival of this documentation has been uneven.

Rarity Notes

Extremely rare. Single-digit population estimated. The RB-25xx sub-series survives in very limited quantities.

Cross References

RB-2505 (Reed-Brenner), NGC ID: 61890