(1965) Quarter Pattern - RB-4145, INCO

Coin Details

Description

Experimental clad quarter RB-4145, with the skip from RB-4135 indicating that RB-4140 was either tested as an unstruck blank only or produced in insufficient quantity to enter the numismatic record. Gaps in the RB numbering sequence are common throughout the INCO experimental program, as not every composition that was prepared as a blank was necessarily struck into a coin. Some alloys was rejected during preliminary testing for obvious deficiencies — cracking during rolling, unacceptable color, or density outside the target range — and never progressed to the die-striking stage. RB-4145 survived this initial screening and was struck on Washington quarter dies at the Medallic Art Company, producing a fully realized test coin that could be evaluated for all the qualities required of a circulating quarter: visual appearance, strike quality, edge definition, stackability, and electromagnetic compatibility with coin-operated machinery. The piece stands as physical evidence of an alloy formulation that passed INCO's internal quality threshold but may or may not have met the final specifications adopted by the U.S. Mint for production coinage.

Rarity Notes

R-7 to R-8. Extremely rare. The gap from RB-4135 to RB-4145 indicates intermediate compositions were not struck as coins, making surviving struck pieces from this range particularly scarce.

Cross References

Research Blank RB-4145 (Gould/INCO experimental series)