1964 Quarter Pattern - RB-1145, INCO

Coin Details

Description

An INCO experimental quarter with the RB-1145 alloy composition, representing one of the later entries in the 1100-series of test strikes produced for the US Treasury's silver replacement evaluation. These pieces played a direct role in one of the most consequential decisions in modern American coinage: the transition from precious metal to base metal coinage. The RB-1145 variant was tested alongside dozens of other compositions, each evaluated for a complex matrix of performance criteria including striking quality, surface hardness, corrosion resistance, electromagnetic properties, and manufacturing cost. The data gathered from these test pieces informed the Treasury's recommendation to Congress and ultimately shaped the composition of every US quarter minted since 1965.

Rarity Notes

Extremely rare experimental piece with very few known survivors. INCO test strikes were produced in strictly limited quantities for evaluation purposes.

Cross References

Reed-Brenner RB-1145; NGC census