1866 Proof Nickel Pattern - J-478

Coin Details

Description

Part of the extended Shield Nickel alloy testing series, J-478 explores how the adopted design performs in a different metallic composition. The Act of May 16, 1866, specified a coin of 77.16 grains composed of 75% copper and 25% nickel, but the Mint continued testing alternatives even after the legislation was enacted — Congress could amend the specification if a superior alloy was identified. The nickel content was particularly important: pure nickel was too hard and caused excessive die wear, while too little nickel produced a coin that looked too similar to copper cents. The 75/25 copper-nickel ratio proved to be the sweet spot, producing a light silvery color with acceptable hardness, and would eventually become one of the most successful coinage alloys in American history.

Rarity Notes

R.6 to R.7. Approximately 10-15 examples survive.

Cross References

Pollock-3546