1870-S

The San Francisco Mint produced just 17,000 half eagles in 1870, a tiny figure consistent with the modest gold output of the early 1870s. The Coronet With Motto design carried the relatively new IN GOD WE TRUST banner above the eagle, a feature added in 1866 to all gold denominations of $5 and larger. The year 1870 has become legendary in numismatics because of the unique 1870-S three-dollar gold piece and the unique 1870-S half dime, both regarded as among the rarest American coins ever struck. The half eagle is the obtainable companion to those mythical pieces. While not in the same impossible tier, it remains a scarce branch-mint date that pairs naturally with discussions of San Francisco gold production during Reconstruction-era America.

Authentic examples weigh 8.359 grams and measure 21.6 millimeters in diameter, struck in the standard 90 percent gold and 10 percent copper alloy with a reeded edge. The S mintmark sits on the reverse beneath the eagle and should appear cleanly punched into the field. Because branch-mint half eagles of this era have been targeted by counterfeiters and by altered-mintmark fraud, weight checks and side-by-side mintmark comparisons against verified PCGS or NGC plate coins are essential. Genuine pieces typically show San Francisco die characteristics including softness in the eagle's right wing tip and slightly grainy fields from working dies pressed hard during a low-mintage run. Any coin that fails the weight tolerance or shows a tooled or oddly shaped mintmark should be set aside for professional authentication.

Survival estimates place the total population at roughly 100 to 150 examples across all grades, with the great majority in circulated condition between Very Fine and About Uncirculated. Mint State coins are genuinely rare, with only a handful certified at the major services and finest examples reaching the MS62 range. Auction results from Heritage and Stack's Bowers show attractive AU pieces trading in the four to low five-figure range, while certified Mint State examples have crossed $40,000 in strong markets. The 1870-S sits among the recognized scarcities of the San Francisco half eagle sequence and rewards patience in waiting for an honest, problem-free coin. For full design history and the broader sequence of dates, see the Liberty Head Half Eagle series history.