How to Find an 1870-S Seated Liberty Half Dime

The 1870-S Seated Liberty half dime is unique in private hands—only one example is known, and according to official Mint records, none were ever struck at all. Its existence went completely unrecognized by the numismatic community until a collector unknowingly bought it as an ordinary type coin in 1978.

GetCoinHunt helps you search inventory from multiple coin dealers in one place and create a wishlist alert. For a coin this singular, that alert exists mainly to flag any claimed listing for serious scrutiny.

What makes the 1870-S half dime historically significant?

Official Mint mintage records list zero half dimes struck at San Francisco in 1870, even though the branch had half dime dies on hand that year. The accepted explanation, documented in PCGS CoinFacts’s and the numismatic trade press’s research on the issue, traces to a specific event: San Francisco Mint Coiner J.B. Harmstead documented a request to strike one example each of several coin denominations for inclusion in the cornerstone of the Mint’s new branch facility building—a time-capsule tradition. That request included denominations not otherwise produced there in 1870, among them the half dime, the silver dollar, and the $3 gold piece. The half dime made for that purpose appears to be the sole 1870-S half dime ever struck, and somehow it escaped the cornerstone and entered circulation, or at least private hands, rather than staying sealed inside the building.

The coin’s existence wasn’t recognized by collectors for over a century. Per accounts in the numismatic trade press, it was purchased in early 1978 as an unremarkable common-date type coin—its rarity unrecognized by the seller—then exhibited at that year’s American Numismatic Association convention after its significance was identified, and reportedly sold soon after for roughly $425,000 to Michigan dealer John Abbott. It has changed hands since; Heritage Auctions sold it in January 2023 for a record $3,120,000, and it currently carries a PCGS MS64 grade with CAC approval.

How to evaluate a claimed 1870-S half dime

Understand there is only one

With a single documented specimen and a traceable ownership history running from its 1978 rediscovery through its 2023 sale, any coin presented as a second 1870-S half dime should be treated as almost certainly not genuine.

Confirm the specific specimen and its pedigree

A legitimate offering of the known coin would come through a major auction house with full, verifiable provenance—not through ordinary dealer inventory.

Insist on current, verifiable certification

Given the coin’s value and uniqueness, only certification directly verifiable with PCGS should be considered credible for any claimed example.

Know the physical specifications

Per U.S. Mint records and PCGS CoinFacts, a Seated Liberty half dime of this type weighs 1.24 grams, measures 15.5mm in diameter, is struck in 90% silver, and has a reeded edge. These specifications describe the type generally; they are not, on their own, sufficient to authenticate a coin claimed to be this specific unique specimen.

Suggested search terms and filters

A search for “1870-S half dime” in ordinary dealer inventory should be expected to return no results. With only one specimen known and its full history documented, that’s the expected outcome.

Availability and pricing notes

The coin’s most recent public sale was $3,120,000 through Heritage Auctions in January 2023. It is not a coin that turns up in routine dealer listings, and any future sale would almost certainly happen through a major auction house.

How the GetCoinHunt wishlist alert works

1. Search for the coin to confirm nothing questionable is currently listed.
2. Add it to your wishlist so you’re notified if a legitimate auction offering is ever detected.
3. Treat any match with serious scrutiny, confirming it against the coin’s documented pedigree and current certification before considering it credible.

Frequently asked questions

How many 1870-S half dimes exist?

Only one is known. Official Mint records show zero half dimes struck at San Francisco that year.

Why was an 1870-S half dime struck if none were officially recorded?

The accepted explanation is that it was made specifically for inclusion in the cornerstone of the new San Francisco Mint building, along with single examples of three other denominations not otherwise produced there that year.

How was the coin discovered?

It went unrecognized until early 1978, when it was purchased as an ordinary type coin. Its true rarity was identified afterward, and it was exhibited at that year’s American Numismatic Association convention.

What did it most recently sell for?

$3,120,000, sold through Heritage Auctions in January 2023—a record for the issue. It currently carries a PCGS MS64 grade with CAC approval.

Can I realistically buy an 1870-S half dime?

Only if the single known specimen is offered again, almost certainly through a major auction house. It is not a coin available through ordinary dealer inventory.

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