The Ghost Coins of 1870-S: How the San Francisco Mint Created a Numismatic Legend
In 1870, San Francisco officials lowered a copper casket into granite.
They meant to mark a beginning.
Instead, they created one of the greatest mysteries in American numismatics.
The ceremony honored the cornerstone of the second San Francisco Mint. That building later earned the nickname “The Granite Lady.” It still stands at Fifth and Mission Streets. It survived the 1906 earthquake and fire. It also guards a question that collectors still cannot answer.
What exactly sits inside that cornerstone?
More importantly, does it still contain the only 1870-S Liberty Seated Quarter ever struck?
A Mint Built for a Silver Flood
By 1870, San Francisco had outgrown its first Mint building. Gold Rush commerce had already transformed the city. Then the Comstock Lode added a new pressure. Western silver poured toward the coast, and the government needed a stronger, larger facility.
So, federal officials planned a new Mint at Fifth and Mission Streets. Work began in 1869. The structure took shape as a massive granite building, designed to project federal power in a young western city.
Then came the public ritual.
On May 25, 1870, Masonic officials, Mint personnel, soldiers, civic leaders, and spectators gathered for the cornerstone ceremony. Contemporary accounts described a large procession and a copper casket. That casket held documents, newspapers, postage stamps, and a set of United States coins.
At first, that sounds routine.
However, the coin set created the problem.
The Line That Changed Everything
Newspaper accounts and later Mint research point to a specific cornerstone inventory. The casket received one coin of each gold and silver denomination struck at the San Francisco Branch Mint in 1870.
That sentence matters.
The San Francisco Mint did not produce every denomination for normal commerce that year. Regular 1870-S issues included coins such as the dime, half dollar, gold dollar, quarter eagle, half eagle, eagle, and double eagle.
However, four denominations created the mystery:
- Liberty Seated Half Dime
- Liberty Seated Quarter
- Liberty Seated Dollar
- Indian Princess Three-Dollar Gold Coin
Official Mint reports did not list production for those four denominations at San Francisco in 1870.
Yet three of them exist outside the cornerstone story.
That means someone struck coins that the annual report did not record.
The Phantom Coins of 1870-S
The 1870-S Liberty Seated Dollar stands at the center of the mystery. PCGS lists 12 known survivors. Other researchers confirm fewer, depending on roster standards. Either way, the population remains tiny.
The finest known dollar carries a PCGS MS62 grade. It traces through the Col. E.H.R. Green and James A. Stack pedigrees. It sold in 2003 for $1,092,500. It remains the only verified Uncirculated example.
Most other 1870-S dollars show wear. That detail matters. These coins do not look like untouched presentation pieces. Instead, they look like coins that entered pockets, drawers, and circulation.
That leads to a striking possibility. Mint personnel may have struck a small number of extra dollars as souvenirs. Then recipients may have spent them, carried them, or ignored their importance.
One example entered public attention with the initials “FHI” scratched into the obverse. It appeared in a 1926 William Hesslein auction. Later, someone removed those initials through tooling. Researchers still have not identified “FHI.”
The initials remain a human fingerprint on a federal secret.
The Half Dime That Hid for 108 Years
The 1870-S Liberty Seated Half Dime adds another layer.
Collectors did not know it existed until 1978. That year, a single example surfaced in the Chicago-area coin trade after a small group of coins came into Orland Coin and Stamp Shop in Orland Park, Illinois.
The discovery stunned the hobby.
Today, the coin grades PCGS MS64 with CAC approval. Heritage Auctions sold it in January 2023 for $3,120,000.
So, the half dime confirms the larger pattern. The San Francisco Mint produced at least one unlisted 1870-S denomination outside normal circulation records.
The $3 Gold Coin and the Yellow Paper Clue
The 1870-S Three-Dollar Gold Coin gives the mystery its strongest written clue.
Only one example exists for collectors. The coin shows a unique, hand-engraved “S” mintmark. It also carries the mysterious number “893” engraved on the reverse. The piece later showed signs of jewelry use, which suggests someone treated it as a keepsake long before collectors understood its importance.
Its story became even more important because of a note.
When the coin entered numismatic channels in the early 20th century, it reportedly came with a handwritten statement from San Francisco Mint Chief Coiner Joseph B. Harmstead. The note said the coin duplicated the one under the San Francisco Mint cornerstone.
That line changes the entire story.
It suggests that Harmstead struck one $3 gold coin for the casket and that a second example left the Mint.
The known 1870-S $3 gold piece later passed through legendary collections, including Woodin, Newcomer, Green, Eliasberg, and Bass. In January 2023, Heritage sold the coin for $5,520,000.
A Die Crisis Before the Ceremony
The most dramatic part of the backstory involves dies.
Philadelphia supplied dies to branch mints. However, the San Francisco Mint faced a last-minute problem in May 1870. The letter “S” had not appeared on certain dies needed for the ceremony.
Mint correspondence shows that Superintendent O.H. LaGrange contacted Mint Director James Pollock. Philadelphia then sent replacement dies. However, time had almost run out.
Harmstead solved at least one problem by hand. He cut the “S” mintmark into a three-dollar die so the Mint could create the cornerstone coin.
The silver dollar posed another problem. Researchers Nancy Oliver, Richard Kelly, John Dannreuther, and Dick Osburn later connected the 1870-S dollar obverse to Carson City. Their research indicates that San Francisco likely borrowed an 1870 silver dollar obverse die from the newly opened Carson City Mint.
That detail gives the mystery a western twist.
A San Francisco ceremony may have depended on a Carson City die.
The Missing Quarter
The 1870-S Liberty Seated Quarter remains the ultimate ghost.
Documents indicate that quarter dies dated 1870 reached San Francisco. Research also supports the idea that a quarter belonged in the cornerstone set. Yet no 1870-S quarter has ever appeared in the numismatic market.
That absence makes the quarter more intriguing than the dollar, half dime, or $3 gold coin. Those coins escaped into private hands. The quarter did not.
Therefore, collectors face two possibilities.
The first possibility sounds simple. The Mint struck one quarter for the cornerstone, sealed it in the copper casket, and never made another.
The second possibility sounds darker. Someone removed the casket, or the quarter, during later building work, and the coin still waits in an unknown private holding.
No evidence proves the second scenario. However, the survival of the dollar, half dime, and $3 gold coin keeps the question alive.
If the cornerstone casket remains intact, it may contain the only 1870-S quarter in existence.
What the Legend Gets Wrong
This story also attracts exaggeration.
Some retellings include a possible 1870-S Shield nickel, two-cent piece, or three-cent coin. Those claims need caution.
The strongest documentary evidence centers on gold and silver denominations connected to the San Francisco Branch Mint. It does not establish that San Francisco struck base-metal minor coins for the casket.
So, the real mystery does not need extra mythology.
The confirmed puzzle already includes enough drama: three unlisted denominations with surviving examples, one unlisted quarter with no survivor, a hand-engraved mintmark, a possible Carson City die connection, and a sealed cornerstone that no one has recovered.
Were These Proofs?
Many collectors imagine the cornerstone coins as flawless Proofs. The evidence argues against that idea.
Known 1870-S dollars look like circulation strikes. The unique half dime shows no clear Proof format. The $3 gold piece carries a PCGS Specimen designation, but wear and jewelry damage complicate its original appearance.
Also, the records do not show a proofing charge for the cornerstone coinage.
Therefore, the best reading remains practical. The Mint created a ceremonial coin set. Some coins came from regular stock. Others required special, small-scale production because San Francisco did not strike those denominations for commerce that year.
The result still changed numismatic history.
The Copper Casket Still Waits
The Granite Lady survived the 1906 disaster. Mint employees helped protect the building during the fires that followed the earthquake. Later renovations changed parts of the structure. Those changes also complicated the search for the cornerstone.
Over the decades, historians and numismatists have tried to connect newspaper accounts, architectural plans, and surviving structural details. Still, no one has publicly recovered the casket.
That leaves the mystery frozen in granite.
Inside the lost casket may rest pristine examples of the 1870-S half dime, quarter, silver dollar, and $3 gold coin. Or the box may have vanished during later work. Until someone finds it, collectors can only follow the evidence left outside the walls.
And that evidence points to one extraordinary conclusion.
In 1870, the San Francisco Mint struck coins that official reports failed to record. Some escaped. Some became million-dollar trophies. One, the 1870-S quarter, may still sleep beneath a city block.
Why the 1870-S Mystery Still Matters
Great coin stories usually begin with rarity. This one begins with contradiction.
The records say no. The coins say yes.
That conflict makes the 1870-S San Francisco Mint story bigger than any single rarity. It connects federal bureaucracy, western expansion, Masonic ceremony, Comstock silver, Mint improvisation, and human souvenir-taking.
It also proves something collectors know well.
Sometimes the most important coins do not announce themselves at the Mint. They surface decades later, worn smooth by pockets, marked by initials, or rescued from a dealer’s box.
The 1870-S coins did more than escape the records.
They escaped history.
Now, every surviving example asks the same question: What else remains hidden inside the Granite Lady?
