The current coin is a different 1870-S three dollar gold coin. This should cause us to pause -- so this coin is perhaps not unique. The mintmark looks different from its sister. Does this mean that a second die was made just to produce a single coin? Or is this story quickly losing its credibility.
The coin was apparently discovered embedded in a souvenir book in San Francisco. How and why did it get there? This remains shrouded in mystery.
The auction company expected the coin to fetch about four million dollars. And yet the coins has not been authenticated by any service. Again, this should cause us to pause. The auctioneer encouraged people to view the coin in person and to bring experts. But who is the expert who can authenticate a coin with a unique mintmark that was struck from a once-used die?
The coin has apparently been suddenly removed from the auction. Either way, I encourage my millionaire friends to exercise caution.