Potentially, there is no more valuable U.S. coin than the 1870-S half dime. It could also be said that when it comes to auction prices, there has been no more disappointing coin than the 1870-S half dime.
In 1870, San Francisco was laying the cornerstone for a new mint facility. The original facility was small, loud and generally unpleasant, and by 1870 it was finally time to begin construction on a new one.
To mark the events, it was decided to put a San Francisco coin of all denominations in the cornerstone. That, however, presented a problem since that year San Francisco was making no half dimes, quarters, silver dollars or $3 gold coins. Officials decided to make examples of each to put in the cornerstone. In the case of the silver dollar, some extra examples were made, allegedly to be presented to special guests. In the case of the other denominations, the belief was that just a single coin of each was made.
For years little was thought of the coins from that cornerstone, but then a $3 gold 1870-S appeared on the market. However, it was almost seen as a fluke at the time and not much attention was paid.
Decades later in the 1970s, major Chicago dealer RARCOA stunned the hobby with the announcement of the discovery of an 1870-S half dime. Once authenticated, everyone was equally confused as to how much it was worth.
In his book, American Coin Treasures and Hoards, Q. David Bowers tells the story of what happened next, which was that Michigan coin dealer John Abbott agreed to buy the 1870-S for $25,000 more than the price realized by the 1804 dollar in the Garrett Collection. As a unique coin, the price seemed fair. In theory, the 1870-S was much tougher than the 1804, which has eight known Class I examples.
No on counted on the fact that the 1804 sale would be one of those moments where a coin simply exceeds the price expected. It brought $400,000, making the 1870-S a $425,000 coin. It was the height of the market. There was nowhere to go in price but down, and the next time the 1870-S was offered the price was just $176,000. The 1870-S was a classic case of being bought at the top and sold at the bottom. It later sold for or $253,000.
There continues to be stories about the 1870-S in private sales. The latest pegs it at $1.4 million. However, until the 1870-S reaches auction again, we won’t have a real public test of its potential.