Although mint records do not indicate that any were produced, nine examples of the 1870-S Seated Liberty Dollar (Buy on eBay) are known to exist. The original mintage is estimated to be 12 pieces, making it the rarest regular issue of the series and one of the rarest silver dollars of all time.
It is believed that the 1870-S Silver Dollars were struck for the purpose of creating a time capsule for the San Francisco Mint. Plans had been made to include a complete set of denominations when the cornerstone of the new building was laid on May 25, 1870. Presumably, more than one example of the silver dollar was struck, since they would make suitable keepsakes from the ground breaking ceremony.
Of the nine examples currently confirmed to exist, all but one show signs of circulation or damage. The finest known and single uncirculated specimen is graded PCGS MS-62 and has sold for more than $1 million. Other circulated examples have commanded strong six-figure prices.