The tablet weighs about 115 pounds and is inscribed in an early Hebrew script called Samaritan.
It likely adorned the entrance of a synagogue that was destroyed by the Romans between A.D. 400 and 600, or by the Crusaders in the 11th century, said David Michaels, Heritage Auctions director of ancient coins and antiquities.
The auction house said the Israeli Antiquities Authorities approved export of the piece to the United States in 2005. The only condition was that it must be displayed in a public museum.
"The sale of this tablet does not mean it will be hidden away from the public," Michaels said. "The new owner is under obligation to display the tablet for the benefit of the public."
The tablet lists nine of the 10 commonly known commandments, leaving out "Thou shalt not take the name of the Lord thy God in vain" (King James translation), and adding one often employed by the Samaritan sect, encouraging worshippers to "raise up a temple" on Mount Gerizim, the holy mountain of the Samaritans, according to Heritage Auctions.