The world's oldest stone inscription of the 10 Commandments has been sold at auction in California for $850,000.

The two-foot-square slab of white marble is believed to have been carved in the late Roman period as early as AD 300 for a synagogue in western Israel, in what is now the modern city of Yavneh.

It is carved in a script used by the Samaritans derived from Hebrew and Aramaic and lists nine of the commandments from the book of Exodus, omitting "You shall not take the name of the Lord your God in vain" and adding one adopted by the Samaritans exhorting worshippers to "raise up a temple" on Mount Gerizim, near the West Bank city of Nablus.

The Samaritan sect was repressed by the Romans in the mid-400s and the synagogue may have been destroyed then or later, perhaps by the Muslims or the Crusaders.

It is officially designated one of Israel's "national treasures", but the Israel Antiquities Authority approved its export on the condition that it is displayed in a public museum.

Heritage Auctions director of ancient coins and antiquities David Michaels said: "The sale of this tablet does not mean it will be hidden away from the public. The new owner is under obligation to display the tablet for the benefit of the public."

The owner has chosen to remain anonymous. 

The tablet was the centerpiece of an offering of Biblical historic artifacts, all thoroughly researched and authenticated, and owned by the Living Torah Museum in Brooklyn, New York, according to ArtDaily.org.