A 1,500-year-old stone tablet with the earliest known chiselled inscription of the Ten Commandments was sold at a US auction for $850,000 on Wednesday.

The two-foot (61 cm) square slab of white marble that weighs about 115 pounds (50 kg) was sold in Beverly Hills, California, by Dallas-based Heritage Auctions to a buyer who not to be immediately identified.

The tablet was put up for sale by Rabbi Shaul Deutsch, founder of the Living Torah Museum, in Brooklyn, New York, with the stipulation that the buyer must put it on public display, the auction house said.

The tablet is chiselled with 20 lines of Samaritan script with principles that are fundamental to Judaism and Christianity.

The inscription lists nine of the 10 commandments in the Book of Exodus, omitting "Thou shalt not take the name of the Lord thy God in vain" and replacing it with a rule for Samaritan worshippers, the auction house said.