LONDON — A missing piece of Stonehenge has been returned to Britain 60 years after it was taken, and the piece is likely to provide clues to the origins of the prehistoric monument, said English Heritage, the organization that takes care of the site, on Wednesday.

The missing stone — roughly the size and shape of a broomstick — was taken by a Briton, Robert Phillips, who worked with a diamond-cutting business at the time and emigrated to the United States around three decades ago.

Mr. Phillips took part in repair works at Stonehenge in 1958 to raise one of the trilithons, the iconic three-piece standing stones, that had fallen to the ground. The work included drilling ring-shaped holes into the stone, and it produced three-foot cylinders.

He retired to Aventura, Fla., north of Miami, according to the BBC, and kept the polished-looking stone in his office for decades. But on the eve of his 90th birthday last year, he decided to return the piece to England.