The Diamond is a 1954 British film noir crime film directed by Montgomery Tully/Dennis O'Keefe (see Production section, below) and starring Dennis O'Keefe, Margaret Sheridan and Philip Friend. It is based on the 1952 novel Rich Is the Treasure by Maurice Procter. It was released by United Artists in Britain and in America, where it was known as The Diamond Wizard.

It is notable for being Britain's first 3D film, though according to the British Film Institute, it was shown in 3D only once, on 13 September 2006 in Hollywood. Despite the 2006 showing the film was listed on the BFI 75 Most Wanted list of lost films. The 2D film, however, is not lost and can be viewed on Amazon Prime while the restored 3D version was released on Blu-Ray in November 2022.