The "Heart of the Ocean" was never found because it was only a fictional piece of jewelry featured in the James Cameron film, "Titanic." The British jewelers Asprey & Garrad were consigned to fashion the blue diamond necklace for the movie.
In one of the most prominent scenes in the film, the main character Rose Dewitt Bukater, played by Kate Winslet, wears the necklace while Jack Dawson, portrayed by Leonardo DiCaprio, paints her in the nude. Rose later finds it inside the coat she was wearing after she is saved from the sinking Titanic.
Other replicas of the "Heart of the Ocean" were made by Harry Winston, Noveau Treasures and the J. Peterman Company.