Mannukkul Vairam (English : Diamond inside sand) is a 1986 Indian Tamil film directed by Manoj Kumar and produced by Motherland Pictures. The film features Sivaji Ganesan, Sujatha, Rajesh and Murali in lead roles. The film, had musical score by Devendran.
Manojkumar, brother-in-law of director Bharathiraja made his directorial debut with this film. Producer Kovaithambi was impressed with the story narrated by Manojkumar and he immediately narrated the story to Sivaji Ganesan who agreed to act in the film.
Kovaithambi said that film ran for 50 days, though it was not that successful but the film gave him satisfaction of making a film with Sivaji Ganesan.