The Red Riding Hood director is considering joining the British gangster movie, reports Screen Daily.
Set in the 1960s, the film will be the first to be produced by former City of London investment manager Nicola Horlick.
Details of Diamond are being kept under wraps, but it is expected to start shooting in 2013.
Joe Shrapnel and Anna Waterhouse (Frankie and Alice) are working on the script.
Hardwicke is best known as the director of the first Twilight film. Earlier this year, she was quoted as saying that she was not initially impressed by the script for the movie, but was won over when she read the book.
She is due to reunite with Thirteen star Evan Rachel Wood on erotic thriller Plush.
> Noomi Rapace joins film from 'Twilight' director Catherine Hardwicke