In the movie Blood Diamond, Leonardo DiCarpio wears a Breitling Chrono Avenger watch with solid titanium 44mm case on a brown calf leather strap.
The exact model watch worn by Leonardo DiCaprio is the Breitling Chronograph Avenger Titanium Automatic E13360 44 mm.
The dial has a date window at 3 o'clock and Arabic numerals.
In some pictures, the dial looks blue, but this blue reflection from the sapphire crystal could be just the anti-reflective coating of the crystal, which produces a bluish hue when viewed at certain angles, as the the image on the left of a Chrono Avenger illustrates. It is not confirmed if the watch in the movie has a black or blue dial, but it's most likely the black dial.
The exact same Breitling Chrono Avenger as seen in Blood Diamond can be found on eBay for around $2000 - $3500.
Alternative model
Since the old Breitling Avenger from the time of the movie is hard to find, you could consider the beautiful, more modern and bigger GMT version of the Breitling Chrono Avenger, currently for sale at Bob's Watches for $4,795 or at JomaShop for only $2,995 (on sale), or with a blue dial for $3,295.
The Chrono Avenger is also available in other editions at JomaShop, see all listings here.