I could swear he says in the film, that he is from Zimbabwe!
Blood Diamond's Leonardo DiCaprio
Set against the backdrop of the chaos and civil war that enveloped 1990s Sierra Leone, “Blood Diamond” is the story of Danny Archer (Leonardo DiCaprio), an ex-mercenary from Zimbabwe
, and Solomon Vandy (Djimon Hounsou), a Mende fisherman. Both men are African, but their histories and their circumstances are as different as any can be until their fates become joined in a common quest to recover a rare pink diamond, the kind of stone that can transform a life--or end it. The juxtaposition of one man obsessed with finding a valuable diamond with another man risking his life to find his son is the beating heart of this film.
Full Interview: http://www.emanuellevy.com/article.php?articleID=3833
Some places it says he is South African and some say he is Zimbabwean. But I think during the film he says he is from Zimbabwe, so listen out for it and let us know!