ColtanA decade ago no one except geologists had heard of tantalum or 'coltan' an obscure mineral that is an essential ingredient in mobile phones and laptops. Then, in 2000, reports began to leak out of Congo: of mines deep in the jungle where coltan was extracted in brutal conditions watched over by warlords. The United Nations sent a team to investigate, and its expos of the relationship between violence and the exploitation of coltan and other natural