This study places the micro-level patterns and structures of the trade in ‘coltan’ – a form of tantalum ore – in the context of the war economy in the eastern Democratic Republic of Congo (DRC). Drawing on field research, it tracks a cycle of boom and bust in the world price of tantalum. Locally, the boom – a ten-fold price increase – incited ‘coltan fever’, an exodus from agriculture into mining in rural areas of the eastern Kivu provinces and the ‘dollarisation’ of rural and urban economies. The bust – a ten-fold price crash – did not cause the trade to cease but to consolidate, further increasing the domination of war entrepreneurs. The present war in the DRC did not begin with explicitly economic objectives. Rather, as the war reached a stalemate nationally, so belligerents turned inwards to the territory they control, capitalising – personally as well as collectively – on the rich resources available. Coltan both finances violence and provides an incentive for it. However, mining has also become a major survival mechanism for people at the grassroots. This, together with the convoluted nature of the coltan commodity chain at its upper levels, means that a global boycott is both unwise and difficult to implement.