Are some of our elegant symbols of modernity — smartphones, laptops and digital cameras — fueling slaughter and rape in Congo? The New York Times on the campaign for “clean” minerals. Nicholas D. Kristof says he’s never reported on a war more barbaric than in Congo, where warlords finance their predations in part through the sale of mineral ore containing tantalum, tungsten, tin and gold. Tantalum from Congo, for example, is used to make electrical capacitors for phones, computers and gaming devices. Now there’s a grass-roots movement pressuring companies to keep “conflict minerals” out of high-tech supply chains.