DIAMOND conglomerate De Beers is concerned that the European Commission will thwart its plans to market diamonds bearing the De Beers brand name. London’s Financial Times reports on Tuesday that De Beers’ hopes of selling branded diamonds with its name and a number etched by laser may run foul of European competition law. A decision not to proceed with a worldwide marketing programme of branded diamonds would upset the group, which hopes to sell its gems at a premium to other suppliers. That premium would put other producers under pressure to join the De Beers cartel, the report said.