* SPDR Gold Trust GLD, the world's largest gold-backed exchange-traded fund, said its holdings rose 0.3% to 1,045.78 tonnes on Monday from 1,042.87 tonnes on Friday. June 29 (Reuters) - Gold prices eased on Tuesday, as a firmer dollar made bullion expensive for holders of other currencies while concerns that the U.S. Federal Reserve will tighten its monetary policy sooner than expected also dented the metal's appeal. Gold is seen as a hedge against inflation, though a rate hike by the Fed will increase the opportunity cost of holding bullion and dull its appeal.