Gold plunged 625 rupees, to 31,700 rupees per ten gram at Delhi's bullion market, today, on sustained selling by stockists, triggered by a weak global trend. Silver tumbled 1,710 rupees, to 54,000 rupees per kilo, on reduced offtake by jewellers and industrial units. Silver coins dropped 1,000 rupees, to 88,000 rupees for buying 100 pieces. Overseas, gold fell 0.4 per cent, to 1,403 dollars an ounce. Silver dropped 0.6 per cent, to 23.73 dollars an ounce.