Gold prices tumbled 750 rupees, to an over 15-month low of 27,600 rupees per ten grams at Delhi's bullion market, today, on heavy selling by stockists, triggered by a sell-off in the global markets. Today's fall comes after gold had posted its biggest single-day loss of 1,250 rupees, on Saturay. Silver plunged 2,100 rupees, to 48,000 rupees per kilo. Silver coins plummeted 3,000 rupees, to 74,000 rupees for buying 100 pieces.In London, gold sank 91 dollars, or 6.1 per cent, to a 2 year low of 1,386 dollars an ounce, amid concerns that the 12-year bull run in the precious metal has come to an end. Gold plunged as investors sold off commodities for a second day, today, worried that central banks will pull the plug on stimulus, and as disappointing Chinese data signaled a setback for global economic recovery. Silver plummeted 10.5 per cent, to 23.13 dollars an ounce.