Gold surged 1,310 rupees, its biggest single-day gain in two years, to 31,010 rupees per ten grams at Delhi's bullion market, today, on strong festive season demand by stockists, amid a sharp fall in the stock market. Silver zoomed 3,270 rupees, to 49,320 rupees per kilo, its biggest single day gain this year, on rising demand from industrial units and coin-makers.