Continuing its losing streak for the fifth straight day, silver prices tumbled a whopping 4,400 rupees, to 59,200 rupees per kilo at Delhi's bullion market, today, on heavy selling by speculators, amid a weak global trend. Gold lost 310 rupees, to 22,345 rupees per ten grams. In the global markets, gold fell 3.20 dollars, to 1,513 dollars an ounce. Silver lost 1.7 per cent, to 38.73 dollars an ounce. Silver plunged after futures exchange organiser, CME Group announced its fourth and fifth increases in margin requirements since April 26.