Riding high on a firm trend in the global markets, gold rose 160 rupees, to a fresh all-time high of 26,840 rupees per ten grams at Delhi's bullion market on Thursday following sustained buying by investors and stockists. Silver gained 600 rupees, to 61,300 rupees per kilo.In the overseas markets, gold advanced for the fourth straight day, rising to 1,796 dollars an ounce, amid worries about a global economic slowdown.