Gold prices rallied by Rs 630 to a lifetime high of Rs 82,700 per 10 grams in the national capital on Wednesday following persistent buying by jewellers and retailers amid strong global trends, according to the All India Sarafa Association.Rallying for the sixth straight session, gold of 99.5 per cent purity appreciated by Rs 630 to hit a lifetime high of Rs 82,330 per 10 grams.