Mumbai, July 21 -- Gold futures advanced toward the $4,100-per-ounce mark on Tuesday, while silver surged more than 4%, as investors weighed the prospects of renewed US-Iran peace talks against persistent geopolitical uncertainty. Although hopes of diplomatic engagement improved market sentiment, safe-haven demand remained firm after fresh warnings from President Donald Trump kept tensions in the Middle East elevated. Silver outperformed gold, rebounding sharply from recent lows as its dual role as both an industrial and monetary metal, coupled with ongoing global supply deficits and resilient industrial demand, strengthened investor interest. On the domestic front, MCX August gold futures gained 1% to Rs 1,42,765 per 10 grams, while Septem...