Gold surged by Rs 171 to Rs 48,642 per 10 grams in the local market on Wednesday as its international price improved to $1,641 an ounce, market sources said. According to Karachi Sarafa Association official, gold in tola (11.664 grams) price also increased by Rs 200 to Rs 56,750. Silver closed lower at Rs 882.85 per 10 grams.