Gold jumped on Friday as investors took refuge from equity and debt markets on mounting concerns about the threat of contagion from the euro zone crisis and as worries about a slowdown in U.S. growth fuelled a pullback in risky assets. Spot gold hit a session high of US$1,669.60 a troy ounce. It was bid at $1,666.70 an ounce at 1109 GMT from $1,647.90 an ounce late in New York on Thursday, up 1.1...