Gold prices dropped to $1,608.90, a six-month low, Friday on the New York Mercantile Exchange as the the dollar strengthened against the euro. On the Comex listing, February gold fell $25.90 or 1.6 percent to finish at $1,608.90 per troy ounce. Against the dollar, the euro held steady at $1.336. The dollar rose to 93.51 yen from 92.87 yen. The dollar index rose 0.1 percent to 80.47 on the International Exchange. The British pound fell to $1.5516 from $1.5494 The U.S. dollar rose to 1.0064 Canadian dollars from 1.001 Canadian.