Oil posted its first weekly loss in two months as traders weighed heightened geopolitical tensions over Ukraine against the potential for Iranian barrels to be added to the market. Gold was little changed near an eight-month high as traders assessed heightened tensions over Ukraine ahead of an expected meeting next week between Russia and the US Nickel posted its highest closing price since 2011, with the Ukraine crisis adding to upside risks as buyers grapple with what Citigroup Inc. called an “extreme shortage” fueled by rising demand from the electric-vehicle sector.