Gold inched down on Tuesday after optimism about Spain's bank bailout quickly gave way to renewed worries about the euro zone debt crisis ahead of a string of key events later this month. Spot gold edged down 0.3 percent to $1,589.50 an ounce by 0651 GMT. US gold futures for August delivery lost 0.4 percent to $1,590.70. Asia's physical market activities were in slow motion, as prices have hovered around $1,600 so far this week, dealers said.