SHANGHAI- China stocks stumbled on Friday as a growing war of words between the United States and North Korea combined with profit-taking in cyclical sectors to send shares down for the week.The blue-chip CSI300 index fell 1.8 percent, to 3,647.35 points. For the week, the CSI300 ended down 1.6 percent.China CSI300 stock index futures for August fell 2.0 percent, to 3,627.8, 20.16 points below the current value of the underlying index.The Shanghai Composite Index lost 1.6 percent to 3,209.80 points, its sharpest daily drop this year. The index fell 1.6 percent for the week.The materials sub-index, which had risen more than 16 percent since the beginning of the third quarter in July, fell 5.0 percent as investors chose to book profits amid rising geopolitical worries.Xiamen Tungsten Co Ltd fell 10 percent, bringing its weekly loss to 3.2 percent. The company's shares remain up more than 40 percent since the beginning of the quarter.Jiangxi Copper Co Ltd dropped 9.5 percent on Friday, racking up a weekly loss of 9.4 percent.The losses were not confined to materials. Kweichow Moutai , which had risen to a record-high close of 491.63 yuan on Thursday, gave up 1.5 percent. Fellow baijiu-maker Wuliangye Yibin dropped 2.8 percent.The overall consumer staples sub-index fell 9.5 percent on Friday. For the week, it was 9.4 percent lower.