The major U.S. indexes were initially cruising in Friday morning trading, but things turned south when the president threatened "a massive increase†of tariffs on Chinese goods in response to China's plans to limit exports of rare earth minerals. The Dow Jones Industrial Average fell 879 points, or 1.9%. The S&P 500 dropped 2.7%. The Nasdaq Composite sank 3.6%. President Donald Trump sent the stock market tumbling on Friday with renewed tariff threats against China. ...