GLOBAL MARKETS-U.S. stocks slip on earnings; US dollar index at 7-month high

* U.S. stocks off on earnings outlook; UK shares higher

* U.S. dollar index at 7-month high on likely Fed rate rise

* Oil prices down on higher dollar, but metals rise (Changes dateline to New York; adds Wall Street open)

NEW YORK, Oct 25 (Reuters) - U.S. stocks slipped on disappointing earnings reports on Tuesday, while U.K shares rose helped by mining firms, and crude oil prices fell as the U.S. dollar hit a seven month high.

Nine of the eleven sectors in the benchmark U.S. S&P 500 stock index were negative, after poor earnings forecasts from some of the largest companies.

General Motors Co shares fell more than 4.7 percent, despite better-than-expected third-quarter earnings, amid fears a slowdown in U.S. vehicle sales and a rising U.S. dollar will undercut international profits.

Caterpillar Inc also reported a sharply lower quarterly profit on slow sales, driving its stock price down 1.4 percent.

Manufacturer 3M fell 3.0 percent to $165.87 after the maker of Scotch tape and Post-it notes trimmed its full-year revenue and earnings forecasts for the second time.

“We’ve had some mixed earnings today and the market right now is digesting earnings and positioning itself ahead of the Fed meeting next week,” said Jeff Zipper, managing director for investments at Private Client Reserve at U.S. Bank in Palm Beach, Florida..

Another third of the S&P 500 index stocks are scheduled to report earnings later this week, including heavyweights Apple , Alphabet, Amazon and Boeing.

The Dow Jones industrial average fell 40.27 points, or 0.22 percent, to 18,182.76, the S&P 500 lost 5.72 points, or 0.27 percent, to 2,145.61 and the Nasdaq Composite dropped 20.81 points, or 0.39 percent, to 5,289.02..

It was a different picture in Europe, where mining companies rose 2.9 percent, lifted in part by Anglo American . The mining company rose 4.0 percent after its production update. Anglo is the top performing stock on Europe’s STOXX 600 this year.

The U.K.’s FTSE 100 Index extended gains, rising 0.34 percent as sterling dipped slightly.

Germany’s Dax turned slightly lower after hitting its highest level of the year. The closely-watched Ifo survey had beat expectations a day after purchasing manager numbers had done the same.

Metal prices also surged, with zinc up 1.88 percent at $2,355, from an earlier three-week high of $2,376. It is up nearly 60 percent from January lows on worries about shortages.

“We are seeing a pick-up of economic activity against the backdrop of only one central bank - the Fed - that is likely to tighten policy and that is supporting asset markets,” said CMC Markets senior analyst Michael Hewson.

In Asia, Japan’s Nikkei rose 0.7 percent to close at a six-month high as a softening yen burnished the outlook for the country’s exporters. Australian stocks added 0.6 percent and Taiwan 0.7 percent.

Other commodity prices slipped though as many are priced in U.S. dollars and the greenback rose to a seven month high on an index of major currencies.

The U.S. dollar is benefiting from expectations of a Federal Reserve interest rate rise before year end. Traders saw a more than 78 percent chance the Fed will raise rates in December, up from a 74 percent chance Monday, according to data from CME Group’s FedWatch program.

China’s yuan hit its lowest against the dollar since offshore trading was introduced in 2010 of 6.7882 yuan per dollar. The People’s Bank of China set the midpoint rate at 6.7744 per dollar prior to market open, weaker than the previous fix 6.7690.

“We approach the prospect that the Fed will raise rates in December, especially if we have a status quo result in the U.S. election, which seems more likely,” said Thierry Albert Wizman, global interest rates and currencies strategist at Macquarie Ltd in New York. “This is helping the dollar.”

Oil prices were lower with U.S. crude breaking below $50 per barrel ahead of weekly data that could show a rise in domestic inventories.

Brent was 56 cents, or about 1 percent, lower at $50.90 per barrel at 11:30 a.m. ET (1530 GMT), while U.S. crude dropped by 42 cents to $50.10.

Additional reporting by Marc Jones and Pratima Desai in London, Tanya Agrawal in Bengaluru; editing by Clive McKeef