* MSCI world equity index slips as stocks turn south
* Index set for biggest quarterly gain since 1988 launch
* Oil slides on day but posts best qtly gain in 19 years
* Declining U.S. consumer confidence overshadows optimism (Adds close of U.S. markets)
By Herbert Lash
NEW YORK, June 30 (Reuters) - Global stocks fell on Tuesday after a decline in U.S. consumer confidence cast doubt about the strength of a recovery that set MSCI's world equity index on course for its best quarterly gain since its 1988 inception.
In a sign the worst of the credit crisis and world recession may be passing, crude oil prices posted their strongest quarter in 19 years, despite a 3 percent slide on Tuesday spurred by a weaker dollar and the U.S. confidence data.
The Conference Board's index of consumer attitudes fell unexpectedly in June to 49.3 from a downwardly revised 54.8 in May, helping turn European stocks lower and halt an early sell-off in the U.S. currency.
The data also pushed U.S. stocks lower, but the benchmark Standard & Poor's 500 Index posted its best quarterly performance since the fourth quarter of 1998, rising 15.2 percent from April through June
It was the first positive quarterly performance of the S&P 500 since the third quarter of 2007. The CBOE Volatility Index <.VIX>, a gauge of investor fear, had its biggest quarterly drop since 1998, down nearly 40 percent.
The S&P 500 is up 35.9 percent since sliding to a 12-year closing low on March 9.
Investors took heart in recent data that showed a freeing up of credit markets, a cyclical, inventory-driven rebound in manufacturing, an easing of the housing market slump and a rebound in business and consumer confidence.
Authorities have gained traction against the downturn via extraordinary monetary policies, with official interest rates near zero and long-term borrowing rates capped by measures known as quantitative easing.
Still, investors are questioning whether the "green shoots" that Chairman Ben Bernanke of the Federal Reserve has used to describe an economy on the mend are actually flourishing.
A raft of data -- Japan's jobless rate rose 5.2 percent in May, German unemployment rose in June and loans to euro zone businesses and households grew at the slowest pace on record in May -- added to the gloomy mood sparked by the consumer data.
"For the market to go much higher, you are going to have to see some real hard evidence of some of these things that are being anticipated by the market start to come to fruition," said Tom Alexander, head of Alexander Trading in Savannah, Georgia.
The Dow Jones industrial average <
> closed down 82.38 points, or 0.97 percent, to 8,447.00. The Standard & Poor's 500 Index <.SPX> dropped 7.91 points, or 0.85 percent, to 919.32. The Nasdaq Composite Index < > shed 9.02 points, or 0.49 percent, to 1,835.04.MSCI's all-country world index <.MIWD00000PUS> fell 0.66 percent, on track to its best quarterly performance in more than two decades. The index closes at 9 p.m.
David Resler, chief economist at Nomura Securities International in New York, said prices may have gotten a bit ahead of events in the last few days.
"This is a wake-up call for the stock market that the economic recoveries typically move in fits and starts, and this kind of (move) in consumer confidence is a revelation that it is not all clear sailing from here," Resler said.
European shares fell on Tuesday, with the FTSEurofirst 300 <
> index of top European shares off 1.1 percent to close at 850.17. The index gained 15.9 percent in the quarter.The simultaneous end to the month, quarter and the half-year led to increased volatility in foreign exchange trading, exacerbating intra-day moves in currencies.
U.S. Treasury prices softened with benchmark yields posting their worst six-month performance in more than a decade as the confidence data offset signs of a better-than-expected housing market.
The benchmark 10-year U.S. Treasury note <US10YT=RR> fell 15/32 in price to yield 3.54 percent. The 2-year U.S. Treasury note <US2YT=RR> fell 1/32 in price to yield 1.12 percent.
The dollar rose against a basket of major currencies, with the U.S. Dollar Index <.DXY> up 0.44 percent at 80.186. Against the yen, the dollar <JPY=> was up 0.20 percent at 96.32.
The euro <EUR=> was down 0.35 percent at $1.4026.
Oil prices rose almost 43 percent in the second quarter, the biggest quarterly percentage gain since 1990.
U.S. crude <CLc1> settled down $1.60 at $69.89 a barrel, after earlier rising to an eight-month high of $73.38. London Brent <LCOc1> gave up $1.69 to settle at $69.30 a barrel.
Copper erased earlier gains to close lower, under pressure from a firmer dollar, quarter-end positioning and growing perceptions that prices have risen too far in the face of a poor fundamental backdrop.
Gold futures tumbled below $930 an ounce as a stronger dollar prompted broad-based selling across the commodities sector.
U.S. August futures <GCQ9> settled down $13.30 at $927.40 in New York.
Asian stocks rose on the last day of a torrid quarter, as investors added to trades based on an economic rebound. Japan's Nikkei share average <
> finished 1.8 percent higher. (Reporting by Rodrigo Campos, Edward Krudy, Vivianne Rodrigues and Chris Reese in New York; Brian Gorman, Ian Chua, Joe Brock and Nick Vinocur in London; writing by Herbert Lash; Editing by Leslie Adler)