By Aarthi Sivaraman

Tiffany's U.S. sales have been weak recently as consumers cut back on discretionary purchases, though its higher-income clientele tend to be less affected by economic concerns than people who frequent hard-hit jewelers such as Zale, Finlay Enterprises and Signet Group .

But Tiffany, whose shares rose nearly 7 percent in pre-market trading, said on Thursday it expects its U.S. same-store sales to return to growth in the fourth quarter, which includes the key holiday shopping season.

Net profit at Tiffany nearly doubled to $80.8 million, or 63 cents per share, in its fiscal second quarter, ended July 31, compared with $40.5 million, or 29 cents per share, a year earlier.

Analysts, on average, expected a profit of 55 cents per share, according to Reuters Estimates.

Tiffany's sales rose 11 percent to $732.4 million.

It raised its full-year earnings outlook, to a range of $2.82 to $2.92 per share. Previously, it had forecast per-share earnings of $2.80 to $2.90.

WEAKNESS SALES AT ZALE

Dallas-based Zale has suffered in recent months as even its most avid shoppers resist buying jewelry due to rising prices for necessities like food and fuel.

The company posted a quarterly loss of $4.9 million, or 15 cents per share, compared with a profit of $1.5 million or 3 cents per share a year earlier.

Zale's loss of 48 cents a share, excluding certain benefits, was less than the 57 cents per share loss analysts expected, according to Reuters Estimates.

Zale had expected margins to be hurt in the quarter as it aggressively marked down jewelry to clear out inventory.

Total sales at Zale rose 6.1 percent to $456.2 million.

The company expects to earn $1.10 per share to $1.25 per share for the full-year ending in July 2009. Adjusted for total warranty sales, Zale expects to earn $2.35 per share to $2.50 per share.

(Editing by Steve Orlofsky and Derek Caney)