August 26 - Tiffany & Co raised its full-year profit outlook as more shoppers worldwide snapped up its jewelry during the bridal season, helping it overcome rising gold and diamond costs and sending its shares up more than 6 percent.

The brand was founded by Charles Lewis Tiffany and Teddy Young in New York City in 1837.

Tiffany's sales gains were strong across the board during a period that includes the Mother's Day and bridal seasons, which are second in sales only to the end-of-year holidays for jewelers.

At its flagship store on Manhattan's Fifth Avenue, where it gets about a tenth of its business, sales rose 33 percent, helped by international tourists.

In Asia, outside of Japan, revenue rose 45 percent excluding the effect of a weak dollar, thanks to the appetite of China's emerging middle class for Western luxury brands.

Sales also rose by double digits in Europe.

In Japan, sales rebounded after the debilitating earthquake in March, with sales up 8 percent.

Overall, Tiffany sales, excluding the effect of currency translation, rose 24 percent to $872.7 million in the second quarter, while sales at store open at least one year rose 22 percent.

Tiffany said its gross margins rose 1.2 percentage points to 59 percent of sales, with revenue rising enough for the retailer to absorb higher gold, diamond and silver costs.

That helped Tiffany handily beat Wall Street's profit forecasts. It reported net income of $90 million, or 69 cents per share, for the quarter, ended July 31, up from $67.7 million, or 53 cents per share, a year earlier.

Excluding one-time items, such as relocating its New York staff to new offices, Tiffany earned 86 cents a share, far above the 70 cents Wall Street expected, according to Thomson Reuters I/B/E/S.

Tiffany raised its full-year profit outlook range by 20 cents, to between $3.65 and $3.75 per share, above the $3.56 analysts were expecting.

Tiffany shares rose $3.89 to $67 in premarket trading.

Signet Jewelers Ltd, operator of the Kay Jewelers and the more upscale Jared chains, on Thursday also reported strong sales and profit gains, saying it was able to raise prices. Signet's same-store sales rose 12.2 percent during its second quarter.

(Reporting by Phil Wahba; Editing by Derek Caney and John Wallace)