WASHINGTON - With Europeans and Asians buying fewer $65,000 diamond necklaces and $10,000 amethyst earrings, Tiffany & Co may be in for a less-than-glittering 2012.

No US luxury merchant is more exposed internationally. The world's second-largest jeweler generates almost half its sales outside of the Americas, up from 38 percent in 2006, according to data compiled by Bloomberg.

Tiffany's foreign sales are concentrated in Europe, which is facing a sovereign debt crisis, and Asia, where China's growth is slowing.

"It's better to be a little more conservative for those other parts of the world," said David Schick, an analyst with Stifel Nicolaus & Co in Baltimore. "You are seeing more volatility in the financial markets. It's not confidence-inspiring for bigger-ticket spending. That tells you not to expect too much in the top line for Tiffany."

Tiffany's revenue was $3.09 billion in 2010 and is estimated at $3.68 billion for 2011, according to the average of 20 analysts surveyed by Bloomberg.

Analysts are scaling back their profit forecasts, and Tiffany shares have slid 21 percent since their 12-month high on July 19.

Over the same period, Coach Inc has fallen 9.4 percent, Ralph Lauren Corp is little changed and the Standard & Poor's 500 Index is down 5.2 percent.

Slowing sales growth in Asia and Europe may have more of an effect on Tiffany's profits than revenue, Schick said. The jeweler's international stores are more profitable because they are smaller and located in densely populated areas and so have greater sales for each square foot, he said.

Tiffany's operating margin in the Asia-Pacific region was 28 percent in the most recent quarter and 21 percent in Europe, compared with 17 percent in the Americas. That margin is its operating earnings as a percentage of revenue.

In the past 15 years it has unveiled about 80 foreign locations, more than the 60 or so it has opened in the US.

With its signature six-pronged setting, Tiffany helped get Asians interested in diamond engagement rings. In Europe, the company positioned itself as a luxury brand with a wider range of prices than its rivals. Customers could find silver jewelry selling for the equivalent of hundreds of dollars alongside pieces in the millions.

As of Oct 31, Tiffany had 55 stores in Asia excluding Japan, with 32 of those in China. It also had 32 in Europe, out of a total 243.

In the most recent quarter, sales in the Asia-Pacific region accounted for 22 percent of total revenue of $821.8 million. Europe accounted for 11 percent.

During the summer, Europe's sovereign debt crisis began to spread around the globe.

The eurozone is already in a "mild recession", with GDP rising just 0.2 percent in 2012, the Organization for Economic Cooperation and Development (OECD) in Paris said on Nov 28.

European luxury sales will grow by 5 percent in 2012 after two years of growth exceeding 10 percent, according to a December report from CA Chevreux in Paris.

China will expand by 8.5 percent this year, the lowest pace in 11 years, the OECD forecast. Luxury-sales growth will ease in 2012 from a forecast of at least 20 percent in 2011, according to the Royal Bank of Scotland.

On Nov 29, during its most recent earnings conference call, Tiffany cited "recent weakness" in Europe. Mark Aaron, a Tiffany spokesman, declined to comment for this story.

Bloomberg News