From her shop on the busy road through downtown Pailin, Sami Chanry watched the cars pass and kick up dust.

"I've done this business since 1970," she said. "I'd sift and sell and shape the stones, and then we would have a lot of gems. But during the past seven or eight years, the gems have become rare. [Those who seek them] must go far from town to find the gems, like into the Trop Mountains, the Bor Tang Su River and O'tang Mountain."

Pailin was known as "the city of gems," and its precious stones once funded, in part, the Khmer Rouge resistance to government forces. After the collapse of the regime in 1996, large Thai companies came from across the border, with huge shaker machines and excavators. And now the gem mining industry in Pailin is nearly finished.

A gem cutter not far from Sami Chanry's shop said he now received only the smallest gems to shape. One of the reasons that the precious stones have become rare is that the giant machines came in after the fall of the Khmer Rouge, he said.

Pailin Governor Y Chien said that the government doesn't want to give the license to gem mining companies, or allow them to mine state land, but they are still in Pailin, so the gems must be also.

More than 50,000 people live around the former Khmer Rouge stronghold, and many of them, in the 1960s and 1970s, supported themselves through the search for precious stones.

Today, the active businesses in town center around agriculture, hotels, and the border casinos that employ 3,000 people.

Em Reuy is not one of them. She sifts for gems in a river near town.

"Now, I can find less and less," she said recently, just finishing her work for the afternoon. "Sometimes I find nothing all day, or I have to take four or five days and I find two or three gems, and I can sell for 400 or 500 baht (about $10 to $12). Two years ago, gems became rare."

In Pailin, this means the poor families who once sought gems for direct sale in town have sought other work.

Em Reuy said some of the miners have turned to work on plantations. Instead of combing the rivers and mountains for stones, they now cut sugarcane, or harvest corn, or grow rice.

The poorest of villagers cannot change their business, Em Reuy said. They are forced to continue their search for gems.