SPENCER, Idaho (AP) -- From Interstate 15, the tiny town passes in a moment, just a blip of brown buildings in the desert. But inside the local stores is a treasure trove. The fire of opals erupts from jewelry cases lining the walls.

Spencer, population 38, holds one of the largest opal deposits in the United States and is home to rare star opals. Though white is the most common color worldwide, Spencer miners find rarer blue, pink or red gems.

``Our customers are generally jewelers and distributors,'' said Bob Thompson, who owns Opal Mountain Mines with his wife, Susan. ``In the winters we close up and go to California because you can't mine when the ground is covered in snow. But people do stop in from the highway, and they're generally surprised at all we have.''

All they have includes opal jewelry and loose stones, traditional fire opals and opals that have rarer patterns that look like peacock feathers, harlequin squares or stars.

One wall is lined with mason jars, filled with gray, broken rocks. The rocks are veined with flaky layers of raw opal, the same way it comes out of the mine.

``This is the only place in America where you can sell canned opals, you've got so much,'' Susan Thompson said.

Two lost deer hunters from Rexburg discovered opals in the area in 1948 as they wandered about 70 miles from the west edge of Yellowstone National Park. The first claim was filed in 1952, and now the town is dominated by four commercial opal companies.

Dennis and Jackie Hooper are the newcomers. Dennis Hooper, a longtime rockhound, mines his claim to supply his store, High Country Opal. Brightly painted signs aimed at the highway proclaim the store is open 365 days a year -- an idea his neighbors laughed at.

``They said there's no way I'd stay open every single day of the year,'' Dennis Hooper said. ``But I am. In wintertime, this is the only restroom open in 100 miles.''

Travelers who dash in for a rest stop pause when they see the gems, he said. They generally leave sporting an opal ring, earrings or necklace.

The jewelry ranges in price from a few dollars to a few hundred.

``You never know what you're going to end up with until the final cut,'' said Hooper, turning one piece under a light so the fire flashes on the counter. ``Opal is thousands of microscopic colors. The trick to cutting it is stopping.''

The colors are spheres of silica and water suspended in the rock. The deposits formed when geysers erupted, leaving thin layers of opal that stacked up over time.

Occasionally, opal miners will find a layer thick enough to cut solid stones. More frequently the opals are made into doublets or triplets. Doublets are opal ground into a thin layer and glued on a basalt or obsidian back. Triplets are doublets that have been capped with a clear, protective quartz dome.

The dome protects the delicate gems. Opals have a high water content and tend to flake or crack as they dry out, unless they are sealed or treated with chemicals.

``I feel like I can cut as good an opal triplet as anyone in the world,'' Hooper said. ``It's not rocket science. Just a lot of tedious, time-consuming work.''

Claudia Couture knows that as well as anyone. She owns the Spencer Opal Mine, the oldest and largest mine in the area.

Couture's parents bought their 40-acre claim in 1964 and the family moved to Spencer in 1968 when she was 15. At first, they opened the mine to tourists and rockhounds who paid a set fee for a day of digging.

Now that Couture is in charge, opal-hunting tourists can still pay $30 a day, per person, on summer holiday weekends. But the mine primarily supplies her retail business.

``People have so many other hobbies than they did in the '70s,'' she said. ``Now most want to buy the jewelry already made.''

Though there are four opal operations in Spencer, the town is not competitive, she said.

``Everybody has a slightly different style or look when they cut and set the opals. And people who are really serious about buying opal will go to all four shops in town and pick the style that appeals to them,'' Couture said.

And the vagaries of the economy seem unfelt in Spencer.

``It's the birthstone for October, so it's always popular. And our profit seems to be relative to what we can produce,'' she said. ``For instance, last summer, when the economy was supposed to be fairly decent, we had one of our poorest years. And this summer we've had really good business even though there's been economic troubles nationally.''

When the Spencer Opal Mine closes for the winter -- usually around the end of October -- the Coutures move to Arizona, bringing with them raw opal waiting to be cut and set into jewelry.

The winter is also the season for gem shows, when the miners can sell directly to jewelers and wholesale companies.

``I've done this my whole life, and I've never had to work for anyone else,'' Couture said. ``I enjoy finding a really unique pattern and color combination when I cut the stones. Opal mining is just a good living.''

On the Net:
High Country Opal: http://www.opalstore.com
Opal Mountain Mines: http://www.idopalmine.com
Spencer Opal Mine: http://www.yellowstonemall.com/opal/

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