Try <i> Noodling</i> for Your Opals in Coober Pedy

At first glance, you wonder why anyone other than kangaroos would live in this isolated outback town. The answer: opals. Coober Pedy is one of the world’s opal capitals.

Australia produces about 95% of the world’s supply of the fiery gemstone, and much of it comes from Coober Pedy.

On the town’s outskirts, the parched terrain of opal fields is pockmarked by probably 100,000 mine shafts sunk into sand and rock, and dotted by piles of rubble that have sprouted around the mines. An ounce of rock--the right rock--taken from one of these mines can net $18,000 to $20,000.

That’s reason enough for the town’s 4,000 citizens to brave desolation and live with temperatures that soar above 100 degrees for much of the year.

The name Coober Pedy comes from kupa piti, aboriginal for “white man in a hole.” It’s appropriate, because most citizens work underground and about a third live underground in dwellings carved out of the hills.

Dusty and unpaved, the main street looks like the set for a Hollywood Western, but it’s lined with opal outlets. Shops are all weathered wood, but inside, shoppers will find polished glass and gleaming gems.

The 18 opal shops offer all grades of stone and provide certificates stating stone type and weight. Prices are exceptionally good because the competition is keen.

The best strategy is to meander from the Desert Cave Underground Display to the Opal Factory to Radeka’s Underground Display to the Discount Opal House to Peter’s Opal Boutique--as many shops as possible to get the best deal on the prettiest stone you can find.

Coober Pedy opal is light blue-green with fiery streaks of orange and yellow. Loose or set, stones are sold by karat (at 152 karats per ounce), and value is determined by color and fire.

Rare and expensive is the solid or cabochon opal that is thick enough to show the depth of color and intensity of fire; it averages about $120 to $150 per karat.

Exceptional stones cost whatever the market will bear. Local vendors claim these are the world’s best prices. Shopkeepers in Adelaide and other Australian cities who dispute this would be hard put to display cheaper or matching tags.

Stones of lesser color and fire, or those that are too thin to be cut as solid opals, are prepared as “doublets,” thin slices of opal glued to darker backing that enhances the stone’s color and fire.

“Triplets” are doublets capped with thin slices of clear quartz; they cost about a third the price of solid stones. “Potch” opal, almost colorless, has little value except as a souvenir.

The opal’s special properties make it challenging to cutters. It is softer than diamonds and colored gemstones and doesn’t have their crystalline structure.

To bring out the full range of fire and color, opal roughs are cut and polished into smooth, round shapes, rather than being faceted like diamonds or colored gemstones. Even a stone that is almost flat may have an extraordinary brilliance.

Avoid buying synthetic or treated stones and beware of sellers who offer doublets or triplets as solid opals. Though the problem is unlikely here, buyers elsewhere should check opals under light for ridges of dirt and/or other signs of cracking within the stone. Most shops have displays and/or pamphlets about opal’s formation and chemical composition.

Opal was highly valued by the Romans, who obtained gemstones from traders in the Middle East. They believed opals came from India (the Roman word opalus is based on an ancient Indian word, upala , meaning precious stone).

But the stones the Romans bought were probably mined in Hungary, which remained the only source of opal known to Europeans until conquering Spaniards returned from the New World with beautiful Aztec opals mined in Mexico.

Precious opals were found in Australia in 1890 at White Cliffs in New South Wales. Mining began at Opalton in Queensland in 1896, and at Lightning Ridge (famous for black opals) in New South Wales in 1905.

In 1914, opal was discovered at Coober Pedy by a 14-year-old boy who was with his father’s gold prospecting party. By 1916, mining was well established. Coober Pedy became the world’s leading opal producer, a position it maintained until it was outstripped recently by Mintabe, a remote mining settlement about 220 miles to the northwest.

But Coober Pedy is still the best bet for tourists. Its citizens are a hardy, international bunch representing more than 40 nationalities, most of whom derive an income from either opal mining or tourism.

It’s best to visit from June through September, when milder temperatures in the 80s prevail. People come to see how an outback town functions, to overnight in underground hotels, to shop for opal bargains. Some try their hand for a day or two at ferreting out an opal or two from piles of discarded dirt and rocks that have accumulated around the mine shafts.

Sifting through already extracted rock and dirt is called noodling or fossicking and is a popular, sometimes productive pastime. All that’s needed is a spade, pail, good vision, sun screen and a lot of luck. You get to keep what you find, and that attracts visitors as well as residents who noodle from dawn to dusk.

The chances of finding very valuable stones are slim, but there are tales of tourists who found opals that later turned out to be worth thousands of dollars.

Coober Pedy is about 450 miles northwest of Adelaide. It’s 10 hours by bus. Opal Air and Kendall Air fly you here in two hours.

For more information on transportation, lodgings and tours, contact Tourism South Australia, 2121 Avenue of the Stars, Suite 1210, Los Angeles 90067, (213) 552-2821.