Mojave’s Fields of Gems : Recreation: Fanciers of the opal can try their luck at mining the semiprecious stone in Kern County.

This weekend, load the trunk with a rock hammer, chisels, a pick and shovel and all the water you can carry.

Your destination is Opal Canyon, the Mojave Desert home of two opal mines that allow visitors to hunt and keep the fabled semiprecious stones.

The Kern County mines are the only known sources of gem-fire opals in California, and one of only three recognized opal fields in the United States. Visitors to the mines pay $2 with the understanding they get to take home all the gems they can find.

Boy Scouts and other civic groups that wish to try their luck at digging for opals pay nothing at all, said Richard Barnett, owner of Barnett Opal Mine.

“A lot of people think (opals) are grapes on a vine that you can just come in and pick up, but it doesn’t work that way,” said Shirley Barnett, Richard’s wife of 42 years. “If it were that easy, we wouldn’t have opened this place up.”

Opal fanciers quickly discover that the gemstones lie in a finger-like spine of broken basalt known simply as the “dump.” The abrasive rubble is so inhospitable that even leather-skinned sidewinder rattlesnakes shy away, leaving opal seekers alone to unearth a gemstone that spits fire and flashes all the iridescence of a rainbow.

“For me it’s just as exciting to be out here on a weekend as it was 25 years ago,” said Richard Barnett, whose craggy, well-creased hands look like the basalt rocks he scours from sunup to sundown in his spare time.

Added his wife: “You never get over the thrill of finding a good stone.”

Fortunately, the good-natured Barnetts are far more accommodating than the hostile desert rocks.

They’ll tell you what to look for, where to look for it, how to look and how to care for your stone once you find it. And if you still walk away empty-handed, the Barnetts will usually give you an opal souvenir.

Conversely, if you find a large or rare opal in their mine, you don’t have to feel as if you’ve just picked their pockets.

“I don’t care what they take home as long as we get to look at it,” Richard said. “I’m tickled to death for ‘em.”

Shirley, who keeps some opals in a pill bottle she calls her “tranquilizer,” has an almost religious attachment to the “Queen of Gems.”

“We’re not out for the money,” she said. “We’re out for the pleasure of people enjoying themselves and being able to find something that God put on this Earth to find.”

While opals come in a kaleidoscope of colors--from milky porcelains to blacks--those usually found at the Barnett and Nowak mines are either a transparent red-orange (honies) or blue and white (jellies).

But more important than the color is the sparkle, or “fire,” that each opal possesses.

Among the Barnetts’ luminous treasures is the “Mojave Flame,” an opal that glows like coal in a barbecue pit. In 1975, the Opal Miners Assn. valued the stone in excess of $50,000.

“It’ll burn your eyes,” Richard recently told a group of wide-eyed opal hunters taking a break from the constant clattering of their rock hammers to view his collection. “The blaze in it will darn near start a fire.”

Unlike many other gems, opals aren’t dependent on being cut with facets to refract light. “It’s the only stone I know of that has true color in it,” said Richard. “It doesn’t reflect from anything else.”

Opals were formed in the El Paso Mountains during the last Ice Age as hot geyser water and silica mud percolated through porous volcanic rock, Richard said.

Over thousands of years, the mud and water collected in gas pockets in the rock, then slowly leached out, leaving behind layer after layer of silicates, the minerals found in opals and common glass.

“A (gas) pocket can be any size, from a bucket to the size of a house,” Richard said, sounding more like a geologist than a paving contractor in Bakersfield, where he works during the week.

The condensation of thermal mud and silicates is not enough, however, to provide the opal’s spark. For a “dead” opal to come alive, the ground in which it grows must be “shifted, shaken and stirred up,” Richard said.

“When the layering process is disturbed, you have a completely different molecule structure within the rock,” Richard said. “This misalignment of tiny silica beads creates the fire in the stone.”

Even armed with such knowledge, neophyte opal miners may still have trouble detecting opals, which bring about $150 a carat.

Margaret Diaz, who owns the Nowak Opal Mine with her husband, Lupe Diaz, and three other couples, said she enjoys showing city miners where to look for the gems.

“You look for the ‘honey’ in the rock or anything glassy that shines,” she said. “Then hold it in the sun and see if it hits. You can see the fire jump, unless, of course, you’re wearing sunglasses.”

Lupe plays a game of hide-and-seek with visitors as a way to improve their opal-hunting techniques. He salts a bag of worthless calcite crystals with a genuine opal and then asks them to find the stone.

“When they find it,” he said, “I have ‘em put it up against the junk they’ve already collected, and they never forget what another opal looks like.”

Richard Barnett, who uses a bulldozer and backhoe to give visitors a crack at virgin opal, estimates that about 60% of the rocks that novices discard are gem-laden.

Added Lupe: “Anything that twinkles you just about have to crack open to keep you and the rocks honest.”

Occasionally, an eager rock hound will bring a jackhammer to the mine, jarring both the desert calm of Opal Canyon and the nerves of those digging with picks and shovels.

“I just stand back and laugh,” Richard said. “It’s really a kick because this basalt is so porous that a jackhammer will go through it in about 30 seconds, and then you’re two hours digging your gad (chisel) out.”

Neither jackhammer nor rock hammer is of much use when the time comes to extricate the gemstone from its rocky matrix. For this delicate task, opal workers use a pair of “side dikes” or rock clippers.

“If you hit it with a hammer, you see what they were ,” Richard said.

But even a pulverized opal is worth something. Powdered opal is poured into plastics for penholders, while broken fire chips are inlaid like turquoise or coral into jewelry. Larger stones are made into rings, pendants and necklaces.

“We don’t waste anything,’ ” Shirley said.

Nor is an expensive lapidary unit required to shape and polish an opal.

“Glue your stone on a nail, set it in a table vise and then while you’re watching TV in the evening, use some 600 wet-dry sandpaper or a diamond fingernail file to half-way shape your stone,” Richard said. “Then take a piece of leather and some pre-polish to work up the shine. It takes a little while, but you can do it.”

Richard said he frequently receives calls from people complaining that their opal has lost its “fire.” What they don’t realize, he said, is that opals, which have a 3 1/2% water content, are thirsty stones.

“I tell ‘em to put the jewelry in a pan, bring the pan to a boil and let it cool down,” Richard said. “Then look at it in a couple of days, and sure enough the fire comes back.”

In most cases, oil or cologne has seeped into the stone and clouded it.

“You can’t change the fire in an opal,” Richard said. “You never lose it. Anybody who says they lose the fire is crazy.”

For a long time, people thought you were crazy just to own an opal. The wellspring of fire deep within the opal was seen as the fuel of mischief and misfortune.

History, at times, seems to reinforce this notion of the opal as a bad-luck stone.

For example, the Roman naturalist Pliny recorded that Marc Antony banished the senator Nonius when he refused to sell him his filbert-sized opal as a gift for Cleopatra.

In “Lapidarium,” written in 1075 by Marbodus, Bishop of Rennes, the prelate declared that the opal had the magical power to render its wearer invisible and that knowledge of this power was a closely kept secret among people who were dishonest and wicked.

In the article “Stone of Thieves and Queens” published in the 1977 edition of the International Opal Journal, the author writes that while some folks considered the stone a guardian against illness, others believed it directly responsible for the Black Death in 14th-Century Europe.

Witnesses, the author writes, often claimed they had seen a patient’s opal ring or pendant glow brilliantly just before death, and then subside.

The author concludes: “They assumed that the opal must be responsible in some way, when actually it was the rising fever and then the chill of death which produced the unique sympathetic reaction in the temperature-sensitive stone.”

The mysterious opal also played a central role in Sir Walter Scott’s novel, “Anne of Geierstein,” published in 1829. At the christening of her baby daughter, Hermione was confronted by the suspicions of an ill-favored dowager who accused her of being a demon. To allay such suspicions, Hermione’s husband placed several drops of holy water on his wife’s forehead. An opal, inadvertently moistened, sent forth a single flash before fading. Hermione collapsed and died a few hours later.

Today, Richard dismisses the opal’s controversial history as so much superstition.

“Now I think the only thing unlucky about an opal is that everybody doesn’t have one,” he said.

Richard holds this view despite the fact that the man who made the mounting for his “Mojave Flame” ring was killed in a jewelry store robbery just hours after he delivered the stone to him.

Occasionally, opal fever surfaces at the Barnett and Nowak mines.

“Some fellows a while back found a museum piece, a real trophy,” Richard said. “Then they chopped it all to pieces with their mattocks because each one was afraid the other guy was going to get more than he was.”

Richard said he booted the men off his 80-acre claim because he was so disgusted by their greed.

To get to Opal Canyon, take Highway 14 north past Edwards Air Force Base to the desert town of Mojave. Stop to refuel, then continue northeast on 14, through Red Rock Canyon.

As the bright, crimson formations of the canyon taper off into low, sandy hills dotted with desert bushes and Joshua trees, you’ll come to a black-and-white sign listing the elevation as 3,000 feet.

From there, drive another mile up the road to a sign that points east toward Opal Canyon. Turn here onto a dirt road and brace yourself for a bumpy drive of four meandering miles over a dry wash.

This last leg of the journey will take you past a series of signposts marked “Opals” that leads to both the Barnett and Nowak mines.

There’s no charge for overnight camping at either site unless you wish to stay in one of the trailers that go for $5 a night.

Each camper must supply food, water and firewood. All cans, bottles and other non-combustible trash must be carried out upon departure.

* The opal mines are located in Kern County in the Mojave Desert about 125 miles north of Los Angeles. The Barnett Opal Mine is open weekends only, (805) 399-7013. The Nowak Opal Mine is open daily, (213) 899-5744. Admission: $2 per visitor age 15 and up.

Prospecting Clubs Listed

In warm weather, the lure of buried treasure heats up for all kinds of prospectors.

For more information about treasure hunting in Southern California, write one of the prospecting clubs in your area:

* Antelope Valley Treasure Hunters Society, 42436 N. 22nd St. West, Lancaster, Calif. 93534.

* Chino Valley Prospectors, Box 2174, Fontana, Calif. 92335.

* Coin Shooters Clique of San Diego, P.O. Box 203412, San Diego, Calif 92120.

* Prospectors Club of Southern California, 4638 E. 53rd St., Maywood, Calif. 90270.

* Ramona Adventure and Treasure Seekers, P.O. Box 597, Hemet, Calif. 92343.

* Riverside Treasure Hunters Club, c/o 16454 Washington Drive, Fontana, Calif. 92335.

* The Southwestern Prospectors and Miners Assn., 9248 Stoyer Drive, Santee, Calif. 92071.

* The Valley Prospectors, P.O. Box 2923, San Bernardino, Calif. 92406.

* West Coast Prospectors and Treasure Hunters Assn., P.O. Box 2706, Orange, Calif. 92668.

* West End Prospectors Club, Ray Teagarden, 9430 Mission Blvd., Riverside, Calif. 92509.